J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 1

Journal of the

Entomological Society of British Columbia

Volume 101 Issued December 2004 ISSN #0071-0733

Directors of the Entomological Society of British Columbia, 2004-2005 ....0......cccceccceecceceseceseeeseeeeeeeeseecsseeseeeeeeeesseeesseens 2

Gary J.R. Judd and Mark G.T. Gardiner. Simultaneous disruption of pheromone communication and mating in Cydia

pomonella, Choristoneura rosaceana and Pandemis limitata Lepidoptera:Tortricidae) using Isomate-CM/LR

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Heather L. McBrien and Gary J.R. Judd. Emergence of overwintered larvae of eye-spotted bud moth, Spi/onota ocellana

(Lepidoptera: Tortricidae) in relation to temperature and apple tree phenology at Summerland, British Columbia.....

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Gary J.R. Judd, Mark G.T. Gardiner and Howard M.A. Thistlewood. Seasonal variation in recapture of mass-reared

sterile codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae): implications for control by sterile insect

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A.L. Knight and D.M. Light. Use of Ethyl and Propy] (£,Z)-2,4-decadienoates in Codling Moth Management: Improved

Monitoring AnBartlett Pear with Hagin DOSE EAMES. scgcxesensestezieettig decnccusstroacsnncetenthcar aatccehtetees Geeeetgranaueneedceannes 45-52

A.L. Knight and D.M. Light. Use of Ethyl (£,Z)-2,4-decadienoate in Codling Moth Management: Stimulation of Ovi-

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A.L. Knight and D.M. Light. Use of Ethyl (£,Z)-2,4-decadienoate in Codling Moth Management: Kairomone Species

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A.L. Knight. Managing Codling Moth (Lepidoptera: Tortricidae) with an Internal Grid of Either Aerosol Puffers or

Dispenser Clusters Plus Border Applications of Individual Dispensers .....................:ccseeeeeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeaes 69-78

A.L. Knight and T.E. Larsen. Improved Deposition and Performance of a Microencapsulated Sex Pheromone Formula-

tion for Codling Moth (Lepidoptera: Tortricidae) with a Low Volume Application ...........0.ccccecceeeeeeeteeeteeeenees 79-86

J.E. Cossentine and L.B.M. Jensen. Persistence of a commercial codling moth granulovirus product on apple fruit and

128) f°. ere nee SESE NAT TS te mnt ene tr Oey Mem Ner ri e eanemies tire en eT Ten Tre Trew SbPael Ser bromine ever Weer weee rit ae Py 11 tacts mee tn ior earl 87-92

R.F. Smith, J.E. Cossentine, S.M. Rigby and C.S. Sheffield. Species of ground beetle (Coleoptera: Carabidae) in organic

BP Ple OLCHALAS OFS MIEISIy CO el goes sey cca anyon coon tact a veremers tesa cones vaciysassesssapeeeeiaeleisscevier eins elmer en tiene aes 93-100

David R. Horton. Phenology of emergence from artificial overwintering shelters by some predatory arthropods common

liapeat orchards Of Une P acitie IN OLE CSU oi ccc tac ts sonnets csstcsce-crasieaedeess ohceueeeanrniaouensan Aoasazes tenaereases tea emies Meee 101-108

Kevin J. Dodds and Darrell W. Ross. Douglas-fir beetle lipid levels in relation to tree physical characteristics ..........

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John H. Borden, Deepa S. Pureswaran and Lisa M. Poirier. Evaluation of two repellent semiochemicals for disruption of

attack by the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae) ................ 117-124

G.G.E. Scudder. Heteroptera (Hemiptera: Prosorrhyncha) New to Canada. Part 2 ........0..cccccccccccsseeseeeeeesseeteeeeeens 125-130

John P. Simaika and Robert A. Cannings. Lestes disjunctus Selys and L. forcipatus Rambur (Odonata: Lestidae): Some

SSO LUUCTCOTAS EQ teal Cle HCl TA ENB sak ken cng caesar cada anes ocose- a suo ones tour dune eas 131-140

SCIENTIFIC NOTES

R.S. Vernon. A ground-based pheromone trap for monitoring Agriotes lineatus and A. obscurus (Coleoptera: Elateridae)

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Sarah L. Bates and John H. Borden. Parasitoids of Leptoglossus occidentalis Heidemann (Heteroptera: Coreidae) in British

CORI D I etiegeene sae te es mes tect ar ear Tame ae Ea a pt epee oo eae soci used peared Sas anata sae 143-144

Darrell W. Ross, Gary E. Daterman and A. Steven Munson. Evaluation of the antiaggregation pheromone, 3-

methylcyclohex-2-en-1-one (MCH), to protect live spruce from spruce beetle (Coleoptera: Scolytidae) infestation in

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R.D. Kenner and K.M. Needham. New waterboatmen records for Western Canada (Hemiptera: Corixidae)...... 147-148

Christopher J. Borkent and Robert A. Cannings. Polistes dominulus (Christ) (Hymenoptera: Vespidae: Polistinae) in

British Columbia: first collection records of an invasive European paper wasp in Canada...............c:eeeees 149-150

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J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

DIRECTORS OF THE ENTOMOLOGICAL SOCIETY

OF BRITISH COLUMBIA FOR 2004-5

President:

Dave Raworth

AAFC-PARC Agassiz

President-Elect:

Karen Needham

Spencer Entomological Museum

Past-President:

Bob Vernon

AAFC-PARC Agassiz

Secretary/Treasurer:

Robb Bennett

BC Ministry of Forests, 7380 Puckle Rd. Saanichton BC V8M 1W4

Directors, first term:

Jen Perry, Hugh Philip, Niki Hobischak

Director, second term:

Vince Nealis

Regional Director of National Society:

Allan Carroll

Canadian Forest Service, Victoria

Editorial Committee, Journal:

Ward Strong (Editor), Dave Raworth,

Peter Belton, Ken Naumann, Lorraine MacLauchlan,

Editor of Web Site:

Bill Riel

Canadian Forest Service, Victoria

Co-Editors, Boreus:

Jennifer Heron and Suzie Lavallee

Honourary Auditor:

Bob Vernon

AAFC-PARC Agassiz

Web Page: http://esbc.harbour.com/

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Simultaneous disruption of pheromone communication

and mating in Cydia pomonella, Choristoneura rosaceana

and Pandemis limitata Lepidoptera: Tortricidae) using

Isomate-CM/LR in apple orchards

GARY J.R. JUDD' and MARK G.T. GARDINER’

ABSTRACT

Simultaneous disruption of pheromone communication and mating of codling moth,

Cydia pomonella (L), and four leafroller (Lepidoptera:Tortricidae) species, Choristo-

neura rosaceana (Harris), Pandemis limitata (Robinson), Archips rosanus (L.) and Ar-

chips argyrospilus (Walker ) using an incomplete mixture of their individual pheromone

components was studied in organic apple orchards, in Cawston, BC, 1997. Multi-species

disruption with a single 500 'rope' dispenser / ha application of Isomate-CM/LR was

compared to a single 500 dispenser / ha application of Isomate-C. Season-long disrup-

tion was assessed using synthetic pheromone traps and laboratory-reared females in

mating tables. Mean seasonal recaptures of sterile male C. pomonella, using 10 mg

codlemone lures in orchards receiving releases of 1000 males / ha / week, were not sig-

nificantly different in half-orchard plots (0.5 - 1 ha) of Isomate-CM/LR or Isomate-C.

Mating of C. pomonella in Isomate-C- and Isomate-CM/LR-treated plots was negligible.

Isomate-CM/LR significantly reduced catches of C. rosaceana and P. limitata relative

to catches in Isomate-C-treated plots. Few A. rosanus and no A. argyrospilus were

caught in any orchard. Mating of C. rosaceana and P. limitata in lsomate-CM/LR-

treated plots was significantly less than in Isomate-C-treated plots. Our results indicate

Isomate-CM/LR will disrupt mating of C. pomonella equivalent to Isomate-C and may

provide sufficient disruption of leafrollers to supplement biological control in organic

orchards. Further studies are needed to show impacts of mating disruption on leafroller

populations and damage when applied to larger areas and for several seasons sequen-

tially.

Key Words: Codling moth, leafrollers, mating disruption, Isomate, organic apples

INTRODUCTION

Disruption of pheromone communica-

tion and mating of moths by releasing syn-

thetic pheromones into the atmosphere is

being employed worldwide as a highly-

specific alternative to insecticides (Jutsum

and Gordon 1989; Ridgway ef al. 1990;

Cardé and Minks 1995). While the speci-

ficity of pheromone controls is appealing

for integrated programmes, this specificity

undermines use in crops where secondary

pests may become primary pests when use

of insecticides is reduced (Croft and Hoyt

1983). Apple production in the Pacific

Northwest is a good example of where

pheromone-based mating disruption

(Howell 1992; Judd et al. 1996) as a re-

placement for broad-spectrum insecticides

to control codling moth, Cydia pomonella

(L.), has resulted in increasing damage

from several species (Brunner ef al. 1994;

Knight 1995; Gut and Brunner 1998) that

are controlled to some degree by insecti-

cides targeting codling moth (Madsen and

Proctor 1985).

One solution to this problem is to

broaden the range of action of mating-

' Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland,

B.C., Canada VOH 1Z0

4 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

disruption products by combining phero-

mone components common to more than

one species, or by mixing uncommon

pheromone components from different

species. There are few published examples

of multi-species mating-disruption

(Ridgway et al. 1990; Cardé and Minks

1995) but where this has been attempted it

usually involves pheromone components

common to closely related species (Pfeiffer

et al. 1993; Deland et al. 1994; Evenden et

al. 1999a,b). For example, four species of

leafrollers (Lepidoptera:Tortricidae) found

infesting apple orchards in BC (Madsen

and Madsen 1980), the obliquebanded lea-

froller, Choristoneura rosaceana (Harris),

threelined leafroller, Pandemis limitata

(Robinson), European leafroller, Archips

rosanus (L.) and fruit-tree leafroller, Ar-

chips argyrospilus (Walker), all use (Z)-

11-tetradecenyl acetate (Z11-14:Ac) as the

major component in their multi-component

pheromone blends (Arn ef a/. 1982). In

small-plot studies, Deland ef al. (1994)

demonstrated that pheromone communica-

tion in C. rosaceana, A. rosanus, and A.

argyrospilus could be disrupted with a

93:7 blend of Z11-14:Ac and (E£)-11-

tetradecenyl acetate (£11-14:Ac), and

Evenden et al. (1999b) showed it was pos-

sible to simultaneously disrupt mating of

C. rosaceana and P. limitata with a 98:2

blend of Z11-14:Ac and £11-14:Ac. Ef-

fectiveness of unattractive, generic phero-

mone blends as mating disruptants for

these species is probably related to the fact

that attraction to pheromone dispensers,

1.e. false-trail following (sensu Bartell

1982), may not be necessary to achieve a

high percentage of disruption (Knight ef

al.1998; Evenden ef al. 1999a,b,c; Knight

and Turner 1999).

The alternative idea of using one dis-

pensing system to release pheromone com-

ponents uncommon to all species being

targeted has been around for some time

(Deventer et al. 1992), but there are few

examples or commercial products.

Isomate-CM/LR 1s a multi-species mating-

disruption product that was registered in

1997 for commercial use in the United

States to control codling moth and leafrol-

lers. Isomate-CM/LR was not registered in

Canada at that time because efficacy data

were lacking (Heather McBrien, personal

communication) and to the best of our

knowledge there are still no published data

on its use in Canada. With a view towards

registering mating-disruption products for

simultaneous control of codling moth and

leafrollers in BC we tested the utility of

Isomate-CM/LR as a commercial mating-

disruption product (Shin-etsu. Chemical

Company, Tokyo, Japan).

The primary objective of this study was

to test the hypothesis that codling moth

pheromone could be mixed in the same

reservoir and released with pheromone

components of leafrollers without compro-

mising disruption of this ‘key’ pest of ap-

ples which can be controlled with regis-

tered single-species disruption products

like Isomate-C (Judd et al. 1996,1997).

Secondly, we wanted a season-long assess-

ment of communication and mating disrup-

tion of leafrollers with Isomate-CM/LR in

commercial orchards, because previous

work was conducted for short test periods,

in small plots, with noncommercial dis-

pensers (Deland ef al. 1994; Evenden et al.

1999a,b,c). Our third objective was to

begin gathering efficacy data on Isomate-

CM/LR for Canadian registration agencies

which was lacking in 1997.

MATERIALS AND METHODS

Test Orchards. Experiments were con-

ducted in five, commercial organic apple

orchards located in the Similkameen Val-

ley, Cawston, BC (Judd et al. 1997). Or-

chards ranged in size from | - 2 ha and

were composed of mixed apple varieties

planted at densities of 600 - 900 trees / ha

with tree x row spacings of 2.4 - 4.6 x 4.6 -

5.5 m, respectively. Trees ranged in height

from 2.5 - 3.5 m and were pruned using a

pyramid shape training system. Wild

populations of codling moth were very low

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

in these orchards due to successful use of

mating disruption since 1990 (Judd ef al.

1997) and benefits derived from release of

sterile moths by the Okanagan-Kootenay

Sterile Insect Release (SIR) programme

(Dyck and Gardiner 1992). During the

current study, SIR programme staff were

releasing 1000 mixed sex (1:1 male:female

ratio) sterile codling moths in each ha of

every orchard two times each week. These

standardized releases ensured there were

approximately equal numbers of codling

moths present in all orchards where we

could assess disruption. No insecticides

were applied to these orchards during this

study.

Pheromone Disruption Treatments.

Each orchard was divided into approxi-

mately equal halves (0.5 - 1 ha). One half

was treated with Isomate-C and the other

with Isomate-CM/LR. Both of these prod-

ucts are ‘rope-type’ twist-tie dispensers

marketed by Pacific Buiocontrol Corp.,

Vancouver, WA. Isomate-C 1s a translu-

cent polyethylene dispenser containing a

155 mg blend of 58.8% (E,E)-8,10-

dodecadien-l-ol (codlemone), 29.5% do-

decanol, 5.3% tetradecanol and 6.4 % inert

ingredients. Isomate-CM/LR is a brownish

red polyethylene dispenser containing a

285 mg blend of 36.9% codlemone, 1.8%

isomers of codlemone, 6.0% dodecanol,

1.2% tetradecanol, 43.5% Z11-14:Ac,

2.4% E11-14:Ac, and 8.2% inert ingredi-

ents, with similar design and release-rate

characteristics as Isomate-C’ which has

superceded Isomate-C as a commercial

product but which contains the same active

ingredients (Don Thomson, personal com-

munication).

All pheromone dispensers were de-

ployed at a rate of 500 / ha between 1 May

and 6 May. Dispensers were attached to

branches in the upper third of the tree can-

opy ca. 0.5 - 1.0 m below the tip of the

central leader or on the first lateral branch

down from the tip.

Disruption of Pheromone Communi-

cation. Disruption of pheromone commu-

nication in codling moth was assessed by

comparing catches of SIR-released sterile

male moths in synthetic pheromone-baited

traps in the two disruption treatments.

Two Pherocon 1-CP style closed wing

traps (Phero Tech Inc., Delta, B.C.) baited

with 10 mg of codlemone (99% isomeric

and chemical purity, Shin-etsu, Fine

Chemicals Division, Tokyo, Japan) were

deployed in each pheromone-treated plot

(two traps / half-orchard treatment). Traps

were hung ca.1.5 - 2.0 m above ground

near the centre of each treatment on 8 May

and were checked weekly until 18 Septem-

ber. Trap bottoms were replaced weekly

and lures were changed every third week.

Sterile codling moths were identified by an

internal red dye sequestered from the artifi-

cial diet used to rear them (Dyck and Gar-

diner 1992).

Trap catches in pheromone-treated or-

chards were compared with catches in ad-

jacent, paired conventional orchards also

receiving sterile moths. These insecticide-

treated, but non-pheromone-treated or-

chards, are hereafter referred to as “non-

treated”. Two wing traps baited with 1 mg

of codlemone were deployed as above in

each non-treated orchard. Weekly catches

in these orchards provide a seasonal record

of sterile moth activity in the absence of

pheromone-disruption treatments.

Disruption of pheromone communica-

tion in leafrollers was assessed by compar-

ing catches of male C. rosaceana, P. limi-

tata, A. rosanus, and A. argyrospilus in the

two pheromone-treated halves of each or-

ganic orchard. Two Pherocon 1-C style

open (5 cm spacer) wing traps (Phero Tech

Inc., Delta, B.C.) baited with 3 mg (Deland

et al. 1994) of each species’ pheromone

were deployed in the middle of each

pheromone-treatment (two traps / species /

disruption treatment x four species). One

trap for each species was hung ca.1.5 - 2.0

m above ground on different sides of the

same tree, in each of two separate trees, ca.

20 m apart in the centre row of each plot.

Positions for all traps remained fixed

throughout the season. Traps were

checked weekly from June 6 until Septem-

ber 18 when moths were removed and

counted. All pheromone lures were

6 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

changed at three-week intervals and trap

bottoms were replaced as needed.

Synthetic pheromone baits for each

leafroller species were prepared with

chemical components (Aldrich Chemical

Company Inc., Milwaukee, Wisconsin,

USA) of known purity, as confirmed by

gas-chromatographic analysis (Z11-14:Ac,

98% with 2% E11-14:Ac; Z11-14:Ald,

96%; Z11-14-:0H, 97%; Z9-14:Ac, 96%,

and 12:Ac, 97%) using published ratios

(Roelofs et al. 1976a,b; Vakenti ef al.

1988; Deland ef al. 1993).

In making pheromone lures for all five

species, a 200 pl solution of each phero-

mone blend was dissolved in dichloro-

methane and loaded into separate red rub-

ber septa (Aldrich Chemical Company

Inc., Milwaukee, Wisconsin, USA). After

loading, septa were air dried for ca. 18 h at

23 °C in a fume hood and stored at 0 °C

until pinned to the inner side of trap lids in

the field.

Disruption of Mating. Disruption of

mating was assessed using virgin female

moths in mating tables described by

McBrien and Judd (1996). Only mating of

C. pomonella, C. rosaceana, and P. limi-

tata, was assessed because these were the

only species we had in rearing. C. pomo-

nella were reared on an artificial diet

(Dyck and Gardiner 1992) at 27 °C under a

16:8 h L:D photoregime and C. rosaceana

and P. limitata were reared on a modified

pinto bean-based diet (Shorey and Hale

1965) at 24 °C and 16:8 h photoregime.

Female pupae of each species were placed

individually in 150-ml plastic cups pro-

vided with a wet cotton wick until adults

eclosed. Female moths aged 24 - 72 h

were immobilized at 0.5 °C and one fore-

wing and a tarsal tip were clipped with fine

forceps before transporting them to field

sites in refrigerated containers.

Individual females of these three spe-

cies were placed in the same tree, in the

upper third of the canopy, in each of five

trees laid out in a die pattern centred in

each pheromone-treated plot. Females

were several trees removed from their re-

spective species-specific pheromone traps.

Availability of female C. pomonella al-

lowed us to deploy mating tables in non-

treated orchards for comparison, but short-

ages of leafrollers prevented this deploy-

ment. All female moths were placed in the

field in the afternoon and removed the fol-

lowing morning to minimize predation and

escape. Females recovered from the field

were returned to the laboratory and each

bursa copulatrix was dissected and exam-

ined for the presence of a spermatophore

which indicates they had mated. Females

were omitted from the data if they were

dead when recovered.

Female C. pomonella were placed in

the field on two nights, every second week

from 19 May until 6 September. Female

leafrollers were placed in the field on 2 to

4 nights, every week for three consecutive

weeks starting 3 July and 12 August which

corresponded to peak flight periods of first

and second generation, respectively.

Harvest Fruit Damage. Although our

experiments were not designed to evaluate

crop protection specifically, a sample of

2500 fruit was taken from each phero-

mone-treated plot in each of the five or-

ganic orchards in order to establish back-

ground levels of leafroller damage for fu-

ture reference. Samples were taken during

normal harvest dates as fruit maturity and

growers dictated. All fruit were examined

for damage from codling moth, including

stings and deep entries, and early and late

season leafroller feeding. Each _half-

orchard treatment was sampled by walking

a “W” pattern from corner to corner and

edge to edge and systematically choosing

25 trees, 5 edge and 20 interior trees. One

hundred fruit were removed from each

sample tree by picking 50 low and 50 high

fruit from south-side branches.

Statistical Analyses. | For each spe-

cies, moth captures from both traps in each

pheromone treatment in the same orchard

were pooled and transformed (logy [x +1])

to normalize the data. Mean seasonal cu-

mulative moth catches in the two phero-

mone treatments were compared using an

analysis of variance (ANOVA) appropriate

for a randomized block design (Zar 1984),

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

where orchards are blocks (n = 5) and there

are 2 pheromone treatments assigned ran-

domly to either half orchard. Statistical

comparisons were not made between cod-

ling moth catches in pheromone-treated

and non-treated orchards because the latter

orchards were treated with insecticides that

could confound any comparison. In addi-

tion, different strength lures were used to

monitor codling moth in pheromone-

treated and non-treated orchards. How-

ever, catches of sterile codling moths from

non-treated orchards are presented for

comparisons of their relative seasonal ac-

tivity. Low recovery of females in mating

tables meant mean percentage mating per

orchard could not be estimated reliably,

therefore recovered females were pooled

across orchards by treatment and y° tests

were used to compare the frequency of

mating in the two pheromone treatments.

A randomized block ANOVA was used to

compare mean damage estimates from the

two treatments after an arcsine Vp transfor-

mation of the data.

RESULTS AND DISCUSSION

Disruption of Pheromone Communi-

cation in C. pomonella. In non-treated

orchards the mean (+ SE) seasonal catch of

sterile codling moths / trap (1051.7 +

307.2) was several times greater than

catches in either pheromone-treatment

(Table 1). Comparing catches of C. pomo-

nella in this way likely underestimates the

level of disruption achieved by pheromone

treatments, because traps were baited with

different strength lures and _ insecticides

may have reduced catches of sterile moths

in non-treated orchards. While the SIR

programme dictated use of 1 mg lures in

conventional orchards, we chose to use 10

mg lures in pheromone-treated plots be-

cause they ensured sufficient moth cap-

tures to detect differences in pheromone

treatments. Disorientation of C. pomonella

would likely appear greater had we used 1

mg lures in pheromone-treated orchards,

because they catch very few moths in this

situation relative to 10 mg lures (Judd ef

al. 1996). Correcting for this difference in

relative attraction we calculate from

catches in Table 1, that Isomate-C caused

91% and Isomate-CM/LR caused 90%

disorientation relative to the 1051 moths

caught / trap in non-treated orchards.

There was no significant difference (P

> 0.05) in the mean seasonal number of

sterile moths caught / trap in plots treated

with Isomate-C (274.5 + 44.4) or Isomate-

CM/LR (311.9 + 126.2). This result indi-

cates that both pheromone treatments dis-

rupted orientation of codling moth to a

similar extent and therefore, the release of

leafroller pheromone components from

Isomate-CM/LR had no detrimental affect

on disruption of codling moth pheromone

communication (Table 1).

Mean weekly catches of sterile C.

pomonella pooled across pheromone-

treated orchards (Fig. 1A) reveals few

weekly differences between rates of recap-

ture in plots treated with Isomate-C or

Isomate-CM/LR, suggesting both dispens-

ers were equally disruptive under varied

weekly weather conditions. Weekly

catches of sterile moths under both phero-

mone treatments was low early in the sea-

son and began to increase near 3 July (Fig.

1A). This increase is more likely caused

by a general increase in the activity of ster-

ile moths, or response to traps as the sea-

son progressed, than by decreasing effects

of disruption treatments. This conclusion

is based on the fact that catches of sterile

males in non-treated orchards also doubled

in weeks 9 - 16 compared with weeks | - 8

(Fig. 1A).

Disruption of Pheromone Communi-

cation in Leafrollers. Mean seasonal

catches of C. rosaceana and P. limitata

were both significantly (P < 0.05) lower in

the Isomate-CM/LR treatment than in the

Isomate-C treatment (Table 1). Almost no

Archips spp. were caught in any orchards,

supporting the view that these species are

generally found further north and more

8 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

Seasonal cumulative catches of male moths in synthetic pheromone-baited traps and mating of

sentinel females in mating tables for each of four species in each half of five organic apple

orchards treated with different commercial pheromone dispensers, Cawston, BC, 1997.

Commercial pheromone disruption Mean (+ SE) number

treatment (500 dispensers / ha)

Moth species’

Isomate-C

Isomate-CM/LR

C. pomonella

Isomate-C

Isomate-CM/LR

C. rosaceana

Isomate-C

Isomate-CM/LR

P. limitata

Isomate-C

Isomate-CM/LR

A. rosanus

Isomate-C

Isomate-CM/LR

A. argyrospilus

% of females

of moths / trap” mating”

275.5+ 44.4a 0.0a

311.9+ 126.2a 0.9a

752.7 + 356.8a 25.9a

124.2 + 187.6b 7.8b

542.7 + 241.5a 32.6a

84.7 + 103.7b 5.6b

2.0+ 0.8 nt 0.0 nt

00 00 0.0

00+ 0.0nt 0.0 nt

002 “0:0 0.0

' All C. pomonella caught were sterile moths released (1000 males / ha / orchard / week) by the

Okanagan-Kootenay Sterile Insect Release Programme.

> Means of seasonal cumulative catches in two traps in each of five orchards. Paired means

within a species followed by different letters are significantly different (P < 0.05) by Random-

ized Block ANOVA. nt = no test.

* Paired percentages within a species followed by different letters are significantly (P < 0.05)

different by x’ tests on observed frequencies of mating.

frequently in the Okanagan than in the

Similkameen Valley (Madsen and Madsen

1980).

Weekly catches of C. rosaceana are

shown in Fig. 1B. Catch curves in both

treatments reflect a large first-generation

and small second-generation flight. This

pattern is typically seen in insecticide-

treated orchards and is thought to occur

because insecticides applied during first

generation reduce second-generation popu-

lations (Madsen and Madsen 1980). This

cannot explain our results because organic

orchards were not treated with insecticides.

A small second-generation flight may arise

because first-brood larvae often enter dia-

pause early in this region. Therefore, con-

trol of this first generation is important

because it prevents an escape of insects

that give rise to an overwintering popula-

tion with potential to undermine long-term

control.

Weekly catches of C. rosaceana were

reduced 70.9 - 100% in the Isomate—CM/

LR treatment relative to the Isomate-C

treatment (Fig. 1B), and reductions aver-

aged 90.3% for the season across all or-

chards (Table 1). Deland et al. (1994)

reported a similar 89 - 91% average disori-

entation of C. rosaceana to synthetic

pheromone traps in 0.1 ha plots treated

with 1000 - 2000 Hamaki-con (Shin-etsu

Chemical Company Ltd., Tokyo, Japan)

dispensers per ha, releasing a 93:7 blend of

Z11-14:Ac and £11-14:Ac at ca. 20 - 40

mg / ha / h (Deland 1992). Given that a

single Isomate-CM/LR dispenser releases

ca. 1 mg Z11-14:Ac / day in the Okanagan

Valley (GJRJ, unpublished data), 500

Isomate-CM/LR dispensers would release

ca. 21 mg / ha/h. Therefore, using more

than 500 Isomate-CM/LR dispensers per

ha to disrupt C. rosaceana would seem

unwarranted.

Weekly catches of P. limitata are

shown in Fig. 1C. Unlike catches of C.

rosaceana, which showed two distinct

peaks in the Isomate-C treatment (Fig. 1B),

catches of P. limitata remained high all

season in the Isomate-C treatment (Fig.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

a Isomate-CM/LR

Cydia pomonella

Pandemis limitata

Mean Number of Moths Caught / Trap / Week

[etl Isomate-C

ZA Non-treated

ee eee

Date

Figure 1. Mean weekly catches of mass-reared, sterile male Cydia pomonella released by the

Okanagan-Kootenay SIR Programme (A), wild male Choristoneura rosaceana (B) and wild

male Pandemis limitata (C) in their respective species-specific synthetic pheromone-baited

traps hung in non-treated conventional apple orchards (C. pomonella) and in Isomate-C- and

Isomate-CM/LR-treated halves of organic apple orchards (all species) in Cawston, BC, 1997.

1C). This is quite different from the two

distinct peaks Madsen and Madsen (1980)

observed in insecticide-treated conven-

tional orchards. Catches of P. limitata in

the Isomate-CM/LR treatment showed

early and late season peaks, but moths

were always being caught in low numbers.

A second peak in the Isomate-CM/LR

treatment may indicate leafroller phero-

mone was running out late in the season as

found by Knight et a/. (2001). Given the

date dispensers were deployed and a | mg /

day release rate, dispensers were expected

to run out of Z11-14:Ac between 24 - 30

August, exactly when the second peak of

catches occurred (Fig. 1C). To make it a

reliable product more data are needed on

the release of various pheromone compo-

nents from Isomate-CM/LR dispensers in

relation to temperature.

Weekly catches of P. limitata were

reduced 67 - 100% by treatment with

Isomate-CM/LR (Fig. 1C) and reductions

averaged 88.9% for the season across all

orchards (Table 1), relative to the Isomate-

C treatment.

Disruption of Mating in C. pomo-

nella. Mating of C. pomonella in non-

10 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

treated orchards receiving sterile moths

averaged 48.7% during late May and June

and 59% in July and August. In spite of

very large numbers of sterile males being

released in this study (1000 / ha / week),

almost no sentinel female C. pomonella

mated in either pheromone treatment, and

there was no significant difference (y° =

0.34, df= 1, P > 0.05) in the frequency of

mating in the Isomate-C (0 / 223) and

Isomate-CM/LR treatments (2 / 212).

Mating frequency of C. pomonella in our

Isomate-C treatment was quite low when

compared with the frequencies of mating

among feral codling moths reported by

Knight (1996) using passive pane traps, or

by Howell (1992) using black light traps,

both in Isomate-C-treated orchards. While

there may be discrepancy between differ-

ent assessment methods, our evaluation of

mating is suitable in this context because

the relative difference in mating between

the two pheromone treatments is of interest

here. Given that Isomate-Cis known to

control populations of C. pomonella (Judd

et al. 1996) and there appears to be little

difference in levels of trap disorientation

and mating disruption using Isomate-CM/

LR, we expect the level of control with

these two products to be simular.

Disruption of Mating in Leafrollers.

On average, 25.9% (14 / 54) of female C.

rosaceana and 32.6% (34 / 104) of female

P. limitata mated when placed in the

Isomate-C treatment having no leafroller

pheromone, while only 7.8% (5 / 64) and

5.6% (6 / 107) of each species, respec-

tively, mated in the Isomate-CM/LR treat-

ment. Isomate-CM/LR significantly (y° =

5.84, df = 1, P < 0.05) reduced mating of

C. rosaceana by 70% and P. limitata by

83% (y° = 23.4, df = 1, P< 0.001), relative

to the Isomate-C treatment. Our seasonal

level of mating disruption in C. rosaceana

was somewhat lower than the 86% ob-

served by Evenden et al. (1999b) using a

similar blend (100:2 ratio of Z11-14:Ac

and £11-14:Ac) and the same dispenser

density (500 / ha) in 0.1 ha plots. Lower

levels of disruption in our study may be

due to higher population densities, or

movement of Z11-14:Ac into the Isomate-

C treatment used for comparison. Simulta-

neous release of codlemone from Isomate-

CM/LR dispensers cannot explain any dif-

ferences between these studies because C.

rosaceana is not known to detect this

chemical (GJRJ, unpublished electroanten-

nograms).

Mating of C. rosaceana was similar in

first (7.4%) and second generation (8.1%)

and although catches of P. limitata in-

creased during second generation (Fig.

1C), there was no increase in the frequency

of their mating between first (7.5%) and

second (2.4%) generation in Isomate-CM/

LR-treated plots. Therefore, the amount of

pheromone being released late in the sea-

son appears to have been adequate to con-

trol mating in leafrollers even if catches

appeared to increase (Fig. 1C). Our 83%

seasonal average mating disruption for P.

limitata was similar to the 85% observed

by Evenden ef al. (1999b) when 1000 dis-

pensers / ha were employed. Like C.

rosaceana above, there may be little value

in using more than 500 Isomate-CM/LR

dispensers per ha to disrupt mating in P.

limitata.

Fruit Damage. As expected given low

levels of wild codling moths, release of

sterile males, and treatment with phero-

mone, there was no detectable codling

moth damage in any orchard. _Leafroller

damage was very high in these organic

orchards and there was no significant (P >

0.05) difference in the mean percentage of

damage in plots receiving Isomate-C (10.9

+ 5.4%) or Isomate-CM/LR (8.7 + 4.7%).

These damage levels suggest densities of

leafrollers were very high and crop protec-

tion can fail under high population densi-

ties even if measures of disruption are

large (Judd et al. 1996, 1997). While we

do not consider our experiment to be a fair

evaluation of leafroller control by mating

disruption, these data should provide a

useful baseline for longer-term mating-

disruption trials.

Our studies have demonstrated it 1s

possible to simultaneously disrupt phero-

mone communication and mating in sym-

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

patric tortricid moths by releasing an in-

complete mixture of their individual phero-

mone components. Levels of disorienta-

tion and reductions in mating of all species

with Isomate-CM/LR were comparable to

those seen in studies examining each spe-

cies individually (Deland et al. 1994;

Evenden et al. 1999a,b,c). Our data sug-

gest control of codling moth with Isomate-

CM/LR should be comparable to control

with registered products like Isomate-C”

and Isomate-C (Judd et al. 1996).

Isomate-CM/LR also has potential for sup-

plementary control of leafrollers. These

conclusions are supported by several stud-

les using Isomate-CM/LR in Washington

State (Knight et a/. 1997; Knight 1998;

Knight et al. 2001). These non-refereed

reports suggest that when used on an area-

wide basis for three years (1998 - 2000),

orchards treated with Isomate-CM/LR and

supplemental insecticides had 41% less

leafroller damage, received one less spray

per season and consistently had less cod-

ling moth damage than orchards receiving

Isomate-C” and supplemental sprays.

Lacking in these studies unfortunately,

are data from Isomate-CM/LR-treated or-

chards receiving no supplemental insecti-

cides. Ours is the only evaluation of

Isomate-CM/LR where no _ insecticides

were applied and the only one reporting

actual mating data that we are aware of.

These kinds of data are useful for registra-

tion of pheromones in Canada. Efficacy

data based on fruit damage are also needed

but our study lacks this assessment because

the split-orchard design resulted in treat-

ment areas too small to prevent movement

of mated females or ballooning larvae be-

tween treatments. Therefore, it remains to

be shown whether measures of disruption

observed here will impact the population

dynamics of these species and control

damage effectively without use of insecti-

cides. In this regard, Isomate-CM/LR may

have a role to play in supplementing bio-

logical control of leafrollers in organic

apple orchards where parasitism rates as

high as 68% are common during summer

in the Similkameen Valley (Cossentine ef

al. 2004).

During the revision of this manuscript

Isomate-CM/LR was registered by the Ca-

nadian Pest Management Regulatory

Agency (Heather McBrien, personal com-

munication). Nevertheless, multiple-year

mating-disruption trials still need to be

conducted in larger orchards, or on an

area-wide basis (Knight et a/. 2001), and

under lower population pressure than seen

in this study, before any conclusions about

the efficacy of mating disruption as a crop-

protection tool for leafrollers in BC can be

made.

ACKNOWLEDGEMENTS

We thank the Similkameen-Okanagan

Organic Producers' Association (SOOPA)

and its cooperating members for allowing

us to conduct trials in their orchards. We

also thank Nicole Verpaelst for technical

field assistance. We especially thank Don

Thomson from Pacific Biocontrol Corpora-

tion for making Isomate-CM/LR available

for testing and sharing technical data on

this product. This research was partially

funded by the Washington State Tree Fruit

Research Commission, SOOPA and the

Agriculture and Agri-Food Canada Match-

ing Investment Initiative.

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J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 15

Emergence of overwintered larvae of eye-spotted bud moth,

Spilonota ocellana (Lepidoptera: Tortricidae)

in relation to temperature and apple tree phenology

at Summerland, British Columbia

HEATHER L. MCBRIEN” and GARY J.R. JUDD”

ABSTRACT

We recorded daily appearance of overwintered larvae of eye-spotted bud moth (ESBM),

Spilonota ocellana (Denis & Schiffermiiller) in spring 1992, 1994, and 1996 in an un-

sprayed apple orchard at Summerland, British Columbia, to relate larval emergence to

degree-day (DD) accumulation and apple phenology. In all years the first larva was

found between mid-March and early April, and none appeared after late April. Median

emergence of larvae occurred when McIntosh apple trees were at early, tight-cluster

stage of fruit-bud development. Larval head capsule measurements showed that ESBM

usually overwinter as fifth and sixth instars, with a small proportion (<6%) as fourth-

instar larvae. In the laboratory we monitored emergence of non-diapausing overwin-

tered larvae from apple branches incubated at 8.8, 9.4, 12.9, 15.0, 18.0, and 20.9 °C. A

least-squares linear regression described emergence over this temperature range rela-

tively accurately (r° = 0.57, P < 0.05) and a base temperature for emergence (7; = 1.0 °C

+ 0.6) was extrapolated from this regression. Regression analysis indicated median

emergence should require 154.6 + 6.7 DD above 1 °C (DDj;°c). Using daily air-

temperature maxima and minima and | March to start accumulating DD; :c, the error

between predicted and observed days to median emergence in the field was -6.7 + 3.1 d;

the regression model predicted early in every case. Using observed larval appearance on

apples (1992, 1994, & 1996) and an iterative process, we determined that a combination

of 6 °C as the 7, and 1 January as a date to start accumulating DD6-c, minimized the

coefficient of variation for the three-year mean DD¢-c accumulations (82.7 + 3.5 DD¢6«c)

required for 50% of the larvae to appear in the field. While this latter DD index de-

scribed observed emergence of larvae accurately, and its use may help improve manage-

ment of ESBM, it should be validated using independent data before growers use it rou-

tinely.

Key Words: Spilonota ocellana, Tortricidae, larval development, phenology, degree

days

INTRODUCTION

The eye-spotted bud moth (ESBM), hemisphere (Weires and Riedl 1991).

Spilonota ocellana (Denis and Schiffer-

miiller), is a pest of apple (Gilliatt 1932,

MacLellan 1978), blueberry (Gillespie

1985), cherry (Oatman et al. 1962), and

prune (Madsen and Borden 1949) through-

out fruit-growing areas in the northern

ESBM is univoltine and larvae overwinter

in hibernaculae on branches of host plants.

Larvae crawl from hibernaculae in early

spring to feed on leaves and blossoms.

Pupation occurs in a nest of dead leaves

and blossoms held together with silk.

' Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland,

British Columbia, Canada VOH 1Z0

>Current address: Pest Management Regulatory Agency, Sir Charles Tupper Building, 2720 Riverside

Dr., Ottawa, Ontario, Canada K1A 0K9

* Author to whom correspondence should be addressed

16 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Adults emerge in early summer and lay

eggs singly on leaves (Weires and Riedl

1991, McBrien and Judd 1998). Summer-

generation larvae arising from these eggs

often feed on fruit surfaces causing dam-

age and discolouration beneath leaves at-

tached to fruit with silk (Gilliatt 1932).

In North America, ESBM has a history

of sporadic outbreaks in apple orchards

(MacLellan 1978) because insecticides

applied in summer against codling moth,

Cydia pomonella (L.) often control it indi-

rectly (Madsen and Downing 1968, British

Columbia Ministry of Agriculture, Fisher-

ies and Food 2004). As non-insecticidal

methods like sterile male technique (Dyck

and Gardiner 1992) or pheromone-based

mating disruption (Judd et a/. 1996, Judd

and Gardiner 2004) have been imple-

mented to control codling moth and lea-

frollers (Tortricidae) in Bntish Columbia

(B.C.), feeding damage by ESBM has in-

creased (GJRJ unpublished data), mirror-

ing reports from The Netherlands

(Deventer et a/. 1992). Therefore, control

of ESBM in spring has become more criti-

cal. Insecticides applied in spring are often

timed to control leafrollers and green fruit

worms (Noctuidae), providing control of

ESBM only indirectly (Madsen and Down-

ing 1968, British Columbia Ministry of

Agriculture, Fisheries and Food 2004).

Therefore, strategies to control ESBM spe-

cifically need to be developed.

The ability to predict when overwin-

tered larvae of ESBM appear in spring

would be a useful tool in designing an inte-

grated management programme. The

phenology of ESBM larval emergence in

spring has been related to apple phenology

in other areas (Gilliatt 1932, Madsen and

Borden 1949, Oatman ef a/. 1962) but this

approach has not been validated in B.C.,

Canada, and may not provide consistent

prediction of emergence on different spe-

cies of host plant and on different varieties

of fruit trees across different years. A tem-

perature-based model to predict emergence

of overwintered larvae may be a more use-

ful approach as this technique has been

applied successfully against other species

of leafrollers in the Pacific Northwest

(Brunner 1991). We describe emergence

of overwintered larvae of the ESBM in

relation to degree-day (DD) accumulations

and apple tree phenology.

MATERIALS AND METHODS

Collecting and Handling Prunings.

Several hundred 30-cm branch sections

were pruned from a mixed block of

McIntosh, Delicious, and Spartan apple

trees in an experimental apple orchard at

the Pacific Agri-Food Research Centre

(PARC) in Summerland, B.C. on 2 Febru-

ary 1992. No insecticides were applied to

this orchard for at least five years preced-

ing or during this study and it was heavily

infested with ESBM larvae in 1991. Prun-

ings consisting mainly of fruit-spur wood

and excluding previous years’ growth were

transported to the laboratory, stored in

cardboard boxes filled with moist sawdust,

and held in darkness at 0.4 + 0.5 °C until

required.

Diapause Termination. Before as-

sessing temperature-dependent emergence

of overwintered larvae, it was important to

ensure they had completed diapause so that

some portion of diapause development was

not included in any estimates of post-

diapause development time. Prunings col-

lected on 2 February and 1 March 1992,

when apple buds were still dormant, were

placed in a controlled-environment cham-

ber at 19 °C under a 13:11 h L:D photo-

regime provided by Daylight fluorescent

tubes. On each collection date, seventy

30-cm-long prunings were placed in a plas-

tic basin (35 cm x 35 cm x 16 cm), cov-

ered with polyester organza and held in

place with an elastic band that prevented

larva from escaping but permitted air cir-

culation. On 1 March, an equivalent

length of pruned branch sections was re-

moved from laboratory cold storage (0.4

°C) and set up identical to other pruning

samples. Every 24 h, prunings were re-

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

moved from their basin and tapped sharply

to dislodge active larvae onto a white

cloth. The number of larvae collected

daily was recorded and sampling was ter-

minated when larvae went undetected for

seven consecutive days after they began

appearing.

Emergence at Constant Tempera-

tures. On 7 May 1992, 66 days after being

placed at 0.4 °C as part of the diapause

study, ca. five hundred 30-cm sections of

prunings were removed from cold and di-

vided evenly among eight basins described

previously. One basin of prunings was

placed in each of seven separate con-

trolled-environment chambers set at 3.8,

8.8, 9.4, 12.9, 15.0, 18.0, or 20.9 °C, re-

spectively, each with a photoregime of

13:11 h L:D. One basin of prunings was

returned to 0.4 °C. Constant-temperature

conditions were chosen to approximate the

range of air temperatures and photoregime

normally experienced by ESBM larvae

during spring in the Okanagan Valley.

When prunings were placed in controlled-

temperature chambers on 7 May 1992,

larvae in the field had completed emer-

gence.

One larva emerged on day 54 from

prunings incubated at 0.4 °C and three lar-

vae emerged on days 9, 18, and 46 from

prunings incubated at 3.8 °C. Therefore,

on | July, 55 d after incubation, prunings

were transferred from 0.4 and 3.8 °C to the

18 °C constant-temperature incubator to

determine if larvae would emerge at the

higher temperature and if their emergence

times would be shorter than those placed at

constant 18 °C from the outset.

Linear Regression-based Emergence

Model. A linear DD emergence model,

lower threshold base temperature (7;), and

the DD requirements for median (50%)

emergence of larvae were determined ana-

lytically using linear regression techniques

(Campbell et al. 1974) applied to labora-

tory-derived constant-temperature emer-

gence data. Emergence time in days for

each larva at each constant temperature

was converted to an emergence rate by

taking the reciprocal (developmental rate =

1 / days to emerge). Emergence rates for

all larvae at each temperature were re-

gressed against temperature using least-

squares linear regression analysis (Zar

1984). Extrapolating this linear regression

through the x-axis gave the theoretical

lower developmental threshold base tem-

perature (Arnold 1959). The number of

DDs needed for emergence of 50% of the

larval population was determined by taking

the reciprocal of the slope of the linear

regression line (Campbell et al. 1974).

Standard errors for estimates of 7, and DD

totals were calculated as described by

Campbell et al. (1974). Two ESBM larvae

emerged within 1 d of incubation at 20.9

°C. The emergence rates for these two

larvae were considered outliers and ex-

cluded from linear regression analysis in

order to maintain homogeneity of variance

(Zar 1984).

Phenology of Larval Emergence in

the Field. Prunings infested with overwin-

tered ESBM larvae were collected from the

experimental apple orchard in early March

1992, 1994, and 1996. Collections were

made while apple buds were dormant and

before ESBM larvae had started to crawl

from overwintering hibernaculae. As be-

fore, prunings mainly consisted of fruit-

spur wood and did not include previous

years’ growth. Wood was cut into 30-cm-

length pieces and placed in cylindrical

mesh bags (length = 60 cm, diameter = 25

cm) made from polyester organza and tied

at both ends with string. Each of eight

mesh bags was filled with 30 prunings and

suspended 1.8 m above ground from an

apple tree in the experimental orchard.

Bags were suspended from a branch on the

north side of trees to minimize exposure to

direct sunlight. Each bag was hung from a

separate tree in the lower half of the can-

opy but above the lowest scaffold branch.

No bags were hung in the border row of

trees.

Each day, each pruning was removed

from its bag and tapped sharply on a white

plastic tray to dislodge active larvae. The

inside of each bag was checked for larvae

after which prunings were returned to bags

18 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

and rehung in trees. Numbers of larvae

collected from each bag were recorded,

and the total number collected from all

bags was pooled each day. Bags were

checked until no larvae were counted for

seven consecutive days after the first larva

appeared. The phenology of a sample of

20 fruit buds on McIntosh apple trees in

the study site was recorded every two to

three days. Fruit-bud phenology is de-

scribed by British Columbia Ministry of

Agriculture, Fisheries, and Food (2004).

Instars of Overwintered Larvae.

Head capsule widths of overwintered lar-

vae were measured from prunings col-

lected on 1 March 1992 as part of the dia-

pause termination study, and from prun-

ings used to monitor larval emergence in

the field during 1994 and 1996. Each larva

that emerged from prunings was preserved

in 70% ethanol and its head capsule width

was measured to determine instar (Gilliatt

1932). Gilliatt (1932) did not provide esti-

mates of variation for the head capsule

width of each of the seven larval instars,

therefore, the midpoint between the mean

head capsule width for each successive

instar was used as the range for classifying

each instar.

Temperature Measurement and DD

Accumulation. Hourly air temperatures in

the PARC apple orchard were recorded

throughout the study using a DP-212 data-

pod (Omnidata™, Logan, UT, USA)

housed at l-m height in a Stevenson

screen. Degree-day summations were cal-

culated by fitting a sine wave (Allen 1976,

case 4) to daily air-temperature minima

and maxima using the computer pro-

gramme described by Higley ef al. (1986).

Degree-day summations were calculated in

1992, 1994 and 1996 using all possible

combinations of lower threshold base tem-

peratures consisting of 1, 2, 3, 4, 5, 6, 7 or

8 °C, and 1 January, February, or March as

dates to start summation. Accumulations

from each start date up to the Julian Day

(JD) on which 50% of the larvae appeared

in the phenology sampling performed

above were calculated. Temperatures <9

°C were chosen as possible base tempera-

tures because the majority of larvae incu-

bated at constant temperatures <8.8 °C in

the laboratory never emerged. No upper

temperature threshold was set. The coeffi-

cient of variation (CV) among these DD

calculations for individual years was calcu-

lated for each combination of base tem-

perature and starting date. The combina-

tion of base temperature and starting date

which gave the lowest CV (Arnold 1959)

was chosen to generate DD summations

that best described the observed cumula-

tive larval emergence in 1992, 1994 and

1996. Cumulative larval emergence data

(1992, 1994, and 1996) was plotted against

these DD summations and a cumulative

Weibull function was fitted to this scatter

plot (McBrien and Judd 1998).

Statistical Analyses. All statistical

analyses were performed with SigmaStat*

(Version 3.0.1, SYSTAT Software Inc.,

Richmond, California, USA) and all ex-

periment-wise error rates were set at a =

0.05.

RESULTS AND DISCUSSION

Diapause Termination. The average

number of days required for ESBM larvae

to appear from prunings incubated at 19 °C

following collection at various dates or

removal from cold storage are shown in

Table 1. Fifty percent of the 74 larvae

coming from prunings collected on 2 Feb-

ruary appeared in 9.7 d, whereas 50% of

the 66 larvae coming from prunings col-

lected on 1 March did so in 6 d. This dif-

ference represents a 38.1% decline in days

to appear following 28 d of field aging. By

comparison, 50% of the 83 larvae coming

from prunings collected on 2 February but

stored at 0.4 °C for this 28-day period, did

so in 8.6 d, representing an 11% decline in

days to appear compared with larvae on

prunings collected 2 February, but immedi-

ately incubated at 19 °C (Table 1).

Knowing when diapause terminates is

critical to construction and application of

any DD model because it establishes a

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

Time needed to emerge (days) at 19 °C for larvae of S. ocellana collected from the field or

removed from laboratory cold storage in February and March 1992.

Collection and

Median emergence time

Mean (+ SD) emergence time

incubation Laboratory Field Laboratory Field

dates stored! collected stored! collected

2 February - 9.7 - 10.8 + 2.3

1 March 8.6 6.0 9042.3 7042.3

'One half of first field collection (2 February) was placed in laboratory cold storage (0.4 °C)

and removed at time of second field collection (1 March)

biologically relevant time at which these

accumulations might start and it ensures

more accurate determination of post-

diapause development times. Whether

overwintering larvae of ESBM undergo

true obligatory diapause (Danks 1987) is

not known nor was it determined because

prunings were collected too late in winter

to investigate this aspect of larval develop-

ment. Those cues that might end diapause

in ESBM are not known, but in temperate

insects there is often a minium time re-

quirement before post-diapause develop-

ment begins (Danks 1987). Whatever cues

are necessary to break diapause in ESBM,

larvae clearly develop in February if tem-

peratures are appropriate. As diapause

progresses or terminates in many species,

observed times for the diapausing life stage

to hatch or emerge often shortens and be-

comes more synchronous (Tauber and

Tauber 1976). Thus, a decline in average

days to appear or emerge during incubation

that begins at different times in winter is

often an outward manifestation of diapause

progression (Judd ef a/. 1993, 1994). Our

observation that average time until larvae

appeared on prunings incubated at 19 °C

after storage at 0.4 °C from 2 February to 1

March, was only 11% shorter than those

incubated at 19 °C on 2 February (Table 1),

suggests most larvae were out of diapause

by 2 February. By comparison, larvae

stored in the field during this same period

appeared sooner when placed at 19 °C on 2

March (Table 1) than on 2 February, indi-

cating they had probably undergone some

post-diapause development in the field.

Therefore, most ESBM larvae probably

complete diapause by 2 February and un-

dergo post-diapause development when

temperatures are above 0.4 °C as they were

in the field at this time of year. Collec-

tively, these data indicate larvae on prun-

ings removed from cold storage after 1

March were suitable for studies on post-

diapause development and 1 February

might be a suitable time to start DD accu-

mulations in the field.

Emergence at Constant Tempera-

tures. The relative frequency of days to

appear for larvae incubated at constant

temperatures between 8.8 and 20.9 °C are

shown in Fig. 1. The median and mean

days to appear are similar at each tempera-

ture indicating that each overall distribu-

tion is approximately normal (Zar 1984).

After 54 d of incubation at 0.4 and 3.8 °C,

only | and 3 larvae had appeared on these

prunings, respectively (Fig. 1). On day 55

these prunings were transferred to 18 °C

and after transfer, 50% of 65 and 33 larvae,

respectively, appeared within 8.7 and 6.2

d. These respective median times were 0.2

and 2.7 d shorter than times taken for 50%

of the larvae incubated at constant 18.0 °C

to appear (Fig. 1). Obviously, there was

little or no development occurring at 0.4

°C, while a 2.7-d shorter median emer-

gence time indicates some development

probably occurred during 54 d of incuba-

tion at 3.8 °C.

Linear Regression-based Emergence

Model. Linear regression (Fig. 2) of the

relationship between emergence rates ()

and temperatures (x) between 8.8 and 20.9

°C (vy = 0.0066 x - 0.0067) provided a rea-

sonable description (7° = 0.57, P < 0.05) of

20 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

8.8 °C

0.25 aaa

0.20 Median = 21.2 d

Mean = 21.8+6.7d

0.15

0.10

0.05

0.00 ms

(6) 10 20 30 40

rad)

- 94°C

c 0.25 n= 55

rd) eae

vw 020 Median = 17.5d

(e)

Mean = 18.34+5.4d

a 0.15

@©

S 0.10

= 0.05 !

= 0.00 TL a

—

as 0 10 20 30 40

r«)

(ad

12.9°C

0.25

n= 76

0.20 Median = 13 d

0.15 Mean = 14+3.7d

0.10

0.05

0.00 i

0 10 20 30 40

15.0 °C

n= 57 0.28

Median = 10.9d 0.20

Mean =12+3.4d

0.15

0.10

0.05

ll 0.00

0 10 20 30 40

16.0°C

n= 58 0.25

Median = 8.9d

edian 0.20

Mean = 10.2+3.2d

0.15

0.10

0.05

ii = 0.00

0 10 20 30 40

20.9 °C

0.25

n= 62

Median = 7.1 d 0.20

Mean =7.4+£1.9d 0.15

Days to emerge

Figure 1. Relative frequency histograms for daily emergence of post-diapause overwintered

larvae of S. ocellana held at various constant temperatures.

the observed emergence data.

Extrapolation of this line to the x-axis

provides a theoretical estimate (1.0 + 0.6

°C) for the lower developmental threshold

(T;). The reciprocal of the slope of this

regression line indicates that half the popu-

lation of ESBM larvae should appear in

154.4 + 6.7 DD; «c.

Phenology of Larval Emergence in

the Field. Fig. 3 shows relative frequency

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

0.15

[S)

oD)

ie)

op)

H |

& 0.05 a

cD)

= | 7

0.00 ~

fe) 5

15 20 25

Incubation temperature (° C)

Figure 2. Mean (+ SD) emergence rates (solid circles ) of post-diapause overwintered larvae

of S. ocellana at temperatures between 8.8 and 20.9 °C. A least-squares regression line (solid

line) was fitted to individual larval emergence rates and extrapolated (dotted line) to the x-axis

to estimate the base temperature threshold, 7, (1.0 + 0.6 °C).

curves for daily larval emergence each

year. The dates for first emergence ranged

from JD 75 (15 March) in 1992 to JD 96 (5

April) in 1996. Fifty and 100% emergence

occurred between 0 - 14 and 25 - 35 d,

respectively, after the first larva was de-

tected each year. The first ESBM larva

was found in the field when McIntosh ap-

ple trees were at early green-tip stage of

bud development. Fifty and 95% larval

emergence consistently occurred in early,

tight-cluster and late, pink-bud stages, re-

spectively (Table 2). All larvae had

emerged shortly after bloom began. Previ-

ous observations on appearance of over-

wintered ESBM larvae in spring have

noted that larvae begin to emerge soon

after buds begin to open (Gilliatt 1932,

Madsen and Borden 1949, Oatman ef al.

1962).

Instars of Overwintered Larvae.

Among the 66 larvae which appeared on

prunings incubated in the laboratory after

field collection 1 March 1992 (Table 1), 7,

70 and 23% were fourth, fifth, and sixth

instars, respectively. Among the 178 lar-

vae that appeared on prunings during field

observation in 1994, 5, 70 and 25% were

fourth, fifth, and sixth instars, respectively.

The distribution of instars in 1994 was not

significantly different (y° = 0.614, df =2, P

= 0.736) than the distribution of larval in-

stars observed in the laboratory in 1992.

In 1996, 6, 43, and 51% of the 64 larvae

observed on prunings in the field were

fourth, fifth, and sixth instars, respectively.

While the proportion of fourth instars in

1996 was similar to that in 1992 and 1994,

the overall distribution of instars in 1996

was significantly different from 1992 (y° =

11.778, df = 2, P < 0.003) and 1994 (x? =

16.677, df = 2, P < 0.001) because of a

greater percentage of sixth instars in 1996.

In 1994, 50% of fourth, fifth, and sixth

instars appeared in the field by JD 97, 101,

and 102, respectively; in 1996 they oc-

curred on JD 106, 108, and 102, respec-

tively. When all larval instars are consid-

ered together 50% appeared by JD 100 in

1994, and JD 106 in 1996 (Table 2, Fig. 3).

ESBM has seven larval instars, and on

apple, larvae reportedly overwinter in the

fifth instar (Gilliatt 1932, LeRoux and

Reimer 1959, MacLellan 1978). However,

Gilliatt (1932) observed that some larvae

also overwinter in the fourth and sixth in-

27 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

1992

0.15

0.10

0.05

0.00

= 1994

OG 015

o))

ro)

= 0.10

ro)

Ss 0.05 -

0.00 7

1996

0.05

0.00 —

}

° |

95 100 105 110 115 120 125

Julian date

Figure 3. Percent of overwintered larvae of S. ocellana emerging daily in 1992, 1994, and

1996. Total larvae emerged in 1992, 1994, and 1996 were 105, 178, and 64, respectively.

stars. Oatman ef al. (1962) reported that

on sour cherry ESBM larvae entered hiber-

naculae in autumn as third instars and then

moulted sometime before appearing in

spring. According to Borden and Madsen

(1949), on prune ESBM larvae began to

construct hibernaculae as fourth instars but

moulted during this process, and overwin-

tered as fifth instars. While the present

study supports the findings of Gilliatt

(1932), because no measures of variation

for the mean head capsule widths used to

categorize larvae have been provided by

any study, it is currently impossible to at-

tach complete certainty to any of these

results.

Validating the Linear Regression-

based Emergence Model. Using our lin-

ear regression model (Fig. 2), a 1 °C base

temperature, and 1 March to start DD ac-

cumulations, 50% of ESBM larvae were

predicted to appear by JD 87, 90 and 100

in 1992, 1994, and 1996, respectively.

Predicted dates for 50% emergence were 4,

10, and 6 d early, respectively (Table 2).

The mean (+ SD) error between predicted

and observed dates of 50% emergence was

-6.7 + 3.1 d. The number of DD; :c accu-

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004 23

Table 2.

Relationship between specific observed cumulative percentiles of emergence of overwintered

S. ocellana larvae, fruit-bud phenology of McIntosh apple trees and degree-day accumulations

above 1 °C (DD)»c) starting 1 March in 1992, 1994, and 1996.

Cumulative : Percentage of fruit buds at

Julian 1

emergence Year ante DD, °c each development stage

percentile Green tip Tight cluster Pink Blossom

1992 qi. 93.2 100

5% 1994 90 151.8 100

1996 98 140.7 100

1992 91 177.0 90 10

50% 1994 100 226.8 90 10

1996 =106 209.5 95 5

1992 106 OSie) 100

95% 1994 111 339.0 100

1996 115 276.3 10 90

1992 110 329.4 90 10

100% 1994 114 368.3 95 5

1996 121 320.1 70 30

'Percentage based on 20 fruit buds. Fruit-bud phenology based on B.C. Ministry of Agricul-

ture, Fisheries, and Food Tree Fruit Production Guide (1996)

mulating after 1 March to various percen-

tiles of observed emergence of larvae in

the field were calculated and shown to be

equally variable to 50% emergence (Table

2). Clearly our laboratory-derived linear

development model predicted median lar-

val emergence about 20% too early. This

deviance may arise because development

of ESBM larvae in spring may not be

solely related to temperature in the same

way life stages like eggs or pupae appear

to be (McBrien and Judd 1998). Alterna-

tively, overwintering larvae may have tem-

perature thresholds for movement or feed-

ing activity higher than the 7, we calcu-

lated from regression analysis (Fig. 2). If

this were the case, overwintering larvae

may have completed diapause or post-

diapause development by the dates pre-

dicted by the regression model, but if tem-

peratures were too low for them to move or

feed they may not have appeared on prun-

ings until temperatures were suitable. Ac-

cumulating DD before 1 March, when dia-

pause was likely over (Table 1), would

only have made the errors of prediction

greater, thus it seems a base temperature of

1 °C may be incorrect for predicting larval

activity in spring.

Observed DD Accumulations. The

CV associated with each observed DD

summation calculated using all possible

combinations of three starting dates (1

January, February or March) and 7; (1 - 8

°C) to describe observed 50% emergence

in the field is shown in Fig. 4. The lowest

CV for this one event was obtained with a

starting date of 1 January and 7; of 6 °C

(Fig. 4). This 7; is not unlike that of two

sympatric species of leafroller in the Pa-

cific Northwest, Pandemis pyrusana Kear-

foot and Choristoneura rosaceana Walker,

that have a 7; of =5 °C (Brunner 1991) and

emerge in spring after overwintering as

second- or third-instar larvae. The empiri-

cally-derived CV-based approach gave a

mean of 82.7 + 3.5 DDe-c from | January

to 50% emergence, with a CV of 4.3 (Fig.

4), whereas the mean number of DDj»¢

from 1 March to 50% emergence was

24 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

15 = sles ae .

] . =

Ao)

2 v

a) o

im)

5 Vv

ow iz

ro)

Go 5

bh on

v 1 January

1 2 3

|_|

|] |

v |

1 February | 1 March

5 6 7 8

Lower developmental base temperature (°C)

Figure 4. Coefficients of variation associated with three-year average (1992, 1994, and 1996)

degree-day summations from various starting dates (1 January, 1 February, and 1 March) to

50% observed emergence of overwintered larvae of S. oce/lana using different lower base tem-

peratures between | and 8 °C.

204.4 + 25.3 and more variable with a CV

of 12.4 (Fig. 4). To provide a methodol-

ogy for calculating DD¢-c indices associ-

ated with any percentile of observed emer-

gence in the field we plotted observed cu-

mulative larval emergence against DD6ec

accumulations after 1 January and a cumu-

lative Weibull function accurately de-

scribed (R? = 0.89, P < 0.05) this relation-

ship (Fig. 5). It should be noted that, al-

though this Weibull function described

observed emergence with less variation

than the laboratory-derived linear regres-

sion and | °C T;, (Table 2), the accuracy

with which this empirically-derived

nonlinear equation can predict future

events needs to be validated with inde-

pendent data. The difference between a 7;,

derived using this empirical approach and

the laboratory-derived DD model may be

explained partly by the difference in han-

dling of the prunings used to monitor lar-

val emergence in the laboratory at constant

temperatures and to monitor emergence in

the field. In the laboratory, prunings were

stored at 0.4 °C in total darkness for ca. 3

mo while prunings used to monitor emer-

gence in the field were removed from trees

ca. 10 d before larval emergence began

naturally. Factors besides thermal summa-

tions, such as light, chill units, or moisture

which trigger flower bud development,

may also determine when overwintering

ESBM larvae emerge. Any potentially

unknown factors that affect emergence are

inherently incorporated within any empiri-

cal model even if they are not understood.

For whatever reason, our data suggest a

developmental model generated from labo-

ratory data only, may not be suitable for

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

100 —

ap) =

c 75

O) ps

cD) ‘2

(ad) =

Cc _

O 50 —

ro)

(ok

cD)

25 -

—

O - ry,

25 50 res)

Best fitting nonlinear

Weibull function

100 125 150 175

Degree-day summations above 6 °C starting 1 January

Figure 5. Observed cumulative percent emergence of overwintered larvae of S. ocellana in

1992, 1994, and 1996 (data points). Solid line is best fitting (P < 0.05) cumulative Weibull

function (¥ = 100 x (1 - e “’”’)?* used to describe emergence where x = DDgvc after 1

January.

describing processes which trigger activity

of ESBM larvae during winter and their

appearance in spring. On the other hand

DD indices generated from observed field

data may prove useful in management of

ESBM (Fig. 5).

Phenology Models and Management

of ESBM. Median emergence of ESBM

larvae appeared to be closely linked to

fruit-bud phenology of McIntosh apple

trees (Table 2), occurring consistently at

the early, tight-cluster stage of fruit-bud

development. Currently, conventional

insecticide applications at tight cluster,

pink, or petal fall, or applications of Bacil-

lus thuringiensis (Berliner) at full bloom

which target leafrollers, are recommended

as indirect controls for ESBM in spring

(British Columbia Ministry of Agriculture,

Fisheries, and Food, 2004). The latter con-

trol is one most commonly used by organic

producers in the Okanagan and Simil-

kameen Valleys (Judd unpublished data).

During this study, emergence of ESBM

larvae was complete by early bloom,

which is very likely too late for control

because most larvae enclose themselves

within feeding shelters made from blos-

soms. Our observations indicate applica-

tion of residual insecticides to McIntosh

apples at the pink stage would have

reached 90 - 100% of the larvae (Table 2),

well before they enclose themselves in

feeding shelters. This is consistent with

observations by Madsen and Downing

(1968) that azinphosmethyl applied to

McIntosh apples in the early pink stage

provided good control of ESBM in spring.

However, recommendations to spray at

pink of McIntosh would not necessarily be

appropriate on apple varieties that flower

at different dates, which is a common oc-

26 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

currence 1n montane growing regions.

A temperature-based model that can

consistently predict 90 - 100% emergence

of overwintering ESBM larvae, independ-

ent of flowering dates, should have greater

application to different apple varieties,

years, regions and to host plants other than

apple. While this study has not yet pro-

vided that model, if the equation given in

Fig. 5 can be validated with independent

data then it may be useful in predicting any

percentile of larval emergence in spring

that is deemed necessary for control pur-

poses. Such an equation and models of

adult emergence, flight, and oviposition

during summer combined with a phero-

mone-based monitoring program (McBrien

and Judd 1998), may provide a more spe-

cific management programme for ESBM.

ACKNOWLEDGEMENTS

We thank G. Zilahi-Balogh, D. Benson,

T. Hansford for technical assistance, and

the following for financial support: Natural

Sciences and Engineering Council of Can-

ada, Agriculture and Agri-Food Canada,

Science Council of British Columbia, Brit-

Okanagan Valley Tree Fruit Authority,

Okanagan Similkameen Cooperative

Growers’ Association, British Columbia

Fruit Packers’ Cooperative, Similkameen

Okanagan Organic Producers’ Association,

and Phero Tech Inc.

ish Columbia Fruit Growers’ Association,

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J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004 29

Seasonal variation in recapture of mass-reared sterile

codling moth, Cydia pomonella (L.) (Lepidoptera:

Tortricidae): implications for control by sterile insect

technique in British Columbia

GARY J.R. JUDD', MARK G.T. GARDINER’ and HOWARD M.A.

THISTLEWOOD"”

ABSTRACT

In 1992, the Okanagan-Kootenay Sterile Insect Release (SIR) Programme was initiated

to eradicate codling moth, Cydia pomonella (L.), from montane, fruit-growing valleys in

British Columbia (BC), Canada. Excessive damage in 1994, and failures to maintain

sterile:wild (S:W) over- flooding moth ratios at 40:1, a target deemed necessary for

eradication, led to concern about activity of sterile moths and recommendations to sup-

plement control in spring. Using pheromone-baited wing traps and passive sticky pane

traps we monitored operational S:W ratios to determine if they continued to fall below

40:1 post-1994. Seasonal flight activity and recapture of sterile moths was compared

with that of wild moths from 7 May - 1 September, 1995 - 1999, in nine commercial

orchards in Cawston, BC. Mean weekly catches of wild males in pheromone traps, re-

flected first- (May) and second-generation (August) peaks of flight activity in orchards

supplemented with pheromone disruption, but only a single period of activity in insecti-

cide-supplemented orchards. Weekly catches of sterile moths in these same orchards

were always at their lowest in spring, and activity was correlated with seasonal air tem-

peratures. Yearly average S:W ratios in the insecticide-treated orchards ranged from

24:1 - 203:1 in 1995 - 1997. Examining S:W ratios using data from those weeks when

wild moths were actually caught, indicates ratios were frequently (29 - 91%) less than

40:1 in spring but S:W ratios fell below 40:1 less often during summer than spring.

Passive pane traps also revealed patterns of fewer sterile moth catches, and lower S:W

ratios in spring, compared with summer. Our data suggest low overflooding ratios con-

tributed to slower than predicted population reductions, and increased release of sterile

moths, of improved quality, between 1995 and 1997 did not significantly increase mean

weekly catches or S:W ratios in individual orchards in spring. Therefore, continued

application of supplemental insecticides, or a pheromone disruption treatment that re-

duced catch of moths, but did not significantly affect S:W ratios in spring, is recom-

mended. We conclude that similar analysis of trap data for the entire SIR Programme

(1994 - 2004) and correlations with damage would provide recommendations for the

best use of sterile insects as part of any future area-wide codling moth management pro-

gramme.

Key Words: Codling moth, sterile insect technique, flight activity, sterile:wild ratios

INTRODUCTION

In 1992, the British Columbia Fruit dollar Sterile Insect Release (SIR) Pro-

Growers’ Association and Regional Dis- gramme in the Creston, Okanagan and

trict governments launched a multimillion Similkameen Valleys of British Columbia

' Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland,

British Columbia, Canada VOH 1Z0

* Formerly: Okanagan-Kootenay Sterile Insect Release Board, 9848 Aberdeen Rd., Coldstream, B.C.,

Canada V1B 2K9

30 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

(BC), Canada with an objective to eradi-

cate codling moth, Cydia pomonella (L.),

from these montane, fruit-growing valleys

by 2000 (Dyck and Gardiner 1992). This

area-wide programme was the culmination

of 30 years of basic research, small imple-

mentation trials and much planning

(Proverbs 1971, 1982; Proverbs ef al.

1966, 1977, 1982; Dyck et al. 1993).

Originally the programme was divided

into three distinct phases: 1) Pre-release

Sanitation, 2) Sterile Moth Release, and 3)

Surveillance Monitoring and Protection.

During Phase 1 growers were required to

reduce wild codling moth populations to

levels resulting in 0.1 - 0.3 % damage at

harvest, considered equivalent to about 100

overwintering larvae per ha (Dyck ef al.

1993). Operationally, it was anticipated

these measures would equate to adult

populations of no more than two wild

moths per pheromone trap per week during

periods of peak emergence (Bloem and

Bloem 2000). In Phase 2, the programme

would make weekly releases of sterile

moths in all commercial orchards in order

to maintain sterile:wild (S:W) overflooding

moth ratios at 40:1, a target that extensive

research demonstrated was necessary to

eradicate populations in three years

(Proverbs 1971, 1982; Proverbs ef al.

1982). In Phase 3, an area-wide phero-

mone trapping programme would be 1m-

plemented post-2000 to prevent reinfesta-

tion of pest-free areas through early detec-

tion and targeted controls. These three

phases were to be implemented sequen-

tially in each of two zones. Zone 1, which

included the Okanagan from Osoyoos to

Summerland, Similkameen and Creston

Valleys, entered Phase 1 in 1992 and was

to recieve sterile moths under Phase 2 from

1994 - 1996. Zone 2 from Peachland to

Salmon Arm inclusive, was scheduled to

enter Phase | in 1995 and receive moths

from 1997 - 1999 (Dyck et al. 1993).

Following a two-year pre-release sani-

tation programme in Zone |, the first ster-

ile moths were released in May 1994. Al-

most immediately it was noted that weekly

S:W ratios from pheromone trap catches in

individual orchards were less than the 40:1

target. Unfortunately, in previous sterile

insect implementation trials in BC

(Proverbs 1982; Proverbs ef al. 1966,

1977, 1982; ), codling moth S:W ratios

were almost always presented as averages

for regions, generations or seasons. These

coarse-grained values made it difficult to

know what ratios should be expected on a

weekly basis in individual orchards and

whether there should be concern for the

long-term control effort. In this regard,

similar implementation trials in Washing-

ton state (White et al. 1976) showed that

S:W ratios within a single 130-ha orchard

ranged from 54:1 to 938:1 when all traps

were averaged over the season, but when

examined individually, 21 of 38 total traps

showed at least one weekly ratio that was

less than 20:1. Furthermore, 78% of all

codling moth damage was found within

152 m of these 21 traps. Therefore, to

achieve area-wide population reduction

and suppression of codling moth in a fruit-

growing region like BC, where there are

numerous, small, noncontiguous orchards,

it is important to maintain appropriate S:W

ratios in individual orchards and traps,

especially during periods of peak emer-

gence of wild moths. Any critical assess-

ment of the annual progress or success of a

sterile insect programme in BC should be

based on an analysis that reveals the extent

to which appropriate S:W ratios are being

achieved in individual sites and presented

as a proportion of all orchards being

treated.

Our original objectives in this study

were to document operational S:W ratios

in several orchards in an effort to deter-

mine whether they were falling below the

40:1 target after 1994, and if so, to deter-

mine the extent to which inadequate ratios

were resulting from large wild populations,

thus justifying need for supplemental con-

trols, or were resulting from poor recapture

of sterile moths. A further rationale in

publishing these data now, is that these

data and analyses of this type are needed to

make objective decisions about the design

of a sustainable area-wide codling moth

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

control programme post-2005 (Dendy ef

al. 2001). Our analyses may be useful in

making decisions on the best uses of sterile

codling moths in BC and other parts of the

world where application of this technique

is currently being considered.

MATERIALS AND METHODS

Test Sites and Sterile Insect Delivery.

Studies were carried out in four conven-

tionally- and five organically-managed

apple orchards in Cawston, BC, located in

the Similkameen Valley, within Zone 1 of

the Okanagan-Kootenay SIR Programme

(Dyck et al. 1993). Orchards ranged in

size from | - 3 ha and were composed of

mixed ‘McIntosh’, ‘Spartan’, ‘Delicious’

and ‘Golden Delicious’ apple varieties

planted at densities of 600 - 900 trees / ha

with tree x row spacings of 2.4 - 4.6 x 4.6 -

5.5 m, respectively. Orchards were chosen

because of their known history (Judd ef ai.

1996, 1997) and because they were part of

the original sterile insect implementation

trials conducted by Proverbs et al. (1982).

While our trials were being conducted,

conventional growers were asked to apply

insecticidal controls during flight of first-

generation adult codling moths in May and

June, which most growers did in 1995 -

1997 (Bloem and Bloem 2000). Organic

growers did not apply insecticides, but

they supplemented release of sterile males

by applying Isomate-C and Isomate CM/

LR (Pacific Biocontrol Corp., Vancouver,

Washington, USA) in 1995 - 1996 and

1997 - 1999, respectively, at a rate of 500 -

1000 dispensers / ha, as pheromone treat-

ments to disrupt mating of wild codling

moths (Judd et al. 1996, 1997; Judd and

Gardiner 2004). Pheromone treatment was

required because organic growers did not

want to lose certification by applying con-

ventional insecticides. This application

presented an opportunity to determine

what impact a pheromone-based mating-

disruption treatment might have on flight

activity of sterile moths and S:W ratios.

The original plan was to deliver 1000

mixed-sex sterile codling moths in each ha

of orchard two times each week (Dyck ef

al. 1993). However, Bloem and Bloem

(2000) stated that on average orchards

were receiving 2250 moths / ha / week in

1994, and as many as 3750 moths / ha /

week in 1997, although it is not clear

whether these numbers refer to mixed-sex

moths, or males only. Exactly how many

sterile moths reached our study orchards is

unknown, but all orchards were visited

twice weekly by the same release drivers

throughout each year and therefore, should

have received similar numbers of moths.

Beginning in late April or early May and

continuing until mid-September, moths

were distributed in every fifth or ninth row

of orchard approximately 25 - 30 m apart.

Chilled moths irradiated as described by

Bloem and Bloem (2000) were dispensed

by gently blowing them onto the ground

beneath trees from a small hopper and fan

unit (McMechan and Proverbs 1972)

mounted on the front end of an all-terrain

vehicle (Bloem and Bloem 2000).

Monitoring Codling Moth Seasonal

Flight Activity. From 1995 through 1999,

seasonal flight activity and capture of ster-

ile and wild male codling moths was as-

sessed using pheromone-baited traps. Two

to six Pherocon 1-CP style, sticky wing

traps (Phero Tech Inc., Delta, BC) baited

with the codling moth sex pheromone

codlemone, (£,E£)-8,10-dodecadien-1-ol

(99% isomerically pure, Shin-etsu, Fine

Chemicals Division, Tokyo, Japan) were

used in each orchard. A minimum of two

traps and a maximum of two traps per ha

were used in each orchard. Traps were

hung ca. 1.5 - 2.0 m above ground near the

centre of each orchard on 7 or 8 May

(Julian Day 128) and were checked weekly

until 1 September. Trap positions re-

mained fixed within orchards across sea-

sons. Trap bottoms were replaced weekly

and pheromone baits were changed every

third week. Sterile codling moths were

identified by an internal red dye seques-

tered from the artificial diet on which they

a0 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

were reared (Brinton ef al. 1969).

All pheromone lures were prepared by

dispensing a 200 ul solution of codlemone

dissolved in dichloromethane solvent into

wells of red rubber septa (Aldrich Chemi-

cal Company Inc., Milwaukee, Wisconsin,

USA). After loading, septa were air dried

for 18 h at 23 °C in a fume hood and stored

at 0 °C until pinned to the inner side of trap

lids in the field. Septa used in conven-

tional orchards were loaded with 1 mg of

codlemone and septa used in pheromone-

treated orchards were loaded with 10 mg

of codlemone because the former are less

attractive in Isomate-treated orchards (Judd

et al. 1996).

In 1996, catches of sterile and wild,

male and female codling moths were also

monitored using passive pane _ traps

(Weissling and Knight 1994) to measure

relative activity of sterile and wild moths

independent of response to pheromone

lures. Pane traps consisted of vertically-

oriented, semirigid, clear acetate plastic

squares (30 x 30 cm) that were coated with

STP oil treatment (First Brands Corpora-

tion, Scarborough, Ontario, Canada) to

capture alighting insects. Sticky panes

were clamped 3 m above ground to an up-

right iron rod abutting tree trunks. Eight to

30 pane traps were deployed evenly in a

grid pattern throughout each orchard. Due

to their cumbersome nature and need for

frequent maintenance, pane traps were

only used in 1996 and were placed in the

field every other week, and only for a

three-day sampling interval,

through Thursday.

Orchard Temperatures. Hourly air

temperatures throughout this study were

recorded at a centrally-located orchard in

Cawston, BC from 1 May through 1 Sep-

tember each year. Temperature readings

were made using a two-channel DP-212

Datapod (OmniData™, Logan, Utah,

USA) housed in a 1 m_ high Stevenson

screen. Daily degree-day (DD) summa-

tions above a 10 °C developmental base

temperature and below a 31 °C upper de-

velopmental threshold were calculated by

fitting a sine wave (Allen 1976; case 4) to

daily air temperature minima and maxima

using the computer program described by

Higley et al. (1986).

Data Analyses. Codling moth catches

in all traps within an orchard were summed

each week. Median catches per trap per

orchard in each generation and year were

compared using a Kruskal Wallis non-

parametric analysis of variance followed

by Dunn’s multiple comparisons test for

ranked data (Zar 1984). Some paired fre-

quency data were analyzed using Fisher’s

exact test and y° tests where appropriate.

Regression analyses was used to relate

weekly and seasonal catches to tempera-

ture. All statistical tests were performed

using SigmaStat® (Version 3.0.1, SYSTAT

Software Inc., Richmond, California,

USA) and an experimental error rate of a =

0.05.

Tuesday

RESULTS

Flight Activity of Wild Moths. Mean

weekly catches of wild codling moths in

conventional insecticide-treated orchards

in 1995 - 1999 peaked at 12, 4.5, 0.75, 0.4

and 0.2 moths / trap / week during the first

four weeks of each trapping season, re-

spectively (Fig. 1A). Catches of wild

moths in insecticide-treated orchards were

always lower in the second half of the sea-

son (Fig. 1A) and near zero after 1996.

Catches of early-season, first-generation

wild moths however continued into 1999

(Fig. 1A). After 1996, catches of wild

moths in insecticide-treated orchards never

went above the anticipated maximum

threshold of 2 wild moths / trap / week,

and during the five-year monitoring period

they were less than this threshold 97.5% of

the time.

In contrast to insecticide-treated or-

chards, trap-catch curves in pheromone-

treated orchards reflected both first- and

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

second-generation peaks of wild moth

flight activity in 1995 and 1996 (Fig. 1B).

Total catches in the second half of 1995

were even greater than the first half. How-

ever, after 1996, catches of wild codling

moths were extremely low under phero-

mone-treatment and no wild moths were

caught in any pheromone-treated orchard

in 1999 (Fig. 1B).

Flight Activity of Sterile Moths. <A

plot of mean + standard error (SE) weekly

catches of sterile moths from 1995 - 1999

in conventional insecticide-treated or-

chards reveals a pattern of low catches

during the early season and increasing

catches later in the season (Fig. 2). Mean

Mean Number of Wild Moths Caught / Trap / Week

Pheromone-treated |

catches of sterile moths in the first two

weeks of the season (Fig. 2) were often

below the 40 moths / trap / week needed to

ensure a 40:1 S:W ratio if only a single

wild moth were caught. On average, it was

not until week 8 that catches were consis-

tently greater than 80 moths / trap / week

needed to ensure a 40:1 S:W ratio if the

programme threshold of 2 wild moths /

week were reached. There was a signifi-

cant linear ( r 7 = 0.87, P < 0.05) increase

in weekly catches of sterile males in weeks

1 - 8, but catches over the entire season

were described more accurately ( R° =

0.93, P< 0.05) by a sigmoid curve (Fig. 2).

Increasing catches in weeks | - 8 were

Figure 1. Mean weekly catches of wild male codling moths in pheromone-baited wing traps in

insecticide-treated conventional (A) and pheromone-treated organic (B) apple orchards under

management of the Okanagan-Kootenay SIR Programme from 1995 - 1999, in Cawston, BC.

n= 4 conventional and 5 organic orchards and 2 - 6 traps / orchard.

34 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

~ 200

oO)

a=]

iq]

2 160

ia?)

= 120

eee

ad}

Ww 40

= 0

Insecticide-treated ®

Pheromone-treated

160

120

8 10 12 14 16

Weeks

Figure 2. Comparison of mean (+ SE) weekly catches of sterile male codling moths in phero-

mone-baited wing traps in insecticide-treated conventional (bars) and pheromone-treated or-

ganic (dots) apple orchards under management of the Okanagan-Kootenay SIR Programme

from 1995 - 1999, in Cawston, BC. Curves represent nonlinear regression lines fitted to mean

catches in insecticide- (124.7 / [1 + e ~°~7/')) and pheromone-treated orchards (32.2 / [1 +

e —(x - 7.72) / aly

correlated ( r = 0.661, P < 0.05) with con-

current seasonal increases in mean weekly

temperatures.

Although weekly catches of sterile

moths in pheromone-treated orchards were

reduced significantly (ca. 78%) over

catches in insecticide-treated orchards,

they revealed a similar pattern of low early

season catches that increased as the season

progressed (Fig. 2). Catches of sterile

males regularly reached as many as 40

moths / trap / week after week 9. Again,

while there was a significant linear ( r * =

0.641, P < 0.05 ) increase in catches of

sterile males in pheromone-treated or-

chards during weeks | - 8, catches over the

entire season were better described ( R ? =

0.83, P< 0.05) by a sigmoid curve (Fig. 2).

The median number of sterile moths

caught in conventional orchards varied less

among years than between generations

within years (Table. 1). There was no sig-

nificant difference (Dunn’s test a = 0.05)

in the median number of sterile moths

caught during weeks 1 - 8 in 1995, 1996,

1997 and 1999 (Table. 1). In 1998 how-

ever, significantly more sterile moths were

caught, mean temperatures were higher,

and more DDjo°-c accumulated during the

first eight weeks of the season than any

other year (Table 1). In each of the five

years, median trap catches in weeks | - 8

(first generation) were less than median

catches in weeks 9 - 16 (second genera-

tion). In each year, the ratios of second-

generation to first-generation median trap

catches were significantly (P < 0.05) dif-

ferent than an expected 1:1 ratio under a

null hypothesis of equal probabilities of

catch (Table 1), and over five years sterile

moths were 3.9-fold more likely to be

caught in second than in first generation.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004 35

Table 1.

Median number of sterile male codling moths caught per trap per week and degree-day (DD)

accumulations during first- and second-generation wild moth flight activity and median yearly

catches and sterile:wild (S:W) overflooding moth ratios in four insecticide-treated conventional

apple orchards receiving sterile codling moths under management of the Okanagan-Kootenay

SIR Programme, in Cawston, BC, 1995 - 1999.

Adult generation!”

: Sse ety Median Yearly S:W

y First Second trap catch | flood

car (weeks 1-8) —__ (weeks 9 - 16 ratios? er ae ng

10S

Catch DD orc Catch DDo°c Second / First

1995 27.4a 463 53.2a 584 1.9 * 40.3a 24

1996 42.7a 339 175.1 b 674 4.1% 108.9b 139

1997 37.9a 427 72.0 a 611 1.9 * 56.4a 203

1998 112.9b 512 204.9 b 757 1.8 * 158.9b 794

1999 65.3a 374 168.5 b 653 2.6 * 116.9b 213

1995-1999 42.7 423 168.1 656 3.9 * 108.9 287

'Trap-catch medians for a generation within a column followed by different letters are signifi-

cantly different (Dunn’s test a = 0.05) following a significant (P < 0.05) Kruskal-Wallis Test.

> DDyoxc totals above 10 °C accumulated for first generation from Julian Day 128 - 184 and for

second generation from Julian Day 185 - 241.

* Asterisks indicate trap-catch ratios are significantly different (P < 0.05) from 1:1 by a’ test

on actual trap catches.

Sterile: Wild Moth Ratios. S:W ratios

presented as yearly averages for all or-

chards suggest overflooding ratios were

well above 40:1 in all years except 1995

(Table 1), steadily increasing from 1995 -

1998. However, restricting analysis of

S:W ratios in the insecticide-treated or-

chards to those weeks when wild moths

were actually caught (Table 2), indicates

ratios during the first eight weeks of the

season were less than 40:1, 91% of the

time in 1995 (21 of 23 orchard-weeks),

60% in 1996 (9 of 15 orchard-weeks), and

29% in 1997 (2 of 7 orchard-weeks).

Closer examination of S:W ratios in these

orchards shows that during the first four

weeks of the trapping season, when wild

catches peaked (Fig. 1A), S:W ratios never

reached 40:1 in 1995, did so once in 1996

and only twice in 1997. In one of the three

orchards where wild moths were caught in

1998 (Table 2), S:W ratios fell below 40:1

in both weeks this occurred. It was not

until 1999, when wild catches were near

zero (Fig. 1A), that a 40:1 S:W ratio was

achieved in all orchards during the first

eight weeks of the season (Table 2). Simi-

lar analysis performed in the second half of

the season indicates S:W ratios fell below

40:1 about 39% of the time over the five

years (9 of 23 orchard weeks), which was

significantly less often than during the first

eight weeks (Table 2).

S:W ratios in pheromone-treated or-

chards were only analyzed for 1995 and

1996 because few or no wild moths were

caught in these orchards in 1997 - 1999

(Fig. 1B). In spite of yearly reductions

(4.5-fold) in catches of sterile moths in

pheromone-treated relative to insecticide-

treated orchards (Fig. 2), S:W ratios during

the first eight weeks of 1995 were similar

in both sets of orchards (Fig. 3A-B). This

similarity was surprising because in most

weeks, wild catches were greater in phero-

mone- than in insecticide-treated orchards

where wild catches went above 2 moths /

trap / week only once. While S:W ratios in

pheromone-treated orchards never went

above 40:1 during flight of first-generation

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

Table 2.

Frequency of weeks during the first (weeks | - 8) and second generation (weeks 9 - 16) of wild

codling moths when sterile:wild ratios in pheromone-trap catches were less than 40:1

(numerators) for those weeks when wild moths were caught (denominators) in each of four

insecticide-treated conventional orchards receiving sterile codling moths under management of

the Okanagan-Kootenay SIR Programme, in Cawston, BC, 1995 - 1999.

Adult Orchards Yearly Fisher’s

Year Boece frequency Exact Test

8 I - 3 4 totals P-value!

ist 5/5 7/8 5/5 4/5 98

12) gnd 1/2 3/6 1/2 3/4 8/14 0.0345

is 2/2 1/5 2/3 4/5 9/15

1996 and 0/1 1/4 0/0 0/4 1/ 9 0.0333

607 ist 0/0 2/4 0/1 0/2 DP

and 0/0 0/0 0/0 0/0 0/ 0 ~

ook ist 0/0 0/3 2/2 0/2 oe ee

and 0/0 0/0 0/0 0/0 0/ 0 =

a6 1st 0/0 0/0 0/0 0/0 0/ 0

and 0/0 0/0 0/0 0/0 0/ 0 :

Orchard ist FIR. A0s20 9/11 8/14 34/52 re

totals gnd 1/3. + +4/10 if 2 3/ 8 9/23

'Fisher’s Exact Test (2 x 2 contingency table) of the null hypothesis of equal frequencies in

each generation during which the sterile:wild ratios are < 40:1 using yearly frequency totals

from all orchards. ns = P > 0.05

wild moths in 1995 (Fig. 3B), they were

only marginally better in the insecticide-

treated orchards where ratios reached 40:1

once (Fig. 3A). Note however, this one

occurrence was in the week when wild

moths were near their lowest, and followed

a week when catches of wild moths peaked

but catches of sterile moths inexplicably

dipped (Fig. 3A). S:W ratios in phero-

mone-treated orchards fell below 40:1

most of the second half of 1995 (Fig. 3B)

because catches of wild moths increased.

Late-season increase in wild-moth activity

in these orchards may be caused by using

more attractive 10 mg lures and waning

effects of pheromone disruption dispens-

ers. This apparent increase in activity of

second-generation wild moths was a tem-

porary aberration in pheromone-treated

orchards. Over five years, total seasonal

catches of wild moths declined faster in

pheromone-treated orchards than they did

in the insecticide-treated orchards (Fig. 1).

Pane Traps versus Pheromone Traps.

Catches in pane traps from individual or-

chards were too low to show any signifi-

cant weekly patterns or conduct any mean-

ingful statistical analyses on catches of

either sterile or wild codling moths, so

catches were pooled across orchard treat-

ments. S:W ratios on pane traps in weeks

1 - 8 (first generation) are compared to

those in weeks 9 - 16 (second generation)

and ratios on pane traps are compared with

those reflected by pheromone trap catches

(Fig. 4). In the insecticide-treated orchards

(Fig. 4A) catches in pane traps reflect the

same pattern as pheromone traps, low S:W

ratios were observed in weeks | - 8 and

higher S:W ratios in weeks 9 - 16. S:W

ratios on pane traps increased 6.2-fold

while those in pheromone traps only in-

creased 4.8-fold across generations (Fig.

4A), suggesting activity-driven responses

to the former were more important than

increased pheromone responses to the lat-

ter.

In pheromone-treated orchards (Fig.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Wild Catches

Insecticide-treated 1995

120

Target S:W Ratio = 40'1

io)

’

preyvutuyuda td

Pheromone-treated 1995

120

Mean Weekly S:W Overflooding Moth Ratio

Target S:W Ratio = 40:1 ¥

er |

peur tit pit

Mean Number of Wild Moths Caught / Trap / Week

HE |

S ALB eats

0 2 4 6

ee a

14 16

Weeks

Figure 3. 1995 mean weekly catches of wild male codling moths and sterile:wild moth ratios

in pheromone-baited wing traps in insecticide-treated conventional (A) and pheromone-treated

(B) organic apple orchards under management of the Okanagan-Kootenay SIR Programme, in

Cawston, BC. n= 4 conventional and 5 organic orchards and 2 - 6 traps / orchard.

4B) catches with both pane traps and

pheromone traps once again reflect the

established pattern of low S:W ratios in

weeks | - 8 and higher ratios in weeks 9 -

16. However, in pheromone-treated or-

chards S:W ratios on pane traps showed

the same cross-generation increase (2.1-

fold) as pheromone traps (2.3-fold), re-

flecting suppression of sterile male re-

sponse to pheromone-baited traps in or-

chards under pheromone-based mating

disruption (Fig. 2), which artificially limits

ratios.

Catches of females on pane traps were

too low to ascribe any specific seasonal

pattern in their response.

DISCUSSION

Decades of research examining use of

sterile insect technique to control codling

moth have identified the need to maintain

40:1 S:W overflooding moth ratios in order

to achieve population reduction, and have

further emphasized the importance of do-

ing this during the first generation because

the reproductive potential of the species is

lowest at this time of year. Our detailed

examination of seasonal flight activity and

recapture of male codling moths in nine

commercial orchards under management

by sterile insect release showed significant

within-season variation over five years,

often resulting in S:W ratios less than 40:1.

Low S:W ratios were most pronounced in,

but not restricted to, the first eight weeks

of the trapping season from May through

June (Fig. 3; Table 2), the period of wild-

moth activity referred to as first generation

(Madsen and Procter 1985).

In this study, catches of first-generation

wild moths generally peaked during the

first four weeks of the season in late May

38 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

ian Weeks 1-8

1** Generation

A. Insecticide-treated 1996

—_ S i

Pane Pheromone

Trap Type

Mean + SE Sterile : Wild Moth Ratios

(an)

Weeks 9 - 16

2? Generation

B. Pheromone-treated 1996

100 ~

40 ee | as

Pheromone

Trap Type

Figure 4. 1996 mean (+ SE) sterile:wild moth ratios from catches in pheromone-baited wing

traps and sticky pane traps during first- (weeks 1 - 8) and second-generation (weeks 9 - 16)

flight-activity periods for wild moths in insecticide-treated conventional (A) and pheromone-

treated organic (B) apple orchards under management of the Okanagan-Kootenay SIR Pro-

gramme, in Cawston, BC. n = 4 conventional and 5 organic orchards and 2 - 6 pheromone

traps and 8 - 30 pane traps / orchard.

or early June (Fig. 1A-B) and when it oc-

curred, second-generation catches peaked

in weeks 11 - 12 during early August (Fig.

1B). In contrast, catches of sterile moths

(Fig. 2) were at their lowest in the first four

weeks of the season, increasing thereafter

and reaching a plateau around week 10 in

July. The observed sigmoid pattern (Fig.

2) in recaptures of sterile moths might be

explained by a combination of factors: (1)

released moths that live longer than a week

may accumulate with subsequent weekly

releases, (2) there may be greater mortality

of sterile moths in spring perhaps because

of more frequent application of insecti-

cides or cooler temperatures, (3) sterile

moths may be less responsive to phero-

mone traps in spring than summer, (4) ster-

ile moths may be less active under cool

spring temperatures than they are in sum-

mer, or (5) trap catches may be limited in

summer because trap bottoms become

saturated with moths reducing apparent

late season activity. Whatever the cause(s)

it seems likely this seasonal pattern is in-

herent to activity of sterile moths because a

similar pattern was observed in both insec-

ticide- and pheromone-treated orchards,

where the latter received no pesticides and

where traps never became saturated in

moths (Fig. 2).

Response to temperature likely explains

much of this seasonal variation because the

greatest number of sterile moths was

caught in 1998 (Table 1), the warmest

spring in this five-year study, and a signifi-

cant linear correlation was found between

mean weekly catches and mean tempera-

tures. S:W ratios in catches on passive

pane traps were also greater during weeks

9 - 16 compared with weeks 1 - 8 (Fig.

4A), lending support to the idea that sterile

moths are simply less active than wild

moths in cool spring weather (Bloem and

Bloem 1996; Bloem et a/. 1998). The lack

of any significant difference in spring-time

S:W ratios in pheromone- and insecticide-

supplemented orchards when measured by

pheromone traps (compare Fig. 4A and

4B), is further indication of a seasonal dif-

ference in activity. Catches of sterile

moths are suppressed by pheromone treat-

ment in summer (Fig. 2) and this reduces

S:W ratios relative to insecticide-treated

orchards when measured using pheromone

traps during weeks 9 - 16 (compare Fig.

4A and 4B). In spring the opposite occurs.

Activity of sterile moths as evidenced by

catches in the insecticide-treated orchards

(Fig. 2) is already low in spring. There-

fore, full expression of disruption is not

seen in spring and S:W ratios are more

similar in pheromone- and_insecticide-

treated orchards when measured using

pheromone traps (compare Fig. 4A and

4B).

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

Inactivity of sterile moths may be an

artifact of laboratory-rearing conditions.

Proverbs (1971) stated, although no data

were presented, that moths reared at high

constant temperatures, as they are in the

current SIR Programme (Bloem and

Bloem 2000), are less active in spring than

wild moths, and males reared at constant

temperatures are apparently less responsive

to synthetic pheromone than males reared

under fluctuating temperatures, especially

in spring (Proverbs 1982). Hutt (1979)

confirmed that recapture of sterile codling

moths in pheromone traps increased after

insects were reared at fluctuating tempera-

tures. However, Bloem ef al. (1998) did

not see an affect of fluctuating rearing con-

ditions on pane-trap catches in spring and

they saw greater catches in pheromone

traps in fall than in summer, even though

dusk temperatures were cooler in fall.

These apparent contradictions suggest ad-

ditional factors may be at work. Whether

temperature impacts flight activity of ster-

ile moths directly, or indirectly through

rearing, or somehow modulates their re-

sponse to pheromone sources remains to be

determined. It should be noted that mass-

rearing of sterile moths under fluctuating

temperature regimes was tested but

deemed impractical in the current Osoyoos

rearing facility (Bloem ef a/. 1998).

When the SIR Programme was de-

signed and production capabilities of the

rearing facility were considered (Dyck ef

al. 1993), it was calculated that production

and release should be able to ensure 40:1

overflooding ratios if the Pre-release Sani-

tation phase could reduce populations of

wild codling moth to levels resulting in no

more than 0.1- 0.3% harvest damage. It

was assumed this level of damage would

result in no more than 2 wild moths / trap /

week / orchard and initial release numbers

were generated around this threshold

(Bloem and Bloem 2000). Assuming

catches in pheromone traps reflect opera-

tional ratios of sterile and wild moth popu-

lations, traps need to show catches of 80

sterile males / trap / week, if the SIR Pro-

gramme is going to maintain 40:1 ratios

when wild populations are this large. Our

data show that during the first eight weeks

of the season this target was only achieved

in 1998. These data strongly suggest

populations of wild moths should be re-

duced to levels resulting in no more than 1

wild moth / trap / week at peak flight to

ensure S:W ratios are consistently at or

above the 40:1 target during spring.

Alternatively, if wild populations are

not reduced, 40:1 S:W ratios might be

maintained by releasing more sterile moths

when wild populations are reaching 2

moths / trap / week. Intuitively, this

sounds like a reasonable approach but our

analysis suggests it may be questionable in

spring. For example, recaptures of sterile

moths released in 1995 and 1997 were not

significantly different in either generation

(Table 1). This is surprising because the

SIR Programme reportedly released 1.7

times more sterile moths in 1997 than

1995, and fewer insecticides were applied

against codling moth in 1997 than in 1995.

With catches of sterile moths averaging

37.9 / trap / week during first generation in

1997, the best that might have been

achieved was a 19:1 S:W ratio if 2 wilds /

trap / week were caught. At this level of

wilds even median catches in summer

1997 (Table 1) would not have produced

an overflooding ratio of 40:1. These ob-

servations strongly suggest that increasing

production and release of sterile moths in

1997 had no demonstrable impact on re-

capture of sterile moths in our study or-

chards, particularly in spring, and these

increases would rarely have resulted in

adequate S:W ratios in individual orchards

unless wild populations were reduced well

below 2 moths / trap / week.

As a caveat, it should be noted that

more sterile moths were produced and re-

leased in 1997 than in 1995, but there are

no records to verify the number of moths

release drivers delivered to any particular

orchard. It can also be argued that opera-

tional S:W ratios might have appeared

larger in this study had we used a trap

which was less susceptible to saturation

with sterile moths than small wing traps.

40 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

However, while trap saturation may play a

role in the plateau seen on catch curves in

summer (Fig. 2), which conceivably places

upper limits on S:W ratios, trap saturation

was never an issue in spring, nor on pane

traps, nor in pheromone-treated orchards

showing the same trends. One of the rea-

sons we used wing traps was because these

traps were the standard for the operational

programme being assessed.

In spite of suboptimal S:W ratios, mean

seasonal catches of wild moths declined

from 1995 - 1999 in orchards receiving

sterile moths and supplemental insecticides

in spring. After three years, second-

generation moths were almost undetectable

(Fig. 1A). Ignoring the few late-season

catches of moths in 1998 and 1999 as re-

sulting from outside sources like wooden

apple bins (SIR Programme, unpublished

data), an apparent disappearance of sec-

ond-generation codling moths by 1997

(Fig. 1A), combined with maintenance of

S:W moth ratios greater than 40:1 during

weeks 9 - 16 throughout 1996 - 1997

(Table 2), supports the view that it is possi-

ble to eliminate summer populations of

codling moths within three years in local-

ized areas. The difficulty comes in sepa-

rating the cause(s) of this population de-

cline. It seems likely that intensive insecti-

cide application during first generation

(Bloem and Bloem 2000) was critical in

achieving this result. Insecticides applied

against first-generation larvae will un-

doubtedly reduce resulting adult popula-

tions in second generation, especially when

this is done on an area-wide basis as it was

during this study. The potential for immi-

gration of background wild populations

was probably greatly reduced by this area-

wide approach to spraying and other clean-

up procedures. The effect of these insecti-

cides is probably the reason why traps in

conventional insecticide-treated orchards

revealed little or no second-generation

wild moth flight activity in 1995 and 1996,

but in pheromone-treated orchards there

was a relatively large second-generation

catch in 1995 (Fig. 1A-B). It seems diffi-

cult to argue that observed reductions in

second-generation wild moths (Fig. 1A)

would have more to do with suboptimal

S:W ratios in spring, than with insecticide

applications. Likewise, providing evi-

dence that large S:W ratios during sum-

mers of 1997 - 1999 had more to do with

increasing catches of sterile moths (Fig. 2),

than it did with the absence of a second-

generation of wild moths (Fig. 1A), is dif-

ficult. This being the case, it may make

more economic sense to apply insecticides

during first generation and only release

moths during the second generation.

In spite of extensive spraying, five

years of moth release (1994 - 1998), and

S:W ratios during second-generation that

were always above 40:1 in 1997 and 1998

(Table 2), first-generation moths persisted

into 1999 in the insecticide-treated or-

chards. These data are similar to results

reported for Zone 1 as a whole, where av-

erage trap captures for all orchards showed

great reductions in the second generation

in 1995, and persistence of a small first

generation through 1997 (Bloem and

Bloem 2000). Further evidence of this

persistence came from 1500 Zone-1 or-

chards sampled in 1999 using cardboard

tree bands (Judd et al. 1997), which found

that 15% still had overwintering codling

moth larval populations going into 2000

(HMAT, unpublished SIR Programme

data). It appears a small portion of the

larval population arising from _first-

generation mating can escape control by

insecticides in spring and sterile insect

technique in summer. We hypothesize that

early-emerging univoltine larvae not killed

by insecticides in spring, and diapausing in

summer because they are univoltine, could

potentially escape both controls. Studies

of the degree to which diapause and voltin-

ism may affect predictions of eradication

or long-term management of codling moth

populations are warranted, especially as

efforts to release sterile insects move fur-

ther north in BC where a greater degree of

early diapause is anticipated.

Predictions of eradication of codling

moth from Zone 1 by 1996 (Dyck eft al.

1993) and subsequent predictions by 1999

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

(Bloem and Bloem 2000) were not real-

ized. Our data suggest that low S:W over-

flooding ratios during spring may have

contributed to a slow rate of population

decline. Several studies have emphasized

the point that sterile males have their great-

est impact on reproduction of codling moth

in first generation (Proverbs ef a/. 1966;

Proverbs 1971). In studies where codling

moth population reduction has clearly been

demonstrated using sterile insect technique

(Proverbs et al. 1966, 1977; Proverbs et al.

1982), the authors report it was rare for

S:W ratios to fall below 40:1, at anytime

during the season. Inadequate spring-time

ratios in the BC SIR Programme, means

control is largely exerted against one gen-

eration each year. Controlling three gen-

erations instead of six over a three-year

period, likely doubles the time required for

eradication from 3 - 6 years, which seems

consistent with reported progress (Bloem

and Bloem 2000). Within-season and be-

tween-orchard variation in S:W ratios was

not revealed by average yearly overflood-

ing ratios (Table 1), a coarse-grained sta-

tistic often used in sterile insect pro-

grammes. These summary type ratios are

artificially inflated by summing catches of

sterile moths during periods of the season

when there are no wilds, thus giving a mis-

leading impression of the control effort

being achieved. This type of reporting

may not be applicable in an area-wide pro-

gramme where there are many, small, non-

contiguous orchards and wild populations

to be eliminated.

If eradication were to be a goal of any

SIR programme against codling moth, then

efforts must include continued use of in-

secticides in spring, or reduction of early-

season reproduction by means other than

sterile moths. In choosing supplemental

controls it must be noted that while apply-

ing insecticides during first generation

obviously increases larval mortality, it also

kills sterile moths, or potentially impairs

their pheromone response (Linn and

Roelofs 1984; Haynes and Baker 1985).

Biological insecticides like Virosoft-CP4",

a commercial granulovirus product may be

useful because they act on larvae and not

adult moths. Our results suggest applica-

tion of pheromone-disruption treatments

against first-generation moths may also be

very useful in augmenting control by ster-

ile insects, especially in organic orchards.

Although codling moth was not eradi-

cated in BC and progress was slower and

more costly than anticipated, it was re-

duced to sub-economic levels in most

Zone-1 orchards by 2001. Reliance on

sterile insect technology seems capable of

keeping damage below economic levels

but there is some question about financial

sustainability (Dendy ef a/. 2001). When

much of the expenditure in a typical SIR

programme is on rearing and releasing

moths, the moths must be used effectively.

In our analysis, we have focussed on a

ratio of 40:1, because all previous work

suggested this was necessary for eradica-

tion. However, it appears that ratios less

than 40:1 can stabilize but not eliminate

populations, and provide some suppression

rather than eradication. The key question

for management then becomes what ratios

are acceptable in that new context.

An analysis of the SIR Programme

trapping data from 1994 - 2004, on an indi-

vidual orchard basis, within a spatial con-

text, may provide insight on the S:W ratios

providing suppression. If historic opera-

tional S:W overflooding ratios were corre-

lated with damage data, analysis may re-

veal why the programme has worked in

some orchards and areas, and not 1n others.

Such analysis may also provide a more

realistic appraisal of any codling moth SIR

programme and would compliment the

detailed observations we have made on a

subset of orchards. This type of analysis

will also be useful in planning the best use

of sterile codling moths in BC, and other

parts of the world where this technique is

currently being considered.

42 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

ACKNOWLEDGEMENTS

We thank the Similkameen-Okanagan

Organic Producers' Association (SOOPA)

and its cooperating members for allowing

us to conduct trials in their orchards and

Jule Boulé, Lila DeLury, Janine Gartrell,

Karen Todd, Nicole Verpaelst and Nicole

Weremy for their technical assistance. The

Okanagan-Kootenay SIR Board provided

Director, 1998 - 2001, and GJRJ was Chair

of the Technical Advisory Committee,

1998 - 2000. This research was partially

funded by SOOPA, U.S. Department of

Agriculture, Washington State Tree Fruit

Research Commission and the Agriculture

and Agri-Food Canada Matching Invest-

ment Initiative.

unpublished data; HMAT was Technical

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J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004 45

Use of Ethyl and Propyl (£,Z)-2,4-decadienoates in Codling

Moth Management: Improved Monitoring in Bartlett Pear

with High Dose Lures

A.L. KNIGHT! and D.M. LIGHT’

ABSTRACT

The propyl and ethyl esters of (£,Z)-2,4-decadienoic acid were evaluated in gray halobu-

tyl septa as kairomone lures for both sexes of codling moth, Cydia pomonella (L.). All

studies were conducted in ‘Bartlett’ pear orchards with moderate to high codling moth

adult population densities and treated with sex pheromone dispensers for mating disrup-

tion. Variable results were obtained with kairomone loading experiments. Increasing the

lure loading to 40.0 mg of either the ethyl or propyl ester significantly increased male

and total moth catch in separate experiments. However, in other tests with the ethyl ester

no difference was found in total moth catch in traps baited with 0.1, 1.0, 3.0 or 10.0 mg

versus 40.0 mg lures. The 40.0 mg ethyl and propyl ester lures were both more effective

than a 3.0 mg ethyl ester lure and comparable to a sex pheromone lure in detecting the

beginning of codling moth flight in the spring generation. No difference was found in

moth catch between 40.0 mg propyl and ethyl ester lures. Significantly more females

were caught in traps baited with 1.0 — 10.0 mg than with 1.0 — 100.0 ug lures loaded

with the ethyl ester. In general, kairomone lures caught significantly fewer moths than

sex pheromone lures.

Key Words: Cydia pomonella, monitoring, kairomone, trapping

INTRODUCTION

Codling moth, Cydia pomonella (L.)

(Lepidoptera: Torticidae), 1s a worldwide,

key internal pest of pear, Pyrus communis

L., and adult populations in commercial

orchards are typically monitored with traps

baited with sex pheromone lures (Ried1 ef

al. 1986). Reliable adult monitoring is es-

pecially critical in orchards where codling

moth is managed with applications of its

sex pheromone for mating disruption

(Knight 2002a). The sex pheromone treat-

ment disrupts the attractiveness of the sex

pheromone-baited trap, and traps can fail

to alert pest managers of potential prob-

lems. Efforts to improve the usefulness of

traps in sex pheromone-treated orchards

have included the use of high-dose lures

(Charmillot 1990) and an increased density

of traps (Gut and Brunner 1996).

Identification of ethyl (£,Z)-2,4-

decadienoate as a potent kairomone attrac-

tant for codling moth adults and larvae has

allowed the development of several new

approaches to successfully monitor and

manage this pest (Knight and Light 2001;

Light et al. 2001). Ethyl (£,Z)-2,4-

decadienoate is attractive to both sexes of

codling moth, and traps can be used to

assess the timing of female emergence and

activity, as well as mating status. In addi-

tion, the attractiveness of the lure is not

strongly affected by the application of sex

pheromones (Light et a/. 2001), and the

lure can improve the prediction of local

pest population densities (Knight 2002b).

Ethyl (£,Z)-2,4-decadienoate is a major

volatile of ripe pear (Jennings ef al. 1964),

and is not found in immature fruit or pear-

'Yakima Agricultural Research Laboratory, Agricultural Research Service, USDA 5230 Konnowac Pass

Rd., Wapato, WA 98951

> Western Regional Research Center, Agricultural Research Service, USDA, Albany, CA 94710

46 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

leaf volatiles (Miller et a/. 1989, Scutare-

anu et al. 1997). An initial evaluation sug-

gested that ethyl (£,Z)-2,4-decadienoate

might not be an effective attractant for

codling moth adults in pear orchards (Light

et al. 2001). However, this conclusion was

based on data collected with 1.0 mg lures

placed in three conventional ‘Bartlett’ or-

chards with high levels of codling moth (>

3 moths trapped per day with a sex phero-

mone lure and detectable levels of fruit

injury). The relatively low attractiveness of

the synthetic ethyl (£,Z)-2,4-decadienoate

lure in these pear orchards was hypothe-

sized to be due to olfactory “masking” of

the lure by natural sources of ethyl (£,Z)-

2,4-decadienoate released either from in-

jured or ripening fruits or by competing

host volatiles (Light et a/., 2001). A second

study found that lures loaded with 3.0 mg

of ethyl (£,Z)-2,4-decadienoate were simi-

lar or more attractive than sex pheromone

lures in four cultivars of pear when or-

chards were treated with sex pheromones

(Knight et al. 2005). Ethyl (£,Z)-2,4-

decadienoate lures performed similarly

early and late in the season relative to a sex

pheromone lure in these cultivars suggest-

ing that maturation of fruit was not an im-

portant factor affecting lure attractiveness.

Ethyl (£,Z)-2,4-decadienoate lures again

performed poorly only in ‘Bartlett’ pear

orchards with high population densities of

codling moth that were defined by catches

in sex pheromone-baited traps exceeding

20 moths per season and the presence of

fruit injury (Knight et a/. 2005).

Improvements in developing a more

attractive kairomone lure for codling moth

in pear may involve optimizing its emis-

sion rate and/or the use of alternative at-

tractants. Light et al. (2001) reported that

ethyl (£,Z)-2,4-decadienoate loaded into

gray halobutyl lures was attractive at doses

> 10.0 ug, and the highest moth catches in

walnut orchards occurred with 10.0 mg

lures. Studies testing doses of ethyl (£,Z)-

2,4-decadienoate > 3.0 mg in pear have not

been reported. Among the 23 volatile

blends tested by Light et a/. (2001), only

the blend of methyl and ethyl esters of ten-

carbon acids were attractive to adult cod-

ling moth. Within this group, methyl (£,Z)-

2,4-decadienoate was found to be some-

what attractive in both apple and walnut

orchards. This compound was also attrac-

tive to neonate codling moth (Knight and

Light 2001). Unfortunately, the methyl

ester 1s another component of ripe pears

(Heinz et al. 1966, Shiota 1990), and its

attractiveness to codling moth would also

likely be influenced by competition with

volatile fruit odors within the orchard.

An alternative approach in developing

an improved kairomone may be to utilize a

related volatile that 1s not present in pear

orchards. Propyl (£,Z)-2,4-decadienoate

has been identified from pear by GLC

analysis following an isopentane extraction

of ripe ‘Bartlett? puree (Creveling and

Jennings 1970), but not from volatile head-

space collections of intact fruit (Light et al.

2001) or codling moth-injured fruit (D. M.

L., unpublished data). GC-EAD antennal

response to a synthetic homologous series

of decadienoic esters found that codling

moth’s antennal receptivity is stimulated

by the ethyl ester, with both the methyl-

and propyl-esters eliciting a smaller depo-

larization response (D. M. L., unpublished

data). The behavioral effects elicited in

codling moth by _ propyl (£,Z)-2,4-

decadienoate are unreported. Herein, we

report studies optimizing the dose of ethyl

and propyl (£,Z)-2,4-decadienoate in sepa-

rate lures for monitoring adult codling

moth in ‘Bartlett’ pear.

MATERIALS AND METHODS

Field test protocol. Field trials were

conducted in 1999, 2001, and 2002 to

evaluate the attractiveness of lures loaded

with different doses of ethyl and propyl

(E,Z)-2,4-decadienoate versus sex phero-

mone lures (L2™ and Megalure™, Trécé

Inc., Salinas, California [CA]). The ethyl

(93.7% A.I.) and propyl esters (94.7%

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

A.I.) were synthesized by Trécé Inc. and

loaded in gray halobutyl elastomer septa.

All studies were conducted in ‘Bartlett’

pear orchards located near Wapato, Wash-

ington (WA) and treated with 700 — 1,000

Isomate-C PLUS sex pheromone dispens-

ers (Pacific Biocontrol, Vancouver, WA)

per ha. All studies were conducted with

diamond-shaped sticky traps (Pherocon

IIB, Trécé Inc., Salinas, CA) attached to

poles placed in the upper third of the trees’

canopy. Traps were placed 30 — 50 m apart

within each orchard. Traps were checked

weekly and replaced when needed. Moths

were sexed in all studies.

Optimizing the lure dose of ethyl

(E,Z)-2,4-decadienoate. Two experiments

were conducted in 1999 to examine vari-

ous doses of ethyl ester. Experiment 1

compared the attractiveness of lures loaded

with the ethyl ester at doses of 1.0, 10.0,

and 100.0 ug and 1.0, 3.0, and 10.0 mg

versus the L2™ sex pheromone lure. Eight

replicates of each lure dose were used.

Traps were randomized, placed in the or-

chard on 21 May, and checked weekly

until 28 June. Traps were not rotated in

this study. Experiment 2 evaluated a

smaller subset of lure doses of the ethyl

ester: 1.0, 10.0, and 40.0 mg, versus the

Megalure’™. Nine replicates of each lure

type were randomized in the field on 30

June, and traps were checked and rotated

weekly until 27 July.

Optimizing the lure dose of propyl

(E,Z)-2,4-decadienoate. An experiment

was conducted in 2001 to compare the

attractiveness of the propyl ester at lure

doses of 1.0, 3.0. 10.0 and 40.0 mg versus

the standard 3.0 mg ethyl ester lure. Ten

replicates of each lure dose and type were

randomly placed within a single orchard on

9 May and checked weekly until 5 July.

Traps were rotated within the orchard each

week.

Comparison of kairomone and sex

pheromone lures. Two experiments were

conducted to compare the attractiveness of

lures loaded with 3.0 or 40.0 mg ethyl es-

ter, a lure loaded with 40.0 mg propyl es-

ter, and the commercial high-dose sex

pheromone lure, Megalure’™. The first

experiment was conducted during 2001 in

ten orchards. Traps were placed in each

orchard on 3 July and checked and rotated

each week until 15 August. The second

experiment was conducted in 2002 in the

same ten orchards. Traps were placed in

the orchards on 22 April and checked and

rotated weekly until 1 July.

Data analysis. Significant differences

in the cumulative moth catch in traps

baited with each lure over the specified

time interval were determined with one

way analysis of variance (ANOVA), P <

0.05 (Analytical Software 2000). Count

data were transformed prior to analysis

with square root (x + 0.01). Differences in

the detection of first moth flight among

lures were determined by ANOVA with

data collected in 2002. Means were sepa-

rated with Fisher’s least significant differ-

ence test within all significant ANOVA’s.

RESULTS

Optimizing the lure dose of ethyl

(E,Z)-2,4-decadienoate. Significant differ-

ences were found among the various doses

of the ethyl ester and the sex pheromone

lure in the cumulative catch of male (F =

20.38; df = 6, 49; P < 0.001) and total

moths (F = 16.09; df = 6, 49; P< 0.001) in

experiment 1 (Table 1). The sex phero-

mone lure caught significantly more males

and total moths than any of the ethyl ester

lures. Traps baited with ethyl ester lures

loaded with 1.0, 3.0, and 10.0 mg caught

significantly more males than traps baited

with 1.0 and 10.0 pug lures and more total

moths than traps baited with the 1.0 pug

lure. Significant differences were found in

the catch of female moths among the kai-

romone lures (F' = 7.19; df = 5, 42; P <

0.001) (Table 1). Lures loaded with 1.0 —

10.0 mg ethyl ester caught significantly

more female moths than lures loaded with

1.0, 10.0, and 100.0 ug (Table 1).

48 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

Attractiveness of ethyl (£,Z)-2,4-decadienoate (Et-E,Z-DD) lures compared with sex phero-

mone lures in ‘Bartlett’ pear orchards, 1999.

Mean cumulative capture + SE of codling moth per trap’

Exp.” Lure, loading Males Females* Total

] Et-E£,Z-DD, 1.0 ug 0.50 + 0.38d 0.38 + 0.18b 0.88 + 0.52d

Et-E,Z-DD, 10.0 pg 1.25 0/39¢d 0.75 + 0.31b 2.00 + 0.85cd

Et-E,Z-DD, 100.0 pg 3.13 + 0.88bc 1.00 + 0.50b 4.13 + 0.99bced

Et-E,Z-DD, 1.0 mg 4.50 + 0.93b 3.13+1.0la 7.63 + 1.61be

Et-E,Z-DD, 3.0 mg 5.25 2 10b 3,25 = 0.75a 8.50 + 1.46b

Et-E,Z-DD, 10.0 mg 5.50 + 0.99b 4.75 + 0.90a 10.25+1.71b

Sex pheromone, N.A. ° 28.00 + 5.20a - 28.00 + 5.20a

2 Et-E,Z-DD, 1.0 mg 2.33 + 0.80c 0.89 + 0.54a 3.22 + 10%c

Et-E,Z-DD, 10.0 mg 1.78 + 0.49c 0.89 + 0.35a 2.07 Ol82C

Et-E,Z-DD, 40.0 mg 8.33 + 1.73b 1.00 + 0.47a 9:33 a22-130

Sex Pheromone, N.A. ° 21.78 + 4.98a - 21.78 + 4.98a

‘Column means within each experiment followed by a different letter are significantly differ-

ent at P < 0.05, Fisher’s LSD.

Experiment 1 was conducted from 21 May —22 June and experiment 2 was conducted from 30

June — 27 July 1999.

*Not available. Proprietary loadings in the L2™ and Megalure™ sex pheromone lures used in

experiments | and 2, respectively have not been published (Trécé Inc., Salinas, CA).

Significant differences in the catch of

male (F' = 12.08; df = 3, 32; P < 0.0001)

and total moths (F = 15.37; df = 3, 32; P<

0.0001) among the ethyl ester and sex

pheromone lures were also found in ex-

periment 2 (Table 1). The sex pheromone

lure caught significantly more males and

total moths than any of the three doses of

the ethyl ester tested. The 40.0 mg ethyl

ester lure caught significantly more males

and total moths than the 1.0 and 10.0 mg

lures. No significant differences in the

catch of female moths occurred among

doses of the ethyl ester in this experiment

(F = 0.02; df = 2, 24; P= 0.98).

Optimizing the lure dose of propyl

(E,Z)-2,4-decadienoate. Significant differ-

ences were found in the mean captures of

males (F= 3.91; df = 4, 45; P < 0.01) and

total moths (F' = 3.23; df= 4, 45; P < 0.05)

among different doses of the propyl ester

and the 3.0 mg ethyl ester lure (Table 2).

The highest dose of the propyl ester (40.0

mg) caught significantly more males and

total moths than the other lures. No differ-

ence was found among lures in the catch of

female codling moth (F = 2.29; df = 4, 45;

P =0.07).

Comparison of kairomone and sex

pheromone lures. During the first genera-

tion flight in 2002 there was no difference

in moth catch among the sex pheromone

and kairomone lures (F = 0.97; df = 3, 36;

P =0.42). However, there was a significant

difference among lures in the first detec-

tion of moth flight (F = 4.39; df = 3, 36; P

< 0.01). The first adult codling moth

caught by the 3.0 mg ethyl ester lure was

on average nearly 2 wk later than the other

lures (Table 3). The high-dose kairomone

and sex pheromone lures did not differ in

their detection of the start of codling

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

Table 2.

Evaluation of the attractiveness of ethyl (£,Z)-2,4-decadienoate (Et-E,Z-DD) and propyl (£,Z)-

2,4-decadienoate (Pr-£,Z-DD) lures in ten Bartlett pear orchards from 9 May to 5 July 2001.

Mean cumulative capture + SE of codling moth per trap’

Lure Loading (mg) Males Females Total

Pr-E,Z-DD 1.0 2.3 + 0.6b 0.8 + 0.3a 3.1+0.6b

Pr-E,Z-DD 3.0 2.6 + 0.6b 1.0+0.3a 3.6 +0.8b

Pr-E,Z-DD 10.0 2.4+0.4b 0.2+0.1la 2.6 + 0.4b

Pr-E,Z-DD 40.0 5.4+0.9a 0.6+0.3a 6.0+ 1.0a

Et-£,Z-DD 3.0 3.5 0.70 0.2+0.1la 3.7 + 0.6b

‘Column means followed by a different letter are significantly different at P < 0.05, Fisher’s

LSD.

Table 3.

The effectiveness of the ethyl (£,Z)-2,4-decadienoate (Et-E,Z-DD), propyl (E,Z)-2,4-

decadienoate (Pr-E,Z-DD), and sex pheromone lures in monitoring first generation codling

moth in ten ‘Bartlett’ pear orchards treated with sex pheromone, 22 April to 1 July 2002.

Mean + SE cumulative

Mean + SE weeks to

ate oasis cine) moth catch per trap’ first moth catch

Pr-£,Z-DD 40.0 94+ 1.7a 3,14 0.5a

Et-E,Z-DD 3.0 14.2 + 3.6a 4.8+0.2b

Et-E,Z-DD 40.0 15.4+3.7a 2.2+0.la

Sex pheromone Nak 24.8 + 12.0a 3.0+0.8a

‘Column means followed by a different letter are significantly different at P < 0.05, Fisher’s

LSD.

Not available. Proprietary loading in the Megalure’™ high-dose sex pheromone lure has not

been published (Trécé Inc., Salinas, CA).

moth’s spring flight. A significant differ-

ence in the capture of codling moth adults

was found among lures during the second

generation in 2001 (F = 4.06; df = 3, 36; P

< 0.05). The sex pheromone lure caught 4-

to 13-times more moths than the various

kairomone lures (Table 4). No differences

in male, female, and total moth catch were

found among kairomone lures in this test.

DISCUSSION

The hypothesis and rationale for the

synthesis and testing of the un-natural syn-

thetic propyl ester were the potential for its

greater detectability, attractiveness, or cap-

ture activity in orchards where high levels

of pear fruit damage are causing the preco-

cious liberation of large, perhaps masking,

amounts of the natural methyl and ethyl

esters. However, our results with the pro-

pyl ester lures were inconsistent. The 40.0

mg propyl ester lure caught significantly

more total moths and males than similar

lures loaded with 1.0 — 10.0 mg and more

than the 3.0 mg ethyl lure during May and

50 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 4.

Evaluation of the attractiveness of the ethyl (£,Z)-2,4-decadienoate (Et-E,Z-DD), propyl (E, Z)-

2,4-decadienoate (Pr-E,Z-DD), and a commercial sex pheromone lure in monitoring second

generation codling moth flight in ten ‘Bartlett’ pear orchards treated with sex pheromone, 3

July to 15 August 2001.

Mean + SE cumulative moth catch per trap!

Lure Dose (mg) Males Females Total

Pr-E,Z-DD 40.0 36.2196 3.0 4 19a 7.0 + 4.5b

Et-£,Z-DD 3.0 3.0 + 1.0b del aeel 8a 6.1 +2.7b

Et-E,Z-DD 40.0 2.0+0.5b 1.4+0.6a 3.4+0.9b

Sex pheromone N.A? 26.9 + 9.3a ‘ 26.9 + 9.3a

‘Column means followed by a different letter are significantly different at P < 0.05, Fisher’s

LSD.

Not available. Proprietary loading in the Megalure ™ high-dose sex pheromone lure has not

been published (Trécé Inc., Salinas, CA).

June in 2001, yet from July to mid August

in 2001 and from late April through June

in 2002 traps baited with the 40.0 mg pro-

py! lure did not catch more moths than the

3.0 mg ethyl ester lure. Thus no clear ad-

vantage in using the propyl ester versus the

ethyl ester was demonstrated in these stud-

les.

The effect of increasing the loading rate

of the ethyl ester was also inconsistent

among experiments. No significant differ-

ence in moth catch was found in traps

baited with 1.0 — 10.0 mg ethyl ester in late

May to June in 1999, but the 40.0 mg lure

caught significantly more total moths and

males than either the 1.0 or 10.0 mg lure

during July. However, from July to mid

August in 2001 and from late April

through June in 2002 no difference in moth

catch occurred in traps baited with either a

3.0 or 40.0 mg ethyl ester lure.

The 40.0 mg kairomone lures, however,

were effective in detecting the beginning

of the first generation moth flight in pear,

whereas moth catch in traps baited with the

3.0 mg ethyl ester lure was delayed. Simi-

lar patterns of delayed first moth catch

have been found with 3.0 mg ethyl ester

lures in apple orchards (A.L.K., unpub-

lished data), but not in walnut (Light et al.

2001). Accurate detection of the start of

moth flight (“Biofix”) is widely used to

predict the start of egg hatch and in timing

insecticide applications (Riedl et a/. 1976).

Thus, the 40.0 mg ethyl ester lure may be

an improved kairomone lure to monitor

early-season codling moth flight activity.

Traps baited with either kairomone

were not as effective as traps baited with

sex pheromone in capturing codling moth

in all but one study (early season 2002

trial). This negative result was similar to

other data collected with the 3.0 mg ethyl

ester lure from ‘Bartlett’? orchards in the

same fruit-growing region of WA (Knight

et al. 2005). The relatively poor perform-

ance of the ethyl ester lure in both WA

studies is in contrast to its higher perform-

ance than sex pheromone lures in CA

‘Bartlett’? orchards (Zoller and Zoller

2003). A major difference between the

published WA and CA studies is the popu-

lation densities of codling moth within the

monitored orchards. Mean moth catch in

sex pheromone-baited traps was >80 moths

per trap per season in WA ‘Bartlett’ or-

chards (Knight et a/. 2005) and >20 moths

per trap over the one- to two-month studies

reported here. Codling moth fruit injury

occurred at levels >10.0% in many of these

orchards. In comparison, mean cumulative

moth catch in the sex pheromone-baited

traps was 2.7 per season in CA ‘Bartlett’

orchards and fruit imjury was <0.5%

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

(Zoller and Zoller 2003). A similar reduc-

tion in the attractiveness of the ethyl ester

was found in the second generation of cod-

ling moth for apple orchards with high

levels of fruit injury (Light et al. 2001).

Additional studies are needed to refine

under which field conditions the pear es-

ters are likely to perform well, 1.e. crop,

cultivar, season, crop load, fruit maturity,

and percent injured fruit (Knight 2002b).

Comparing the statistical correlations of

moth catch in sex pheromone- and kairo-

mone-baited traps with egg density or lev-

els of fruit injury versus the absolute

counts would likely be more informative in

developing an improved monitoring pro-

gram for codling moth.

Similarly, interpretation of the numbers

and timing of female moth capture is a

unique feature of kairomone-baited traps

that has not been fully utilized. Traps

baited with ethyl ester typically catch from

40 — 60% female codling moth (Light ef al.

2001), and similar data were reported

across four pear cultivars in orchards with

both low and high moth population densi-

ties (Knight ef a/. 2005). In our current

study, female moths were caught in traps

baited with either ester and across all lure-

loading rates. Significantly more female

moths were caught in traps baited with

>1.0 mg ethyl ester than at the lower rates

tested and no additional increase was

found with lure loadings up to 40.0 mg.

Results with the propyl ester were similar

and no differences in female catch were

noted between 40.0 mg ethyl and propyl

lures. Establishing moth catch thresholds

based on female codling moth density

could be a useful approach to improve

management of this pest, especially in sex

pheromone-treated orchards (Knight

2002b). In addition, initiating predictive

timing models of egg hatch based on a

“Biofix” of first female moth catch could

improve current models. Incorporating

these kairomone-baited traps in the inte-

grated management of codling moth will

require additional testing and refinement.

ACKNOWLEDGEMENTS

We would like to thank Brad

Christianson and Duane Larson (U.S.D.A.,

Agricultural Research Service, Wapato,

WA) for their help in setting up plots and

collecting data. We appreciate the synthe-

sis of the propyl isomer and the supply of

septa for both ester isomers provided by

Trécé Inc., Salinas, CA. Helpful comments

were provided on an earlier draft by Tom

Unruh, U.S.D.A., Wapato, WA; Harvey

Reissig, Cornell University, Geneva, NY;

Richard Hilton, Oregon State University,

Medford, OR; Jim Hanson, U.S.D.A., Wa-

pato, WA; John Hardman, Agricultural

Canada, Kentville, Nova Scotia; Henry

Hogmire, West Virginia University, Kear-

neysville, WV; and Chris Maier, Connecti-

cut Agricultural Experiment Station, New

Haven, CT. This work was partially sup-

ported by the Washington Tree Fruit Re-

search Commission, Wenatchee, WA.

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Charmillot, P.J. 1990. Mating disruption technique to control codling moth in WesternSwitzerland, pp.

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for insect pest management. Marcel Dekker, New York.

Creveling, R.K. and W.G. Jennings. 1970. Volatile components of Bartlett pear. Journal of Agriculture

and Food Chemistry 18: 19-24.

Gut, L.J. and J.F. Brunner. 1996. Implementing codling moth mating disruption in Washington pome fruit

orchards. Tree Fruit Research Extension Center Information Series, No. 1. Washington State Univer-

sity. Wenatchee, WA.

Heinz, D.E., M.R. Sevenants, and W.G. Jennings. 1966. Preparation of fruit essences for gas chromatogra-

phy. Journal of Food Science 31: 63-68.

Jennings, W.G., R.K. Creveling, and D.E. Heinz. 1964. Volatile esters of Bartlett pear. IV. Esters of

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trans:2-cis:4-decadienoic acid. Journal of Food Science 29: 730-734.

Knight, A.L. 2002a. A comparison of gray halo-butyl elastomer and red rubber septa to monitor codling

moth (Lepidoptera: Tortricidae) in sex pheromone-treated orchards. Journal of the Entomological

Society of British Columbia 99: 123-132.

Knight, A.L. 2002b. Using the kairomone lure, DA2313 to monitor codling moth in apple and pear, p. 27.

In Proceedings, Western Orchard Pest and Disease Management Conference, 9-11 January 2002.

Portland , OR.

Knight, A.L. and D.M. Light. 2001. Attractants from ‘Bartlett’ pear for codling moth, Cydia pomonella

(L.), larvae. Naturwissenschaften 88:339-342.

Knight, A.L., R.P.J. Potting and D.M. Light. 2002. Modeling the impact of a sex pheromone/kairomone

attracticide for management of codling moth (Cydia pomonella). Acta Hort 584: 215-220.

Knight, A.L., P. VanBuskirk, R. Hilton, B Zoller, and D.M. Light. 2005. Monitoring codling moth

(Lepidoptera: Tortricidae) in four cultivars of pear. Acta Hort. (in press).

Light, D.M., A.L. Knight, C.A. Henrick, D. Rajapaska, B. Lingren, J.C. Dickens, K.M.Reynolds, R.G.

Buttery, G. Merrill, J. Roitman and B.C. Campbell. 2001. A pear-derived kairomone with pheromonal

potency that attracts male and female codling moth, Cydia pomonella (L.). Naturwissenschaften

88:333-338.

Miller, R.L., D.D. Bills, and R.G. Buttery. 1989. Volatile components from Bartlett and Bradford pear

leaves. Journal of Agriculture and Food Chemistry 37: 1476-1479.

Riedl, H., B.A. Croft, and A.J. Howitt. 1976. Forecasting codling moth phenology based on pheromone

trap catches and physiological-time models. The Canadian Entomologist 108: 449-460.

Riedl, H., J.F. Howell, P.S. McNally, and P.H. Westigard. 1986. Codling moth management, use and

standardization of pheromone trapping systems. University of California Bulletin 1918. Berkeley, CA.

Scutareanu, P., B. Drukker, J. Bruin, M.A. Posthumus, and M.W. Sabelis. 1997. Volatiles from Psylla-

infested pear trees and their possible involvement in attraction of Anthocorid predators. Journal of

Chemical Ecology 23: 2241-2260.

Shiota, H. 1990. Changes in the volatile composition of La France pear during maturation. Journal of

Science and Food Agriculture 52: 421-429

Zoller, B.G. and A.M. Zoller. 2003. Comparison of kairomone DA 2313 and pheromone lure trapping for

codling moth with oviposition monitoring, p. 22. Jn Proceedings, Western Orchard Pest and Disease

Management Conference, 15-17 January 2003, Portland, OR.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004 53

Use of Ethyl] (£,Z)-2,4-decadienoate in Codling Moth

Management: Stimulation of Oviposition

A.L. KNIGHT! and D.M. LIGHT?

ABSTRACT

The effect of the pear volatile, ethyl (£,Z)-2,4-decadienoate (Et-£,Z-DD), on oviposition

by codling moth, Cydia pomonella (L.), was evaluated in a series of choice and no-

choice laboratory experiments and in subsequent field tests conducted in apple and wal-

nut. Gray halobutyl elastomer septa loaded with 1.0 and 100.0 wg Et-E,Z-DD signifi-

cantly increased the numbers of eggs laid by a laboratory population in 96 h no-choice

assays by 2-fold. In addition, the number of eggs laid near the Et-E£,Z-DD versus a sol-

vent blank dispenser was significantly higher in choice bioassays across a similar range

of septa loadings. Oviposition rates by a field-collected post-diapause strain of codling

moth were significantly increased by the addition of a 1.0-ug septa versus a solvent

blank dispenser in a no-choice bioassay. Field trials were conducted in apple and walnut

to develop an artificial egg trap baited with Et-E,Z-DD to monitor codling moth oviposi-

tion. Septa loaded with 0.1 to 10.0 mg did not significantly increase oviposition versus

solvent blank dispensers on a Mylar plastic collar trap or on the adjacent leaves and fruit

in apple. Significantly more eggs were laid on the fruit and foliage than on the plastic

collar. No eggs were deposited on non-bearing apple shoots baited with 0.1 — 40.0 mg

Et-E,Z-DD septa. Similarly, no eggs were deposited on cylindrical wax paper-covered

plastic traps baited with 10.0 pg to 1.0 mg Et-E£,Z-DD septa in walnut orchards. The

potential of Et-E,Z-DD to monitor codling moth’s oviposition in the field, stimulate

oviposition by field-collected strains under laboratory conditions, and to improve pest

control by disrupting host location are discussed.

Key Words: Cydia pomonella, oviposition, kairomone, phenology, egg trap

INTRODUCTION

Codling moth, Cydia pomonella (L.)

(Lepidoptera: Tortricidae) is_ typically

monitored in fruit and nut orchards with

sex pheromone-baited traps. The numbers

and timing of male moths captured in these

traps is used to infer the density of female

moths and timing of oviposition (Ried] and

Croft 1974, Riedl et al. 1976). The devel-

opment of an effective, inexpensive tool to

directly monitor the density of codling

moth females and/or oviposition could

improve its management. The sesquiter-

pene, (£,£)-a-farnesene (£,E£-aF), a major

constituent of apple fruit and leaf odors,

was identified as a key adult and larval

attractant for codling moth (Sutherland ef

al. 1974) and was shown to stimulate ovi-

position 1n both choice and no-choice labo-

ratory bioassays (Wearing and Hutchins

1973). Unfortunately, E,E-aF is unstable

in the presence of oxygen and has a very

short residual activity (Anet 1969). Field

trials evaluating the stimulatory effect of

E,E-aF on codling moth oviposition have

not been reported.

Direct monitoring of codling moth egg

density in orchards through foliage and

fruit sampling is labor intensive and often

ineffective due to the relatively low popu-

lation density of this pest in commercial

orchards (Elkins 2002). A novel approach

to monitor codling moth egg density in

'Yakima Agricultural Research Laboratory, Agricultural Research Service, USDA, 5230 Konnowac Pass

Rd., Wapato, WA 98951

* Western Regional Research Center, Agricultural Research Service, USDA, Albany, CA 94710

54 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

California pear orchards has recently been

reported that uses the artificially cutting or

damaging of fruit (Zoller and Zoller 2001).

Pear clusters containing one cut-fruit (2.0-

3.0 cm wedge cut 0.5-1.0 cm deep) were

95-times more likely to contain a codling

moth egg than normal fruit clusters. Yet, a

number of factors increase the variability

of this approach including cultivar and

days before harvest, i.e., Bosc pear clusters

were more attractive than Bartlett; and the

attractiveness of cut- versus uncut-fruit

was only significantly different during the

month before harvest (Zoller 2001). Unfor-

tunately, the incidence of eggs among the

cut-fruit cluster samples in commercial

pear orchards was low (< 1.0%), and the

utility of this labor-intensive approach for

improving the management of codling

moth is unclear (Zoller and Zoller 2001).

Light et al. (2001) and Knight and

Light (2001) found that ethyl (£,Z)-2,4-

decadienoate (Et-£,Z-DD), a_ principal

odorant from ripe pear (Jennings ef al.

1964), was a potent adult and larval kairo-

monal attractant for codling moth. Et-F,Z-

DD appears to be chemically more stable

than E,E-oF and can be loaded in septa to

provide long-lasting, effective monitoring

of adult populations (Light ef al. 2001;

Knight et al. 2005). The potential effects

of Et-E,Z-DD on oviposition of codling

moth have not been reported. Herein, we

report on the effects of Et-E,Z-DD on cod-

ling moth oviposition under laboratory

conditions and evaluate its use as a lure to

monitor egg laying in apple and walnut

orchards.

MATERIALS AND METHODS

Choice and no-choice laboratory ex-

periments. Moths 24-48 hr old were ob-

tained from a laboratory colony reared on

artificial diet (Toba and Howell 1991) at

the U.S.D.A. Yakima Agricultural Re-

search Laboratory in Wapato, WA. Indi-

vidual virgin female moths were paired

with two male moths for 24 h at 25 °C, >

40% R.H., and a 16:8 L:D photoperiod.

Females were then placed in screened (3 x

3 mm) cylindrical cages (11 cm long and 9

cm diameter). Both ends of each cage

were capped with a plastic cover lined with

wax paper. Gray halobutyl elastomer septa

(No. 1888, size No. 1,West Co., Phoenix-

ville. PA) were pinned to the wax paper at

each end of the cage. A 10.0% honey water

wick was inserted into the middle of each

cage.

Choice and no-choice tests were con-

ducted with septa loaded with 1.0 and

100.0 pg Et-£,Z-DD (93.7% A.L, Trécé

Inc., Adair, OK) versus septa treated only

with the solvent, dichloromethane as a

blank. In choice tests an Et-E,Z-DD-loaded

septa and a solvent blank septa were

pinned to the wax paper at opposite ends of

the cage. Identical lures were pinned at

each end of the cage in the no-choice tests.

Tests were run for 96 h inside greenhouses

maintained between 20 — 25 °C. Cages

were spaced > 5 m apart and no more than

four replicates were run on each of six

dates. An additional no-choice test was

conducted with 1.0 ug Et-£,Z-DD septa

versus a solvent control septa using moths

reared from an overwintering population

collected as larvae the previous season in

corrugated bands attached to apple trees.

Larvae had been maintained under dia-

pause conditions (2 °C and total darkness)

for five months and were allowed to

emerge in rooms maintained at 25 °C, 16:8

L:D and > 45% R.H. The numbers of eggs

laid on each wax paper cap were counted

in all experiments and females were dis-

sected to determine their mating status.

Only data from mated females were in-

cluded in the statistical analyses (15 — 20

replicates per comparison).

Development of an egg trap. Studies

were conducted in a greenhouse to develop

a suitable substrate for an artificial egg

trap. The suitability of waxed cardboard

and Mylar plastic as sites of codling moth

Oviposition were compared with natural

apple leaves. Three mated females (< 72 h

old) were placed inside of screened cages

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

with a 1.2 m potted apple seedling. Artifi-

cial substrates were cut to mimic a typical

leaf shape (19.8 cm’) and were clipped to

the main stem of the plant. In the first test

we compared oviposition on the plastic

versus the waxed cardboard substrate. The

height of each type of artificial leaf was

alternated on the seedling at 0.7 and 1.0 m,

and six replicate cages were evaluated

from 14 — 19 March 2001. In a second

test, we compared oviposition on a se-

lected apple leaf on the seedling versus a

similar-sized plastic leaf. Both the natural

and artificial leaves were positioned on the

seedling at a height of 1.0 m and on oppo-

site sides of the shoot. Twenty-four cage

replicates of this test were conducted be-

tween 23 March and 26 April 2001. The

number of eggs on each artificial and natu-

ral apple leaf was counted after 5 d.

Field evaluation of egg traps in apple.

Studies were conducted in an unsprayed

‘Red Delicious’ apple orchard situated

near Parker Heights, WA from 18 — 29

May 2001. Square plastic sheets (0.1 m’)

were slit and folded as collars around fruit

and foliage clusters and baited with either

0.1, 1.0, or 10.0 mg Et-£,Z-DD lures or an

unbaited solvent-only lure (nine replicates

per treatment). Baited trees were spaced >

20 m apart and traps were placed in the

upper third of the canopy. Fruit monitor-

ing indicated that no fruit injury was pre-

sent in the orchard when the experiment

was Started. Fruit and leaf clusters were

removed after 7 d and plastic collars, fruits

and leaves were then examined in the labo-

ratory for codling moth eggs and injury. A

second test was conducted from 5 —- 11

June 2001 in another unsprayed ‘Red Dell-

cious’ apple orchard situated near Moxee,

WA using the plastic collar trap baited

with either 3.0 mg Et-£,Z-DD or solvent-

only lures. Twenty replicates of each lure

type were placed on shoots with and with-

out fruit. Only uninjured fruit clusters were

used in this study. Collars, foliage, and

fruit were examined for eggs after 6 d.

Eggs in both studies were categorized into

developmental stages based on their mor-

phology (Richardson et al. 1982). Only

‘white’ eggs and ‘red ring’ eggs character-

ized as having only one visible stemmata

(< stage 11) were scored as having been

laid during each test.

A third apple trial was conducted dur-

ing 2002 in the Moxee apple orchard to

examine if oviposition could be stimulated

to occur on non-bearing shoots baited with

Et-E,Z-DD lures. Septa loaded with either

1.0, 3.0, 10.0, 20.0, or 40.0 mg Et-E,Z-DD

and solvent-only septa (10 replicates per

treatment) were pinned to non-bearing

shoots on 15 June. One septum was at-

tached per tree and baited-trees were

spaced 5 — 6 m apart. Five replicates of

each lure loading were collected after 10 d

and the rest were collected after 20 d. All

shoots were examined for hatched and

unhatched eggs. Two Et-£,Z-DD-baited

sticky delta-shaped traps (Trécé Inc.,

Adair, OK) were used to monitor the activ-

ity of female codling moths in this orchard

during this test. In addition, 30 randomly

selected fruit from 20 trees situated within

100 m of the center of the study site were

inspected for codling moth injury at the

end of this test to assess pest pressure.

Field evaluation of egg traps in wal-

nut. Studies were conducted from mid-

June through September 2002 in a

‘Chandler’ walnut orchard (Dixon, CA)

characterized as having a moderate codling

moth population density based on early-

season moth catches in sex pheromone-

baited traps. An oviposition trap was con-

structed using a plastic sheet (21.0 x 28.0

cm) covered with wax paper on both sides.

The plastic sheet was rolled into a 9 cm

diameter tube, then secured and hung hori-

zontally by a wire trap hanger. Septa im-

pregnated with either 10.0, 100.0, or

1,000.0 ug Et-E,Z-DD or solvent-only

were attached by a plastic septa holder

from the center of the inner tube of the

trap. Traps were hung in the upper third

of the 8.0 m canopy and baited trees were

separated by 80 m. Three replicate blocks

were established within three orchards (9

replicates of each lure rate). Traps were

checked weekly for eggs and septa were

replaced every two weeks. In July, a 500-

56 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

nut sample was collected from the canopy

in each replicate block and examined for

codling moth injury.

Statistical analysis. The total number

of eggs laid in cages baited either with Et-

E,Z-DD or solvent-only septa in choice

and non-choice tests were compared with

paired and unpaired t tests, respectively, at

a P< 0.05 level of significance (Analytical

Software 2000). A paired t-test was used to

compare the suitability of substrates for

Oviposition in the greenhouse studies.

Analysis of variance (ANOVA) was used

to evaluate the influence of lure loading

rate on oviposition on Mylar traps and as-

sociated fruit and foliage in apple and to

compare oviposition on the Mylar collar

versus fruit and foliage. Mean separation

following a significant ANOVA was deter-

mined with a LSD test, P < 0.05.

RESULTS

Choice and no-choice laboratory ex-

periments. Septa loaded with Et-£,Z-DD

significantly increased oviposition by a

laboratory strain of codling moth in green-

house tests in both choice and no-choice

tests with lures baited with 1.0 and 100.0

ug Et-E,Z-DD versus solvent-only lures

(Table 1). The mean number of eggs laid

on wax paper next to the kairomone lure

was 2-5 fold higher than next to a blank

lure in choice-tests. In addition, approxi-

mately 2-fold more eggs were laid in cages

baited with Et-E,Z-DD lures versus with

solvent-only lures in no-choice tests.

Field-collected codling moth females laid

twice the number of eggs in cages baited

with Et-£,Z-DD than in cages baited with

the solvent control (Table 1).

Development of an egg trap. No dif-

ference was found in the number of eggs

laid on the waxed cardboard leaf-model

(mean + SE = 9.7 + 2.5) versus the plastic

leaf-model (mean + SE = 8.3 + 2.3) (t =

0.39, df = 10, P= 0.71). The Mylar plastic

leaf-model was chosen for subsequent field

tests due to its greater stability when ex-

posed to adverse field conditions, 1.e. pre-

cipitation. However, significantly more

eggs were deposited on the apple leaf

(mean + SE = 9.6 + 2.4) versus the plastic

leaf-models (mean + SE = 4.3 + 1.2) (t=-

3.73, df = 46, P< 0.001).

Field evaluation of egg traps in apple.

The mean + SE number of fruit within the

Mylar collar trap in the May 2001 test was

2.9 + 0.3 and there was no significant dif-

ference in fruit density among lure treat-

ments, F = 0.35; df = 3, 32; P= 0.79. The

mean + SE number of eggs that had al-

ready been deposited (> stage 11 plus

hatched eggs) on the fruit and foliage sur-

rounded by the Mylar collar was 1.3 + 0.3

per cluster. There was no significant differ-

ence in the mean density of already depos-

ited eggs among lure treatments in this test,

F = 0.93; df = 3, 32; P = 0.44. Few new

eggs (< stage 11) were laid on either the

Mylar trap or the associated foliage and

fruit during the May 2001 field experiment

(Table 2). Total egg density on the Mylar,

foliage, and fruit did not differ among lure

types, F = 0.87; df = 3, 32, P = 0.47. Sig-

nificantly more eggs were laid on the foli-

age and fruit than on the Mylar plastic col-

lar across all lure loadings and the solvent

blank, F = 5.69; df = 1, 70; P< 0.05. An

average of 23% of the fruit within the My-

lar collars were injured at the end of the

experiment.

No eggs were deposited on Mylar col-

lars or foliage in non-bearing shoots baited

with either the 3.0 mg Et-£,Z-DD or a

blank lure in the June 2001 test. Similarly,

no eggs were deposited on the Mylar col-

lars surrounding fruit. The mean + SE

number of fruit within the Mylar collar

trap was 2.4 + 0.1 and there was no signifi-

cant difference in fruit density between

lure treatments on fruit-bearing shoots, F =

0.29; df = 1, 38; P = 0.59. The mean + SE

number of eggs that had already been de-

posited (> stage 11 plus hatched eggs) on

the fruit and foliage surrounded by the

Mylar collar was 1.2 + 0.3 per cluster.

There was no significant difference in the

mean density of already deposited eggs

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

The effects of ethyl (£,Z)-2,4-decadienoate loaded in gray halobutyl elastomer septa on egg

laying of mated codling moth in choice and non-choice laboratory tests conducted for 96 h.

Test Type Treatment No. replicates

Choice 100.0 pg 18

Blank

Choice 1.0 pg 20

Blank

No-choice 100.0 pg 20

Blank

No-choice 1.0 pg 20

Blank

No-choice’ 1.0 pg 15

Blank

Mean + SE no. eggs Statistical test '

laid per cage P-value

210 te3.7 = 0,05

11.6+3.4

25-0252 < 0.001

44+1.4

31.0+3.4 < 0.001

14.2+2.8

21. < 0.05

1232 3:0

13.1+3.8 < 0.05

Ded eae

' A paired and unpaired t-test were used to analyze data from the choice and no-choice tests,

respectively.

* Field collected adults reared from pupae collected in corrugated bands placed in an unsprayed

apple orchard.

Table 2.

Density of codling moth eggs deposited on Mylar traps and associated fruit and leaf clusters

baited with ethyl (£,Z)-2,4-decadienoate or a solvent-only lure in an apple orchard during May

(nine replicates per lure) and June (20 replicates per lure) 2001.

Mean + SE no. eggs laid on

Lure load (mg) Mylar collar Foliage and fruit Both

May 2001

Solvent only 010-011 0.22 + 0.15 0.33 + 0.17

0.1 0.00 + 0.00 0.33 + 0.17 0.33 +0.17

1.0 0.00 + 0.00 L.11+0.59 LIT 0.59

10.0 0.22 + 0.15 0.44 + 0.34 0.67 + 0.47

June 2001

Solvent only 0.00 + 0.00 0.10+0.10 0.10+0.10

3.0 0.00 + 0.00 0.35 + 0.17 0.35+0.17

between lure treatments on fruit-bearing

shoots in this test, F = 1.18; df= 1, 38; P=

0.28. The number of eggs laid on foliage

and fruit in collars baited with a 3.0 mg

versus the solvent-only lure was not sig-

nificant (F = 1.66; df = 1, 38; P = 0.21).

An average of 11% of the fruit within My-

lar collars were injured at the end of the

experiment.

No eggs were deposited on non-bearing

apple shoots baited with Et-E,Z-DD or the

solvent control lures during the 2002

study. The mean + SE capture of female

codling moth in sticky traps baited with a

Et-E,Z-DD lure was 0.3 + 0.1 moths per

night. Fruit injury by codling moth on a

sample of trees within 100 m of the study

site averaged 18.7% in mid July.

Field evaluation of egg traps in wal-

nut. No eggs were laid on the wax paper-

covered plastic tube traps placed in walnut

orchards during the 14 wk study. How-

58 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

ever, the population of codling moth in this

orchard was moderate to high. Nut damage

in July averaged 3.0% in canopy samples.

In addition, traps baited with both sex

pheromone and Et-£,Z-DD lures caught a

large number of moths, 3 — 6 moths per

trap per night during the test. Codling moth

adults were observed on several occasions

resting on the plastic egg traps.

DISCUSSION

Our studies to develop an effective

monitoring trap for codling moth oviposi-

tion with Et-£,Z-DD in apple and walnut

were largely unsuccessful. Mylar and

waxed paper were poor artificial substrates

for oviposition by codling moth compared

with fruit and foliage. Despite working in

orchards with relatively very high popula-

tion densities of codling moth (levels of

fruit and nut injury > 3.0%), rates of ovi-

position on fruit and leaves were low, and

the addition of a Et-£,Z-DD lure did not

significantly increase the number of eggs

deposited. Baiting non-bearing shoots with

Et-E,Z-DD lures did not stimulate oviposi-

tion.

Several factors likely contribute to the

difficulty in developing an effective egg

trap for codling moth. The density of cod-

ling moth eggs in most commercial or-

chards is very low and a large number of

traps may be necessary to detect oviposi-

tion (Zoller and Zoller 2001). Females

typically deposit eggs near or on fruit clus-

ters that emit E,E-aF and other volatiles

that stimulate oviposition (Sutherland ef al.

1974). It is unclear whether adding a Et-

E,Z-DD lure could further increase this

stimulation. For example, the addition of

Et-E£,Z-DD to an attractive blend of E,E-aF

and (£)-6-farnesene did enhance male up-

wind flight but not ‘landing at source’ in

flight tunnel studies (Coracini et al. 2004).

Studies addressing the influence of these

volatile blends on short-range female ori-

entation and oviposition have not been

conducted. The cut-pear method is the only

study that has stimulated codling moth

oviposition in the field with the addition of

kairomones (Zoller 2001), but the blend of

volatiles and their emission rates from arti-

ficially injured pears has not been charac-

terized. While a wide range of Et-E,Z-DD

lure loadings was evaluated in our studies

we have not compared the emission rate of

Et-E,Z-DD from cut pears versus these

synthetic lures. Very low Et-E,Z-DD lure

loadings (1.0 — 100.0 ug) stimulated ovi-

position under laboratory conditions. How-

ever, higher rates of Et-E,Z-DD (> 1.0 mg)

are needed to attract adequate numbers of

female moths to traps under field condi-

tions (Light et al. 2001). The successful

development of an egg trap for codling

moth must consider the trade-off between

increasing the number of eggs laid on or

near the trap (short-range stimulation) ver-

sus increasing the likelihood of detecting a

single egg near or on the trap (long-range

attraction). The complexity of visual and

olfactory cues that may stimulate short-

range host location behaviors in codling

moth is not well understood.

Additional factors associated with de-

veloping a practical egg-monitoring pro-

gram for codling moth should be consid-

ered. Lombarkia and Derridj (2002) found

that several primary water-soluble metabo-

lites (sugar alcohols and sugars) isolated

from apple leaves and fruits stimulated

Oviposition by codling moth. Whether the

suitability of a plastic surface might be

improved or the leaf and fruit surfaces en-

hanced by the addition of these or other

chemicals should be investigated. Micro-

encapsulated formulations of Et-£,Z-DD

alone and in blends with other attractive

volatiles could be applied to fruit clusters

to create attractive point sources. Other

physical aspects of the trap could be im-

proved to increase oviposition, such as

providing grooves or folds in the trap’s

surface and the influence of trap color

(Knight and Miliczky 2003).

The attraction of codling moth adults

and neonates plus the stimulation of ovi-

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

position by Et-£,Z-DD could be utilized to

improve management of this pest (Light er

al. 2001; Knight and Light 2001). Labora-

tory studies with Et-E,Z-DD have exam-

ined the use of a paste formulation laced

with insecticides applied as coarse droplets

to control larvae (A. L. K., unpublished

data). The use of attractive kill stations for

females has been evaluated in field trials

and offers promise (Knight et a/. 2002).

Hughes et al. (2003) evaluated the use of

apple odor and £,F-aF to disrupt host

location of neonates and mated females in

laboratory trials. They suggest that natural

mortality of neonates could be increased

with a competitive kairomone-based ap-

proach. A similar design using Et-£,Z-DD

could be effective and should be further

evaluated.

Another potential use of Et-£,Z-DD

can be to increase oviposition by post-

diapause field-collected strains of codling

moth. The overwintering generation of

field-collected populations of codling moth

typically has a much lower fecundity and

mating success under laboratory conditions

than either laboratory-adapted or summer

generation field-collected strains (Howell

1991). Increasing egg production of cod-

ling moth under laboratory conditions has

been facilitated by the addition of ripe ap-

ple fruits, water, or molasses baits (Van

Leeuwen 1947; Wearing ef al. 1973). The

use of a dry, long-lasting Et-£,Z-DD lure

to increase egg laying would facilitate in-

secticide-susceptibility testing of field

populations and in establishing laboratory

colonies (Knight ef a/. 2001).

ACKNOWLEDGEMENTS

We would like to thank Duane Larsen

and Brad Christianson (U.S.D.A., A.R.S.,

Wapato, WA) for their assistance in setting

up these experiments. Helpful comments

were provided by Dave Horton (U.S.D.A.,

A.R.S., Wapato, WA) and several anony-

mous reviewers. This research was par-

tially funded by the Washington Tree Fruit

Research Commission (Wenatchee, WA)

and the Walnut Marketing Board

(Sacramento, CA).

REFERENCES

Analytical Software. 2000. Statistix7, Tallahassee, FI.

Anet, E.F. 1969. Autoxidation of a—farnesene. Australian Journal of Chemistry 22: 2403-2410.

Coracini, M., M. Bengtsson, I. Liblikas, and P. Witzgall. 2004. Attraction of codling moth males to apple

volatiles. Entomologia Experimentalis et Applicata 110: 1-10.

Elkins, R. 2002. Areawide implementation of mating disruption in pears using puffers. Pest Management

Grant Final Report No. 00-0198S. California Department of Pesticide Regulation, Sacramento, CA.

Howell, J.F. 1991. Reproductive biology, pp. 157-174. Jn L.P.S. van der Geest and H.H. Evenhuis (eds.),

Tortricid pests: their biology, natural enemies and control. Elsevier, Amsterdam, The Netherlands.

Hughes, W.O.H., D. Gailey, and J.J. Knapp. 2003. Host location by adult and larval codling moth and the

potential for its disruption by the application of kairomones. Entomologia Experimentalis et Applicata

106: 147-153.

Jennings W.G., R.K. Creveling, and D.E. Heinz. 1964. Volatile esters of Bartlett pear. IV. Esters of

trans:2-cis:4-decadienoic acid. Journal of Food Science 29: 730-734.

Knight, A.L. and D.L. Light. 2001. Attractants from Bartlett pear for codling moth, Cydia pomonella (L.)

larvae. Naturwissenschaften 88: 339-342.

Knight, A.L., J.E. Dunley, and R.K. Jansson. 2001. Baseline monitoring of codling moth (Lepidoptera:

Tortricidae) larval response to benzoylhydrazine insecticides. Journal of Economic Entomology 94:

264-270.

Knight, A.L., R.P.J. Potting, and D.M. Light. 2002. Modeling the impact of a sex pheromone/kairomone

attracticide for management of codling moth (Cydia pomonella). Acta Horticulturae 584: 215-220.

Knight, A.L. and E. Miliczky. 2003. Influence of trap colour on the capture of codling moth (Lepidoptera:

Tortricidae), honeybees, and non-target flies. Journal of the Entomological Society British Columbia

100: 65-70.

Knight, A.L., P. VanBuskirk, R.J. Hilton, B.G. Zoller, and D.M. Light. 2005. Monitoring codling moth in

60 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

four pear cultivars with the pear ester. Acta Horticulturae (in press).

Light, D.M., A.L. Knight, R.G. Buttery, C.A. Henrick, D. Rajapaska, K.M. Reynolds, G. Merrill, J. Roit-

man, J.C. Dickens, W. Lingren, and B.C. Campbell. 2001. Ethyl (2E, 4Z)-2,4-decadienoate: a pear-

derived kairomone with pheromonal potency attracts both sexes of codling moth, Cydia pomonella L.

Naturwissenschaften 88: 333-338.

Lombarkia, N. and S. Derridj. 2002. Incidence of apple fruit and leaf surface metabolites on Cydia pomo-

nella oviposition. Entomologia Experimentalis et Applicata 104: 79-87.

Richardson, J.C., C.D. Jorgensen, and B.A. Croft. 1982. Embryogenesis of the codling moth, Laspeyresia

pomonella: use in validating phenology models. Annals Entomological Society of America 75: 201-

209.

Riedl, H. and B.A. Croft. 1974. A study of pheromone trap catches in relation to codling moth damage.

The Canadian Entomologist 106: 525-537.

Riedl, H., B.A. Croft, and A.J. Howitt. 1976. Forecasting codling moth phenology based on pheromone

trap catches and physiological time models. The Canadian Entomologist 108: 449-460.

Sutherland, O.R.W., R.F.N. Hutchins, and C.H. Wearing. 1974. The role of the hydrocarbon a-farnesene

in the behaviour of codling moth larvae and adults, pp. 249-263. Jn: L. Barton Browne, ed. Experi-

mental analysis of insect behavior. Springer Verlag, Berlin.

Toba, H.H. and J.F. Howell. 1991. An improved system for mass-rearing codling moth. Journal of the

Entomological Society of British Columbia 88: 22-27.

Van Leeuwen, E.R. 1947. Increasing production of codling moth eggs in an oviposition chamber. Journal

of Economic Entomology 40: 744-45.

Wearing, C.H. and R.F.N. Hutchins. 1973. a-Farnesene, a naturally occurring oviposition stimulant for

the codling moth, Laspeyresia pomonella. Journal of Insect Physiology 19: 1251-1256.

Zoller, B.G. 2001. Oviposition preference of codling moth between cut and uncut fruit of Bartlett, Bosc,

and Beurre Hardy cultivars in the Sacramento Valley. Proceedings of the Western Orchard Pest and

Disease Management Conference 75: 5-6.

Zoller, B.G. and A.M. Zoller. 2001. Biased sampling of codling moth oviposition using a cut fruit tech-

nique to monitor mating disruption in Bartlett pears. Proceedings of the Western Orchard Pest and

Disease Management Conference 75: 7-8.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 61

Use of Ethyl (£,2Z)-2,4-decadienoate in Codling Moth

Management: Kairomone Species Specificity

A.L. KNIGHT! and D.M. LIGHT’

ABSTRACT

Ethyl (£,Z)-2,4-decadienoate (pear ester) 1s a kairomonal attractant for both male and

female codling moth, Cydia pomonella (L.), in apple, pear and walnut. Studies were

conducted in the western Untied States to evaluate the potential attractiveness of this

kairomone for eight lepidopteran pests of these three crops, as well as, in cherry, peach/

nectarine, apricot, plum, almond, pistachio, grape, kiwi, and citrus. The pear ester was

loaded (10.0 mg) into gray halobutyl septa and insects were monitored with diamond- or

delta-shaped sticky traps. Lures were not attractive to peach twig borer, Anarsia

lineatella (Zeller); oriental fruit moth, Cydia molesta (Busck); omnivorous leafroller,

Platynota stultana Walshingham; navel orangeworm, Amyelois transitella (Walker);

apple fruitworm, Lacanobia subjuncta (Grote & Robinson); pandemis leafroller, Pan-

demis pyrusana (Kearfott); obliquebanded leafroller, Choristoneura rosaceana (Harris);

and western tentiform leafminer, Phy/lonorycter mespiella (Hiiebner). Additional stud-

ies with C. molesta populations attacking apple and pear would be useful.

Key Words: Cydia pomonella, Cydia molesta, pear ester, host plant volatiles, monitor-

ing

INTRODUCTION

Codling moth, Cydia pomonella (L.), is

the key pest of pears, apples, and walnuts

worldwide (Barnes 1991). Identification of

the pear ester, ethyl (£,Z)-2,4-

decadienoate, as a kairomone attractant for

adult and larval stages of codling moth has

allowed the development of several new

approaches to successfully monitor and

manage this pest (Light ef a/. 2001, Knight

and Light 2001; Knight et a/. 2002; Knight

et al. 2005). Pear ester is a characteristic

volatile of ripe pear (Jennings eft al. 1964)

and has not been detected in headspace

volatiles of unripe pear fruit and is not

known to be present in pear leaves (Shiota

1990, Miller et a/. 1989) or in walnut fruit

or leaves (Buttery et a/. 2000). However, it

has been detected as a minor constituent in

ripe ‘Red Delicious’ apple (Berger et al.

1984) and in quince (Schimizu and Yoshi-

hara 1977).

The attractiveness of pear ester for in-

sects other than codling moth has been

reported. The yellowjacket wasp Vespula

vidua (Saussure) was caught in low num-

bers in traps baited with pear ester (Day

and Jeanne 2001); and higher lure loadings

(> 40.0 mg) in gray halobutyl elastomer

septa are attractive to the western yellow

jacket, Vespula pennsylvanic (Saussure) 1n

apple (ALK, unpublished data). Low num-

bers of adult stink bugs, Fuschistus

conspersus Uhler, have occasionally been

observed in or near traps baited with >

20.0 mg pear ester septa (ALK and DML,

unpublished data).

The attractiveness of pear ester to other

lepidopteran species has also been re-

ported. Two polyphagous tortricid species,

Hedya nubiferana Haworth and Cydia fa-

"Yakima Agricultural Research Laboratory, Agricultural Research Service, USDA, 5230 Konnowac Pass

Rd., Wapato, WA 98951

7USDA, Agricultural Research Service, Western Regional Research Center, 800 Buchanan St., Albany,

CA 94710

62 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

giglandana (Zeller), were caught in traps

baited with pear ester in Swedish apple

orchards (Coracini et al. 2004) and in a

mixed apple and cherry orchard in Italy

(Schmidt et a/. 2004). In addition, the pest

species, Cydia splendana (Hiibner) was

caught in traps baited with pear ester in

chestnut orchards (Schmidt e¢ a/. 2004).

The attractiveness of pear ester to lepi-

dopteran pests sympatric with codling

moth in pome fruits and walnuts in western

North America has not been studied. This

complex of pest species includes tortricid

leafrollers, noctuid fruitworms and cut-

worms, and gracillarid leafminers (Beers ef

al. 1993; VanBuskirk et al. 1999). Six tor-

tricid leafroller species feed on the devel-

oping buds, leaves, and external surface of

apple and pear fruit: Choristoneura

rosaceana (Harris), Pandemis pyrusana

(Kearfott), Platynota stultana Walshing-

ham, Archips rosanus (L.), Argyvrotaenia

citrana (Fernald), and Archips argy-

rospilus (Walker). The western tentiform

leafminer, Phyllonorycter mespiella

(Hiiebner), 1s a common indirect gracillarid

feeding beneath the epidermis of apple and

pear leaves but causing little economic

damage to the crop. Several cutworm and

fruitworm noctuid species including Xestia

c-nigrum (L.) and Lacanobia subjuncta

(Grote & Robinson), are occasional pests

of apple and pear orchards and feed on

buds, leaves, and fruit (Barnett et al. 1991;

Landolt 1998). The oriental fruit moth,

Cydia molesta (Busck), is a key pest of

stone fruits attacking both developing

shoots and fruits (Rothschild and Vickers

1991). However, this species has expanded

its host range recently and has become a

significant pest of apple and pear in some

geographical regions (Civolani et al. 1998;

Usmani and Shearer 2001; IVichev ef al.

2003).

Many of these lepidopteran pest species

of pome fruit have a broad host range that

can include cherry, peach/nectarine, grape,

citrus, kiwi, and pistachio, as well as un-

cultivated hosts (Barnett et a/. 1991; Beers

et al. 1993). Host races of codling moth are

reported to sporadically attack other crops

such as plum, apricot, and almonds

(Barnes 1991) and have been reported to

attack cherry (Mote 1926). Within these

crops other important lepidopteran pests

can occur. The navel orangeworm, Amye-

lois transitella (Walker), attacks walnuts,

pistachios, and almonds (Barnett ef al.

1991). The peach twig borer, Anarsia

lineatella (Zeller), is another key pest dam-

aging shoots and fruits of almonds and

stone fruits (Barnes et al. 1993).

The objective of this study was to

evaluate the attractiveness of pear ester for

eight important lepidopteran pests that are

sympatric with codling moth among sev-

eral host crops in Washington and Califor-

nia. In addition, the attractiveness of pear

ester for P. stultana, C. molesta, and A.

lineatella was evaluated across a range of

crops that are not hosts for codling moth.

MATERIALS AND METHODS

Specificity Studies in Washington.

Studies were conducted in apple (n = 15),

pear (n = 10), cherry (n = 5), and peach (n

= 10) orchards during 1999 to evaluate the

species specificity of pear ester. Groups of

three diamond-shaped _ sticky traps

(Pherocon IIB, Trécé Inc., Adair, OK)

baited with gray halobutyl elastomer septa

(No. 1888, size No. 1, West Co., Phoenix-

ville, PA) loaded with either 10.0 mg pear

ester (93.7% A.I. purity, Aldrich Chemical,

Minneapolis, MN), sex pheromone

(proprietary loading, Trécé Inc., Adair,

OK), or a hexane solvent were spaced

more than 50 m apart and hung in the up-

per third of the canopy within each or-

chard. Studies were conducted in apple,

pear, cherry and peach orchards located

near Moxee, Wapato, and Brewster WA.

Lacanobia_ subjuncta and P. mespiella

were each monitored simultaneously in 10

pear orchards from 9 — 23 August and in

10 apple orchards from 16 — 30 August.

Traps baited with the sex pheromone of P.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

mespiella were not included in the pear

study. Pandemis pyrusana was monitored

in five apple and cherry blocks from 24 —

31 August. Choristoneura rosaceana was

monitored in five apple blocks from 9 — 16

September. Cydia molesta and A. lineatella

were monitored simultaneously in 10

peach orchards for 2 — 7 nights from 11

August to 7 September. Nontarget insects

caught in traps were counted and broadly

categorized by order (e.g. small dipterans,

dermapterans) or family or super family

(e.g. chrysopids, coccinellids, muscoid

flies). Numbers of adult white apple leaf-

hopper, Typhlocyba pomaria McAtee, and

codling moth were recorded for all traps in

apple and pear and for all crops, respec-

tively.

Specificity studies in California. Stud-

les were conducted from 18 August — 16

September 1999 in orchard blocks of

mixed cultivars of peach, apricot, plum,

almond, pistachio, grape, kiwi, and citrus

at the University of California campus in

Davis, CA; and at its germplasm repository

research station at Wolfskill in Winters,

CA. All crops except citrus were moni-

tored for P. stultana. Cydia molesta and A.

lineatella were monitored in all crops ex-

cept grape, kiwi and citrus. Amyelois tran-

sitella was present in the almond blocks

but was not specifically monitored due to

the ineffectiveness of the sex pheromone-

baited trap. Orchard blocks were moni-

tored with 10.0 mg pear ester, species’ sex

pheromone, and a trap baited with a sol-

vent blank lure placed in either wing-

shaped or diamond-shaped sticky traps

(Pherocon 1CP and IIB, Trécé Inc., Adair,

OK). Sex pheromone lures are commer-

cially available and were provided by

Trécé Inc. Traps were typically placed in

the mid canopy of orchards of each crop in

a randomized block design along 2 — 4

replicate orchard rows separated by 50 —

80 m.

Data analysis. Analysis of variance

(ANOVA) was used to detect significant

differences in mean moth catch per trap

per night among the sex pheromone, pear

ester, and solvent lures for each species, P

< 0.05 (Analytical Software 2000). Means

in significant ANOVA’s were separated

with a least significant difference test. A

paired t-test was used to compare the catch

of selected nontarget insects in traps baited

with pear ester or blank septa.

RESULTS

Specificity studies in Washington.

Species-specific sex pheromone-baited

traps caught male P. pyrusana, C.

rosaceana, L. subjuncta, P. mespiella, A.

lineatella, and C. molesta across apple,

pear, cherry, and peach orchards (Table 1).

Mean daily moth catches in these sex

pheromone-baited traps were significantly

higher than moth catches in traps baited

with pear ester or with blank lures. No

differences occurred in the catch of each of

these species in any crop between traps

baited with pear ester and blank lure-baited

traps. Low numbers of codling moth were

caught per day in traps baited with pear

ester in apple (0.24 + 0.04) (mean + SEM),

pear (0.10 + 0.06), cherry (0.03 + 0.03),

and peach (0.17 + 0.13), indicating the

pear ester lures were active.

Various other insect species were

caught in sticky traps baited with sex

pheromones, pear ester, or a blank lure:

including low sporadic numbers of ear-

wigs, lacewings, ladybird beetles, micro-

hymenopterans, and various species of

bees. Small dipteran species were com-

monly caught in traps though generally in

low numbers. The two most common non-

targets in apple and pear blocks in Wash-

ington during these trials were muscoid

flies (means of 4 — 5 flies per trap) and

white apple leafhopper, 7. pomaria

(means of 12 — 13 adults per trap). How-

ever, no significant difference in their den-

sities were found in traps baited with either

pear ester or blank lures for either group,

P’s = 0.48 and 0.61, respectively (paired t-

tests).

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

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solvent-baited traps in any crop other than

low catches of codling moth in blocks of

peaches, almonds, and citrus more than

California.

ies in

C. molesta, and P. stultana

Specificity stud

lineatella,

males were caught in sex pheromone-

100 m from pome fruit orchards. These

moth counts in the sex pheromone-baited

traps were all significantly different than

the zero catch in the pear ester-baited traps

(P’s < 0.01).

baited traps in peach, apricot, plum, al-

mond and pistachio orchards in California

(Table 2). In addition, male P. stultana

were trapped in grape and kiwi sites. No

moth species were caught in pear ester- or

DISCUSSION

pear (Knight ef a/. 2005). It also has dem-

onstrated potential to improve control via

The pear ester 1s a strong attractant for

codling moth adults and has improved

lure and kill approaches (Knight ef ai.

monitoring of this pest in walnut (Light ef

and disruption of oviposition

2002)

al. 2001), apple (Thwaite et a/. 2004), and

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 2.

Captures of moths in traps baited with either a conspecific sex pheromone, ethyl (2F,4Z)-2,4-

decadienoate (pear ester), or a blank lure in fruit orchards and vineyards 1n California.

Mean + SEM moths/trap/night

Conspecific sex pheromone’

Pear ester

Blank

Gop Anarsia Cues Platynota All other Cydia Solvent

lineatella stultana mothspecies pomonella Control

Peach 14.014+2.55 14.89+1.70 1.25+0.33 0 0.07 + 0.04 0

Apricot 10.68 +1.83 0.32+0.12 2.46+0.77 0 0 0

Plum 5.93 + 2.44 0.32+0.12 5.50+1.02 0 0 0

Almond 7.86+2.38 3.35+0.53 0.79+40.33 0 0.18+0.14 0

Pistachio 3.04+ 1.65 0.39+0.15 0.57+0.29 0 0 0

Grape - - 3.64 + 0.95 0 0 0

Kiwi - - 11.38 + 1.83 0 0 0

Citrus - - - 0 0.04 + 0.04 0

'Mean moth catch in sex pheromone-baited traps were all significantly different than moth

catch in pear ester-baited traps, P < 0.01 (ANOVA).

(Pasqualini et a/. 2004). Conversely, our

studies reported here have demonstrated

that pear ester is not attractive for eight

lepidopteran pest species of a number of

important horticultural crops in California

and Washington. The majority of these

lepidopteran pests either attack crops that

do not produce pear ester or feed and ovi-

posit primarily on foliage of pear or apple

that also lack pear ester. Species that are

known to be attractive to pear ester either

feed on ripe pear such as yellowjackets

(Akre and Davis 1979) and stink bugs

(Beers et al. 1993); share the major sex

pheromone component, (E£,£)-8,10-

dodecadien-1l-ol with codling moth, such

as C. fagiglandana and H. nubiferana, or

can detect this compound, such as C.

splendana (Schmidt et al. 2004), or have a

closely related sex pheromone, such as

methyl (£,Z)-2,4-decadieonoate for

Euschistus spp. stink bugs (Aldrich et al.

1991).

Among the various lepidopteran pests

in our study only C. molesta 1s a true inter-

nal fruit feeder that also attacks pear. Both

codling moth and C. molesta can also at-

tack quince (Cravedi and Ughini 1992),

another fruit that can release pear ester

(Schimizu and Yoshihara 1977). Pear host

races of C. molesta have been reported in

Australia (IV?ichev et al. 2003) and Italy

(Civolani et al. 1998); however, the attrac-

tiveness of pear ester for C. molesta in

these regions has not been examined. Ef-

forts to improve monitoring of C. molesta

populations, particularly in orchards

treated with sex pheromone mating disrup-

tion, have focused on the identification of

host plant volatiles attractive for females

(Natale et al. 2003). While adult popula-

tions of C. molesta trapped in peach, apri-

cot, plum, almond, and pistachios in our

study were not attractive to pear ester, sub-

sequent studies will evaluate the seasonal

attractiveness of pear ester for C. molesta

populations feeding on apple or pear.

66 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

ACKNOWLEDGEMENTS

We would like to thank Brad

Christianson, and Duane Larsen (U.S.D.A.,

A.R.S., Wapato, WA) for their help in

checking traps. Reviews by Wee Yee and

Peter Landolt (U.S.D.A., A.R.S., Wapato,

WA), Rick Hilton (Southern Oregon Ex-

sity, Central Point, OR), and from several

anonymous reviewers strengthened the

paper. This project received partial support

from the Walnut Marketing Board, Sacra-

mento, CA and Washington Tree Fruit

Research Commission, Wenatchee, WA.

perimental Station, Oregon State Univer-

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J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

Managing Codling Moth (Lepidoptera: Tortricidae) with an

Internal Grid of Either Aerosol Puffers or Dispenser

Clusters Plus Border Applications of Individual Dispensers

A.L. KNIGHT!

ABSTRACT

Field trials run from 2001 to 2003 evaluated the effectiveness of a combination of hand-

applied sex pheromone dispensers (Isomate-C) applied on the perimeter of apple or-

chards with an internal grid of either pressurized aerosol emitters (puffers) or clusters of

dispensers for control of codling moth, Cydia pomonella (L.). Puffers were placed in a

grid at 1 per ha, while the dispenser clusters were applied at 4 - 8 per ha. Puffers were

programmed to release either 240 or 360 mg (£, E)-8-10-dodecadienol (codlemone) per

day in 48 puffs (every 15 min from 1500 — 0300 h). Dispensers were grouped in clusters

of 50 (Isomate-C TT) or 100 (Isomate-C PLUS) releasing 56 and 33 mg codlemone per

d, respectively. No significant differences were found in levels of fruit injury in puffer-

treated orchards paired with similar orchards treated with 500 Isomate-C PLUS indi-

vidually applied dispensers per ha. Similarly no significant differences in fruit injury

were found in orchards treated with individually applied dispensers versus orchards

treated with Isomate-C PLUS dispensers (100 per cluster) placed in screened cages or

Isomate-C TT dispensers (50 per cluster) hung from plastic disks. Levels of fruit injury,

however, were significantly higher in orchards treated with Isomate-C PLUS dispensers

(100 per cluster) hung from plastic disks versus in orchards treated with individually

applied dispensers. This later poor performance of the Isomate-C PLUS clusters was

associated with its more restricted spacing of dispensers within the cluster and a signifi-

cant reduction in the weight loss of dispensers compared with dispensers applied indi-

vidually. These studies suggest that the use of puffers can effectively lower the cost of

codling moth management through reductions in sex pheromone puff volume and emit-

ter density.

Key Words: mating disruption, sex pheremones, puffers, apple

INTRODUCTION

Since 1990, uniformly distributed hand- Knight 1995a), material cost (Alway

applied dispensers loaded with (E, E)-8-

10-dodecadienol (codlemone) have been

the most commonly used approach to dis-

rupt mating of codling moth, Cydia pomo-

nella (L.) in North American tree fruit and

nut crops (Thomson ef al. 2000). Major

problems associated with the use of hand-

applied dispensers have been maintaining

the chemical stability of codlemone

(Brown et al. 1992; Millar 1995), seasonal

variability in emission rates primarily due

to changes in temperature (Howell 1992;

1997), and the labor cost of applying hun-

dreds of dispensers per hectare (Knight

1995b; Williamson ef al. 1996). High

emission, timer-activated mechanical aero-

sol dispensers (puffers) have been sug-

gested as an alternative that can solve

some of these problems (Mafra-Neto and

Baker 1996; Shorey et al. 1996; Isaacs et

al. 1999). Puffers are used at a low density,

can protect sex pheromones from UV deg-

radation and oxidation, allow the applica-

tion of a consistent pheromone release rate

Yakima Agricultural Research Laboratory, Agricultural Research Service, USDA, 5230 Konnowac Pass

Rd., Wapato, WA 98951

70 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

throughout the season, and allow users to

adjust the cycle and periodicity of sex

pheromone release (Shorey ef a/. 1996).

Shorey and coworkers postulated that

effective mating disruption depended on

the concentration of sex pheromone re-

leased per area and was not significantly

affected by the spacing between individual

point sources (Farkas eft al. 1974; Shorey er

al. 1996; Shorey and Gerber 1996a, b, c).

They showed that the distance between

pheromone sources could be quite large.

For example, a perimeter application of

emitters 100 m apart effectively disrupted

Platynota stultana (Walsingham) and Spo-

doptera exigua (Hibner) mating (Shorey ef

al. 1996).

Puffers were initially evaluated for cod-

ling moth in walnuts where tree height and

large canopy size had precluded the adop-

tion of hand-applied dispensers (Shorey

and Gerber 1996b). A single orchard was

treated with 2.3 puffers per ha with units

spaced 40 m apart along its perimeter.

Puffers were programmed to release ap-

proximately 5.0 mg codlemone per puff

every 30 min (254 mg/ha per d). Moth

catches in traps baited with synthetic lures

and virgin females were reduced 95 and

98% in this orchard versus in traps placed

in an untreated orchard (Shorey and Gerber

1996b). The current standard protocol for

codling moth control with puffers recom-

mends the use of 2.5 — 5.0 puffers per ha

arranged primarily around the perimeter of

orchards. However, in large blocks (> 16

ha) a few puffers are placed along the up-

wind interior of the orchards (Elkins

2002).

Four major problems have occurred

with the use of puffers for management of

codling moth. First, placement of puffers

on the perimeter of orchards has not been

effective in preventing injury along the

upwind edges of the orchards (Shorey ef

al. 1998). Greater wind speed and turbu-

lence plus higher moth population density

along orchard borders are problematic with

this approach (Milli et al. 1997). A second

problem has been their high cost. The fixed

cost of individual cabinets housing the

electronics ($40 amortized over 5 y) plus

the yearly cost of the disposable phero-

mone-loaded canisters ($80) often limits

the number of units deployed. Hand-

applied dispensers in Washington State are

typically applied at rates of 500 per ha and

cost $125 per ha (Alway 1997). To be cost

competitive puffer density should be 1.5 —

2.0 units per ha. A third problem has been

the loss of units during the season due to

wind, vandalism, and a variety of mechani-

cal malfunctions. The unreliable perform-

ance of puffers has required expensive

maintenance and frequent monitoring of

units (Knight 2002). A fourth problem has

been the occurrence of severe marking of

fruit and foliar phytotoxicity surrounding

units due to incidental contact with the sex

pheromone solution (Giroux and Miller

2001).

An alternative approach was developed

that alleviates some of these constraints

(Knight 2002). Orchards are treated with

an internal grid of puffers spaced 50 m

from the border and 100 m apart (one

puffer per ha) in combination with a pe-

rimeter application of hand-applied dis-

pensers (1,000 per ha). This design was

tested in apple orchards for codling moth

alone or codling moth and obliquebanded

leafroller, Choristoneura rosaceana

(Harris), using canisters loaded with the

sex pheromone of both species (Knight

2002). This method provided good control

of both pests at a lower cost per ha than the

use of uniformly distributed hand applied

dispensers. However, these studies were

only conducted in large, regular-shaped

orchards with flat terrain and have not suf-

ficiently addressed the utility of this ap-

proach in smaller, irregular-shaped or-

chards with sloping topography (Knight

2002). The initial success of this approach

also suggests that lower puffer volumes of

sex pheromone should be evaluated. Un-

fortunately, problems with the reliability of

the puffer units and phytotoxic effects per-

sisted in this study and grower adoption

has been slowed by these problems. An

alternative design has been proposed that

would replace the mechanical puffers with

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

clusters of hand-applied dispensers to gen-

erate high emission point sources (Knight

2002).

Herein, I report results from field

evaluations conducted in apple from 2001-

03 using grids of both puffers and clusters

of dispensers to manage codling moth.

Studies were conducted with puffers emit-

ting two rates of sex pheromone and with

four types of clusters that varied in dis-

penser density, dispenser type, and dis-

penser spacing within the cluster. Results

demonstrate that an internal grid of widely

spaced emitters can be effectively used as

part of an integrated management approach

for codling moth and can further reduce

the costs associated with using sex phero-

mones.

MATERIALS AND METHODS

Studies were conducted in 20 — 60 ap-

ple orchards of several cultivars (primarily

‘Delicious’, ‘Fuji? and ‘Granny Smith’)

near Brewster, WA each year from 2001-

03. All orchards evaluated in 2001 were 16

ha with level terrain. Orchards in 2002-03

varied in size from 4.0 — 16.0 ha and very

often were irregular in shape with a moder-

ately sloping terrain (3.0 — 6.0° slope).

Field trials were conducted to evaluate

the effectiveness of a combination of hand-

applied sex pheromone _ dispensers

(Isomate-C PLUS, Pacific Buiocontrol,

Vancouver, WA) applied on the perimeter

of apple orchards with an internal grid of

either pressurized aerosol emitters

(puffers) or clusters of hand-applied dis-

pensers (Isomate C Plus and Isomate C TT,

Pacific Buiocontrol, Vancouver, WA).

Puffer cabinets (Paramount Puffer", Para-

mount Farming, Bakersville, CA) were

spaced in an internal 100 x 100 m grid (1

per ha) beginning 50 m from the edges of

the orchard. Orchards treated with clusters

of dispensers received four clusters of dis-

pensers per ha spaced in an internal 50 x

50 m grid, except for five orchards in 2003

that were treated with eight clusters of dis-

pensers per ha spaced 35 x 35 m apart.

Cluster grids were spaced beginning 25 m

from the edge of the orchard. The perime-

ter of these orchards was also treated with

a 10-20 m wide band of hand-applied

Isomate-C PLUS dispensers at a rate of

1,000 dispensers per ha.

Puffers were evaluated in 2001 and

2002 in 22 orchards. The cabinet of puffers

is constructed of high-density polyethylene

plastic (32 x 15 x 12 cm) and powered by

four ‘AA’ batteries. Puffer operation was

controlled by a remote controller and puff-

ers operated only at temperatures > 10 °C.

Cabinets were mounted on wood blocks

and attached with a metal clip to trees in

the upper third of the canopy. Puffer can-

isters are pressurized metal cylinders

loaded with either a 25.0% or a 16.7%

solution of codlemone plus solvents and

propellants. Canisters emit a 30 mg spray

through a solenoid-metered valve every 15

min from 1500 — 0300 h. Studies were

conducted in 2001 with puffers emitting

either a 7.5 or 5.0 mg A.I. dose

(codlemone). Studies in 2002 tested only

the 5.0 mg dose.

The effectiveness of using clusters of

Isomate-C dispensers was evaluated in 39

orchards from 2001-03. Two different

polyethylene Isomate-C dispensers were

used in clusters, Isomate-C PLUS and

Isomate-C TT. Both dispensers are loaded

with a 60:33:7 blend of (E, £)-8-10-

dodecadien-1l-ol, dodecanol, and tetradeca-

nol. Isomate-C PLUS and Isomate-C TT

dispensers were loaded with 182.3 and

382.4 mg active ingredients, respectively.

Only Isomate-C PLUS dispensers were

used in 2001 and they were clustered in

square, screened boxes (19.0 x 19.0 x 21.0

cm). One hundred dispensers were placed

vertically in the screened boxes in alternat-

ing cells and were spaced on average (SE)

2.4 (0.1) cm apart. The screened sides of

the box had a 0.41 cm’ mesh and the ends

of the box were constructed with a 0.10

cm’ screen to prevent dispensers from fal-

ling out. Plastic bucket lids (21.7 cm di-

ameter) were used to hold clusters of dis-

72 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

pensers during 2002-03. The plastic lids

had either 100 slits (0.15 x 0.7 cm) or 50

0.48 cm-diameter holes cut in the lids for

Isomate-C PLUS or Isomate-C TT dis-

pensers, respectively. One end of each dis-

penser was inserted vertically into the plas-

tic lid. The mean (SE) spacing of Isomate-

C PLUS and Isomate-C TT dispensers

hanging from the lid was 1.3 (0.2) cm and

3.0 (0.2) cm, respectively. Studies were

conducted with Isomate-C PLUS in 13

orchards in 2002 and with Isomate-C TT in

11 and 10 orchards in 2002 and 2003, re-

spectively. During 2003 five orchards each

were treated with four or eight clusters per

ha. The screened boxes and plastic lids

were attached to poles with wire hangers.

Clusters of dispensers were placed in the

upper third of the canopy.

Comparison orchards (controls) were

selected each year and paired with or-

chards treated with puffers or dispenser

clusters. Orchard pairs were selected based

on similarity in size, proximity, cultivar,

ownership, spray practices and pest pres-

sure (based on percent fruit injury the pre-

vious year). All comparison orchards were

treated with Isomate-C PLUS dispensers

applied at a rate of 500 dispensers per ha.

Pheromone lure-baited delta-shaped

traps were deployed in all orchards at a

density of 1 per 2 ha placed around the

perimeter of each orchard 10 m from the

edge. Orchards treated with dispenser

clusters in 2001 and 2003 plus the associ-

ated comparison orchards were also moni-

tored with two (2001) or three (2003) pear

ester-baited traps placed 50 m from the

edge of orchards and >100 m from the

nearest trap. Pear ester lures were used in

these two studies to provide a second

measure of moth population density that

would be more independent of the sex

pheromone treatment. Trécé Inc. (Adair,

OK) provided all monitoring traps and

lures. Traps were placed in the upper third

of the orchards’ canopy using a permanent

PVC pole. Sex pheromone-baited traps

were checked weekly and pear ester-baited

traps were checked every 4 wk. Lures were

replaced after 8 wk and removable sticky

trap liners were replaced as needed.

Pre-harvest fruit injury was assessed by

sampling 30 fruit from 20 trees selected

within each quadrant of each orchard

(2,400 fruit sampled per orchard). An

equal number of fruit were sampled from

the interior and from the edge (< 30 m

from the perimeter) of each quadrant.

Spray records were obtained from the

growers and field managers at the end of

each season.

The weight loss of each dispenser type

for dispensers applied individually or

within a cluster was analyzed in 2002. Six

new dispensers of each type were weighed

on 29 April. Isomate-C Plus dispensers

were then twisted on to a plastic clip and

attached to branches in a pear orchard.

Isomate-C TT dispensers were placed over

branches in the same orchard. Five new

dispensers were randomly selected from

the outer rim and five from the center of

four clusters and were weighed. Clusters

were hung individually in pear trees spaced

10 m apart. All dispensers were reweighed

on 25 September.

Statistical analysis. Mean moth catch

per trap, number of insecticide sprays ap-

plied for codling moth, and percent fruit

injury in orchards treated with uniformly

distributed individual dispensers versus

grids of puffers or dispenser clusters were

analyzed with the Wilcoxon Rank Sum test

(Analytical Software 2000). The mean

daily weight loss for dispensers applied

individually or placed in the middle or

outer rim of clusters in 2002 was analyzed

for each dispenser type with a Kruskal-

Wallis test (Analytical Software 2000).

RESULTS

No significant differences were found

for mean moth catch, number of insecti-

cide sprays applied, and codling moth fruit

injury between puffer-treated and individu-

ally applied dispenser-treated orchards at

either puffer emission rate (Table 1). Ap-

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 73

Table 1.

Summary data for paired apple orchards treated with either an internal grid of one aerosol

puffer per ha plus a perimeter treatment of Isomate-C PLUS dispensers or 500 Isomate-C

PLUS dispensers per ha. Puffers released either 5.0 or 7.5 mg sex pheromone per puff. No

significant differences were found in moth catch, number of insecticide sprays applied, and

percent fruit injury between the paired puffer and Isomate-treated orchards, Wilcoxin Signed

Rank tests, two-tailed P-value > 0.05.

; Mean (SE) Mean (SE) Mean (SE)

Puff: eee

Sve Year (no. moth catch per trap no. sprays % fruit injury

(mg) orenaras) Puffers | Dispensers Puffers Dispensers Puffers Dispensers

7.5 2001 (10) 1.5(0.8) 2.5(€1.1) 0.8(0.2) 0.9(0.2) 0.22 (0.15) 0.20 (0.12)

5.0 2001 (5) 4.3(1.8) 5.7(2.1) 1.3(0.4) 2.4(0.6) 0.20(0.13) 0.54 (0.20)

5.0 2002 (7) 6.9(1.9) 7.8(3.6) 1.5(0.4) 1.4(0.4) 0.12 (0.03) 0.08 (0.07)

5.0 All(12) 5.8(1.5) 6.9(3.0) 1.4(0.2) 1.8(0.3) 0.15 (0.06) 0.27 (0.11)

ple orchards had low codling moth popula-

tion densities as evidenced by low cumula-

tive moth catches in sex pheromone-baited

traps (< 10 moths per season) (Table 1).

Growers supplemented their use of puffers

and dispensers with 1 — 3 insecticide

sprays per season. Insecticides applied for

codling moth included azinphosmethyl,

phosmet, and methoxyfenozide. Nearly

half of all sprays were applied only to the

borders of orchards.

Orchards treated with clusters of dis-

pensers had similar moth catches and sup-

plemental insecticide sprays applied as

orchards treated with individual dispensers

during all three years (Table 2). Codling

moth fruit injury in orchards treated with

individually applied dispensers paired with

orchards treated with either screened box

clusters with Isomate-C Plus or plastic lid

clusters of Isomate-C TT dispensers were

not significantly different in any of the

three years (Table 2). However, fruit injury

was significantly higher during 2002 in

orchards treated with plastic lid clusters of

Isomate-C Plus dispensers than in the

paired orchards treated with individually

applied dispensers (Table 2). During 2003,

orchards treated with 4.0 and 8.0 clusters

per ha loaded with Isomate-C TT dispens-

ers had similar levels of codling moth in-

jury as orchards treated with 500 or 1,000

dispensers per ha, respectively (Table 2)

The mean weight loss of dispensers

within plastic lid clusters versus those indi-

vidually applied varied between dispenser

type (Table 3). No difference was found in

the mean weight loss of Isomate-C TT

dispensers placed in clusters versus dis-

pensers applied individually. The mean

daily emission rate of codlemone from

these clusters during the season averaged

55.6 mg. In comparison, Isomate-C Plus

dispensers in both the center and edge of

clusters loss significantly less weight dur-

ing the season than dispensers applied indi-

vidually (Table 3). The mean daily emis-

sion rate of codlemone from these clusters

averaged only 32.7 mg during the season.

DISCUSSION

These studies show that treating or-

chards with a high-density application of

dispensers on the perimeter and a widely

spaced grid of high emission emitters inter-

nally can be substituted for the application

of hundreds of individually applied dis-

pensers to manage codling moth in apple.

The use of either pressurized canisters re-

leasing puffs of sex pheromone every 15

min or the continuous passive diffusion of

74 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

Table 2.

Summary data for paired apple orchards treated with either an internal grid of clusters of

Isomate-C dispensers at 4.0 or 8.0 clusters per ha plus a perimeter treatment of Isomate-C

PLUS dispensers or treated with 500 — 1,000 Isomate-C PLUS dispensers per ha. Clusters were

baited with either 100 Isomate-C PLUS or 50 Isomate-C TT dispensers.’

Mean (SE) moth catch per trap

Treatment per ha’ Mean (SE) Mean (SE)

(# paired orchards) Sex pheromone Kairomone 10. cover sprays % fruit injury

2001

4 C-Plus box clusters (5) 2.0 (0,9) 3.0 (1.0) 0.8 (0.2) 0.00 (0.00)

500 C-Plus dispensers 2.8 (0.8) 3.4 (0.7) 1.0 (0.0) 0.12 (0.06)

2002

4 C-TT lid clusters (11) 8.4 (2.7) - 1.5 (0.5) 0.15 (0.08)

500 C-Plus dispensers 10.1 (3.6) - 2.0 (0.5) 0.14 (0.06)

4 C-Plus lid clusters (13) 10.7 (2.9) - 1.6 (0.4) 0.14 (0.06)**

500 C-Plus dispensers 6.5 (2.1) - 1.8 (0.4) 0.05 (0.03)**

2003

8 C-TT lid clusters (5) 2.4 (1.5) 8.8 (6.1) 1.8 (0.4) 0.20 (0.20)

1,000 C-Plus dispensers 1.2 (0.6) 2.2 (0.6) 1.8 (0.4) 0.00 (0.00)

4 C-TT lid clusters (5) 2.6 (1.6) 4.8 (1.9) 1.4 (0.6) 0.13 (0.10)

500 C-Plus dispensers 7.4 (5.9) 3.8 (2.6) 1.8 (0.4) 0.00 (0.00)

'««*? Pyalue < 0.01, two-tailed Wilcoxin Signed Rank test. All other statistical comparisons

were not significant, P > 0.05.

One hundred Isomate C-PLUS dispensers were placed in screened boxes in 2001 and attached

to plastic lids in 2002. Fifty Isomate C-TT dispensers were attached to plastic lids in 2002-03.

Table 3.

Mean (SE) weight loss (mg per d) of dispensers aged in the field, 29 April - 25 September

2002'

Dispenser on the outer

Individual Dispenser in the

mispensct dispenser center of cluster rim of cluster Bryan

Isomate-C TT 1.74 (0.11) 1.84 (0.04) 1.87 (0.05) O52

Isomate-C PLUS 0.71 (0.08)a 0.56 (0.02)b 0.53 (0.02)b < 0.01

‘Row means followed by a different letter were significantly different, P < 0.05, Kruskal-

Wallis one-way nonparametric analysis of variance using a chi-squared approximation.

approach for codling moth where dispens-

ers are applied only to the perimeter of

orchards has not been tested.

Most of the orchards treated with sex

sex pheromone from clusters of dispensers

were both effective. Charmillot et al.

(1995) used a perimeter-only application

of sex pheromone dispensers to reduce

injury from Lobesia botrana Denis &

Schiffinmiiller in vineyards, and they were

the first to suggest a grid design. A similar

pheromones in these studies were also

sprayed with insecticides for control of

codling moth. Thus it is not possible to

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

assess the effectiveness of the sex phero-

mone treatments alone. In general, sex

pheromone is considered to be an impor-

tant part of an integrated management pro-

gram for codling moth, and can rarely be

used as a single control tactic (Brunner ef

al. 2002). The latest survey of insecticide

usage in Washington State reported that on

average three to four sprays are applied for

codling moth (National Agricultural Statis-

tical Service 2002). Many orchards in the

Brewster area have been treated with three

to six insecticide applications in the past

few years due to increased pest populations

(A.L.K., unpublished data). Based on

these data the use of sex pheromone in our

study reduced insecticide use 40-60%

compared with conventionally treated or-

chards.

Nearly half of all insecticides were ap-

plied only to the borders of orchards in our

study. Codling moth injury most com-

monly occurs on the borders of orchards

regardless of whether orchards are treated

with hand-applied dispensers (Pfeiffer ef

al. 1993), treated with puffers placed on

the perimeter (Elkins 2002), or treated only

with insecticides (Madsen eft al. 1975).

Effective disruption of codling moth along

border areas will remain problematic due

to this area’s reduced canopy structure and

greater wind speed and turbulence that can

reduce the sex pheromone concentration

(Milli et a/. 1997). Trimble and Vickers

(2000) found that codling moth could be

effectively managed over a three-year pe-

riod in Ontario apple orchards with only

border insecticide applications. The inte-

gration of border sprays with an internal

grid of puffers/clusters may be an effective

management alternative that has not yet

been evaluated.

The internal grid design has several

operational advantages over the standard

hand application of hundreds of dispensers

per hectare including cost savings and ease

of use. Grouping the same number of dis-

pensers into clusters reduced application

costs up to 35% among growers that I sur-

veyed. Yet, this savings for growers was

minimal because application costs for

hand-applied dispensers are low, $15 for

500 dispensers per ha (Knight 1995b). The

application and servicing of puffers was

not measured in this study but was re-

ported earlier to be only $3 per puffer

(Elkins 2002). The material cost of the

puffer grid design was slightly less expen-

sive than the use of reduced rates of hand-

applied dispensers ($111 versus $125 per

ha), except for the high fixed cost of the

remote control ($350).

Further reductions in the cost of an ef-

fective management program using clus-

ters of dispensers are unlikely. Clusters

loaded with 100 Isomate-C Plus dispensers

did not perform as well as the standard

program and were estimated to release 30

mg codlemone per d. Clusters with 50

Isomate-C TT dispensers released 40%

more codlemone per d than clusters of 100

Isomate-C PLUS and provided effective

control. Further evaluation of clusters

loaded with 30 — 50 Isomate-C TT dis-

pensers might establish a minimum thresh-

old needed with this design. However, the

complex interplay of factors impacting the

population dynamics of codling moth in

commercial pheromone-treated orchards

would likely obscure any marginal im-

provement in performance. Instead, addi-

tional cost savings can more likely be

achieved by reducing the amount of sex

pheromone loaded in puffers.

The amount of sex pheromone loaded

in Paramount Puffers® used in Washing-

ton State orchards could be reduced 50%

by lowering the pheromone puff from 7.5

to 5.0 mg and the longevity of the phero-

mone loading in the canister from 200 to

150 d. Unlike in California, the flight pe-

riod of codling moth lasts approximately

150 d from late April to mid September in

Washington State. Further refinements in

the arrangement of puffers especially when

supplemented with insecticides could fur-

ther reduce the cost. Studies have shown

that individual puffers can disrupt male

codling moth orientation to traps placed

200 — 450 m downwind (Shorey and Ger-

ber 1996b, Cave et al. 2001), and suggest

that their density could be reduced to one

76 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

per several hectares. Puffer densities could

likely be reduced in large, contiguous

plantings. For example, the density of puff-

ers declined from 4.0 to 2.8 per ha as the

size of an area wide pear project in Lake

County, California increased from 100 to

531 ha over a five-year period (Elkins

2002).

Puffers have been demonstrated to be

an effective tool to manage codling moth

under a variety of deployments (Elkins

2002, Knight 2002). The use of dispenser

clusters was developed as an alternative

due to the unreliability of puffers (Knight

2002). Yet, the characteristics of dispens-

ers currently limit the maximum emission

rate of codlemone from clusters. Thus,

increasing the emission rates from clusters

or the density of clusters will also increase

the cost of this approach. Puffers allow

greater flexibility in adjusting the emission

rate and timing of release. Improvements

in the operation and reliability of puffers

will enhance their adoption. The use of an

internal grid design may allow the devel-

opment of a lower cost, effective manage-

ment program for codling moth to be de-

veloped.

ACKNOWLEDGEMENTS

We thank Brad Christianson, Duane

Larson, and Kathi Johnson (U.S.D.A.,

A.R.S., Wapato, WA) for their help in con-

ducting these tests. Mitch Trimble, Ag

Canada, Vineland, Ontario; Doug Light,

U.S.D.A., Albany, CA; and Tom Larsen,

Suterra LLC, Bend, OR, provided helpful

comments. This project was_ partially

funded by the Washington Tree Fruit Re-

search Commission, Wenatchee, WA.

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J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004 79

Improved Deposition and Performance

of a Microencapsulated Sex Pheromone

Formulation for Codling Moth (Lepidoptera: Tortricidae)

with a Low Volume Application

A.L. KNIGHT! and T.E. LARSEN?

ABSTRACT

Experiments were conducted to evaluate the deposition pattern and effectiveness in dis-

rupting male orientation to virgin female-baited traps of a microencapsulated sex phero-

mone formulation for codling moth, Cydia pomonella (L.) in apple, Malus domestica

Bordhausen. The efficacy of two application techniques was evaluated in field trials

with the microencapsulated formulation Checkmate® CM-F: a high volume (926 liters

per ha) application with an air blast sprayer and a low volume (46 liters per ha) applica-

tion with a custom-built vertical boom sprayer. These treatments were compared to an

unsprayed control and a control treatment where the formulation was applied directly on

the ground within the plots. Disruption of virgin female-baited traps was significantly

greater in the low volume versus the air blast application and versus the two types of

control plots. Levels of disruption in the air blast-sprayed plots were not different from

untreated plots or in plots where the sprayable sex pheromone was applied directly on

the ground. A significant increase in the proportion of traps catching moths occurred in

week 4. A significant interaction occurred among the effects of spray method, tree can-

opy position, and leaf surface on microcapsule deposition. This interaction was likely

due to the low rate of deposition of microcapsules on the undersides of leaves in the

lower canopy with the low volume sprayer. The low volume sprayer deposited signifi-

cantly more microcapsules in the upper canopy than the air blast sprayer. Significantly

more microcapsules were deposited on the underside versus the top of leaves in the up-

per canopy with the air blast but not with the low volume sprayer.

Key Words: sex pheromone, mating disruption, apple, pest management

INTRODUCTION

Various techniques have been devel-

oped to achieve mating disruption of cod-

ling moth, Cydia pomonella (L.), by treat-

ing orchards with controlled release de-

vices (Vickers and Rothschild 1991). The

use of sex pheromones in the western U.S.

has been adopted rapidly since 1991 and is

used on nearly 40,000 ha in Washington

State alone (Brunner ef al. 2002). Various

hand-applied dispensers registered for cod-

ling moth have accounted for > 90% of this

treated acreage (Thomson ef al. 2000).

Concurrently, microencapsulated sprayable

formulations have been tested for codling

moth (Knight 2000), but have not yet been

widely adopted.

The ease of applying microcapsules

with conventional equipment is a major

factor generating grower’s interest in

sprayables (Campion 1976, Doane 1999).

Sprayable sex pheromone formulations

allow pest managers to treat crops with tall

canopies, such as walnuts, and they in-

crease grower’s flexibility in adjusting

application rates and timings during the

season. In addition, microcapsules can be

tank-mixed with other pesticides and can

easily be included within a grower’s inte-

"Yakima Agricultural Research Laboratory, Agricultural Research Service, USDA, 5230 Konnowac Pass

Rd., Wapato, WA 98951

* Suterra LLC, 213 SW Columbia Street, Bend, OR

80 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

grated control program.

Conversely, a major limitation affecting

the adoption of sprayable pheromone for-

mulations has been their relatively short

residual activity (Farbert et a/. 1997). The

emission profile from microcapsules typ1-

cally exhibits a large initial burst followed

by a sharp decline (Hall and Marrs 1989).

Microcapsules for codling moth have been

applied every four weeks during the grow-

ing season, but significant disruption of

moth catches may occur for only one to

two weeks (Knight 2000). Any efforts to

extend the current activity of microcap-

sules will speed the adoption of this tech-

nology for codling moth management.

A large number of factors are likely

involved in the successful use of microcap-

sules, including their emission profile over

time, their structural integrity, the chemical

stability of the sex pheromone, and density

initially deposited and retained over time

in the active area of the crop.

Surprisingly little is known about how

these factors affect the performance of

sprayable formulations for codling moth.

The addition of antioxidant and UV stabi-

lizers has reportedly improved the chem1-

cal stability of codlemone within a spray-

able formulation (Eng et a/. 2003). Labora-

tory studies have shown that differences in

the epicuticular wax layer and the degree

of pubescence of various plant tissues can

affect microcapsule deposition rates in

apple (Waldstein and Gut 2003, Knight ef

al. 2004). In addition, water has been

shown to be a major factor causing dis-

lodgement of microcapsules from leaves

(Knight et a/. 2004). Other factors, such as

wind, abrasion, or other environmental

factors impacting microcapsule retention

under field conditions have not been inves-

tigated.

Adjusting one or more application pa-

rameters to increase either the deposition

and/or retention of microcapsules over

time may be a useful approach to extend

the efficacy of sprayables for codling

moth. Increasing the rate of application

would likely also increase the density of

microcapsules deposited in the canopy, but

this approach 1s restricted by the compara-

ble costs of alternative pest management

tactics. Applying the same total rate of sex

pheromone per season using more frequent

applications of low rates of sprayables has

been an effective compromise for some

pest / crop systems (Polavarapu ef al.

2001), but have not been successful in lim-

ited tests with codling moth (Hull ef al.

2004). An additional parameter that may

improve the performance of sprayables

over time could be the refinement of the

application technique.

Many pesticides including sprayables

are applied in tree crops as concentrated

sprays in spray volumes of 500-1,000 li-

ters/ha using high velocity, air blast spray-

ers (Barnett et a/. 1991). The use of these

concentrated sprays can reduce application

costs and avoid excessive leaf run-off as

well as spray drift out of the orchard. Vari-

ous factors on the sprayer are adjusted to

generate a uniform spray coverage within

the canopy, including tractor speed, spray

velocity, and nozzle number, orifice size,

and orientation (Byers et al. 1984). Pesti-

cides are typically not applied with spray

volumes <500 liters/ha in pome fruit or-

chards due to the difficulty in attaining

good spray coverage (Byers ef al. 1984).

Similarly, microcapsule formulations have

not been applied in tree fruits in spray vol-

umes <500 liters/ha because they are

thought to achieve mating disruption by

camouflaging the calling of virgin females

with a uniform ‘fog’ of sex pheromone

(Doane 1999). Herein, we examine the

influence of two spray application tech-

niques on the pattern of deposition of

microcapsules and their efficacy in disrupt-

ing the sexual communication of codling

moth in apple, Malus domestica Bord-

hausen.

MATERIALS AND METHODS

Studies were conducted to compare the

efficacy of applications of Checkmate®

CM-F (Suterra LLC, Bend, OR), a micro-

encapsulated sex pheromone, with either

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

an air blast or a low volume sprayer in a 35

yr-old “Red Delicious’ apple orchard situ-

ated near Naches Heights, WA from 10

July to 08 August 2000. Twelve 0.25 ha

plots separated by 75 m were established

within the orchard and randomly assigned

one of four treatments: air blast application

of sex pheromone; air blast application of

water as a control; low volume application

of sex pheromone; and a low volume ap-

plication of sex pheromone directly on the

ground as a second control. The latter

treatment was included to experimentally

assess the impact of microcapsules that are

not deposited on the foliage following a

canopy spray application. Plots consisted

of 48 trees (6.8 x 8.0 m tree spacing).

Mean + SE tree height was 4.3 + 0.1 m.

Sex pheromone-treated plots were sprayed

with a 50:50 mixture of microcapsules

containing 14.3% codlemone and micro-

capsules formulated with 0.50% of a fluo-

rescent material "Dye-Lite" (Tracer Prod-

ucts, Westbury, NY). Codlemone was ap-

plied in all plots at a rate of 49.0 g a.i. per

ha. A Victair Mistifier (H. F. Hauff Co.,

Yakima, WA) sprayer with a 100-liter tank

pulled by an all-terrain vehicle (ATV) was

used to apply the air blast application of

sex pheromone and of water alone. Seven

spray nozzles angled at 45 ° and positioned

on the sprayer at heights from 1.1 to 1.7 m

applied 10.4 liters per minute at 686 kilo-

pascals. Plots were sprayed at a rate of 926

L/ha. The low volume sprayer consisted of

a 95-liter polyolefin tank mounted on an

ATV. The sprayer was rigged with an

adjustable vertical spray boom outfitted

with two flat fan nozzles. Nozzles were

positioned on the boom at a height of 3.1

m and angled upward at a 45° angle. The

two nozzles together deliver a spray vol-

ume of 2.36 liters per minute at 18 kilopas-

cals. Plots were sprayed at a rate of 46 L/

ha. A horizontal boom attached to the ATV

at a height of 1.0 m was used to apply the

ground application of sex pheromone and

fluorescent materials (49.0 g a.i. per ha)

with the same nozzles at the same low vol-

ume rate used in the canopy.

The density of fluorescent microcap-

sules on the ground was estimated by plac-

ing five plastic cards (18 x 35 cm) beneath

the tree canopy prior to the spray applica-

tion. Cards were collected < 2 h after

sprays were applied, returned to the labora-

tory, and the number of microcapsules was

counted under UV illumination (Black-Ray

Long Wave Ultraviolet Lamp, Ultra-Violet

Products, Inc., San Gabriel, CA). Cards

placed in plots where the material was

sprayed directly on the ground were sub-

sampled. Cards were first subdivided into

ten 7 x 9 cm squares and the number of

microcapsules was counted in one ran-

domly selected square from each card.

The density of fluorescent microcap-

sules per leaf in the canopy was sampled in

both the air blast and low volume-treated

plots by collecting five leaves from 10

trees in each replicate from both low (2.2

m) and high (3.2 m) positions in the cano-

pies. Leaves were bagged and microcap-

sules on both the top and bottom leaf sur-

faces were counted under UV light in the

laboratory.

The efficacy of treatments in disrupting

codling moth was evaluated with the use of

virgin female-baited traps. Ten wing-

shaped sticky traps (Pherocon 1CP, Trécé

Inc., Salinas, CA) were placed in each plot

spaced approximately 10 m apart and 10 m

from the edge. Traps were baited with two

virgin female codling moths (< 3 d-old and

maintained at 5.0 + 0.5 °C) placed inside a

screened PVC cage (4.2 cm [O.D.] x 5.5

cm) hung inside from the top of each trap.

Traps were checked and females were re-

placed every three to four days. T he

proportion of traps not catching any male

moths was used as a measure of mating

disruption within each treatment.

Data Analysis. A repeated-measures

analysis of variance (ANOVA) was used to

compare the proportion of virgin female-

baited traps catching male moths with

treatment as the between subject factor and

week as the within subject factor

(Analytical Software 2000). These propor-

tional data were transformed prior to

analysis with arcsine (square root [x]). A

three-way ANOVA was used to evaluate

82 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

the density of microcapsules on leaves

with spray application, leaf surface (top or

bottom surfaces), and canopy height (low

and high) as the main effects. Significant

means in all ANOVA’s were separated

with a least significant difference test, P <

0.05. The distribution of microcapsule

density between each spray method was

compared with a Kolmogorov-Smimov

test (Analytical Software 2000).

RESULTS

Significant differences in disruption of

male capture in female-baited traps were

found among plots sprayed either with an

air blast or a low volume sprayer, plots

where the sex pheromone was sprayed on

the ground, and unsprayed plots (F = 6.72;

df = 3, 8; P < 0.05) (Table 1). Significant

differences were also found in levels of

disruption among weeks (F' = 30.84; df =

3, 9; P < 0.001) (Table 1). The interaction

of treatment and time was not significant

(P = 0.42). Disruption of sexual communi-

cation was significantly higher in the low

volume-treated plots than the other treat-

ments. No difference in the male capture

in female-baited traps occurred in plots

treated with either the air blast sprayer,

applying the sex pheromone directly on the

ground, or the application of only water.

The proportion of traps catching moths

among treatments was significantly lower

during the first three weeks of the study

versus week four (Table 1).

The density of microcapsules deposited

on the ground beneath the trees varied

among the three sex pheromone treatments

(F = 78.20; df = 2, 6; P< 0.001). The high-

est mean + SE density of microcapsules

was in plots where the sex pheromone was

sprayed directly on the ground, 4.5 + 0.8

per 10 cm’ and was significantly different

from the microcapsule densities on the

ground in the canopy-treated plots sprayed

with either an air blast, 0.05 + 0.02 per 10

cm’ or a low volume sprayer, 0.14 + 0.05

per 10 cm’. The density of microcapsules

on the ground was not significantly differ-

ent between the two canopy spray treat-

ments.

The mean density of microcapsules

deposited in the lower and upper tree can-

opy and on the top and bottom surfaces of

leaves varied with both spray methods

(Fig. 1). The significant three-way interac-

tion for canopy position * leaf position *

spray method (F = 7.61; df = 1, 16; P <

0.05) appears to be the result of low micro-

capsule deposition on the lower leaf sur-

Table 1.

Mean + SE proportion of virgin female-baited traps catching male codling moths in plots

treated with microencapsulated sex pheromone (49 g a.i. per ha) applied with either an air blast

or low volume sprayer in the canopy or a low volume sprayer on the ground versus water con-

trol in replicated 0.25 ha apple plots, July — August 2000."

Proportion of traps catching moths

Overall week

Low volume Low volume

No. weeks

post-spray Water control ot

cano

I 0.30(0.06) 0.13 (0.07)

y 0.43 (0.07) 0.43 (0.17)

3 0.13(0.13) 0.23 (0.07)

4 0.90(0.10) 0.83 (0.03)

Oneal 0.44 (0.07)a_ 0.41 (0.09)a

treatment means

means

cano round

0.03 (0.03) 0.30 (0.15) 0.19 (0.05)c

0.23 (0.03) 0.53 (0.09) 0.41 (0.06)b

0.03 (0.03) 0.23 (0.03) 0.15 (0.04)c

0.63 (0.03) 0.70 (0.12) 0.77 (0.05)a

0.23 (0.08)b 0.44 (0.09)a

‘Column and row overall means followed by a different letter were significantly different,

repeated measures analysis of variance, P < 0.05, LSD.

A. Upper canopy

a) a: | ~e

(2) Ge 7.

5 845 Pa

25 oe

+| se ig ®

cB 3 a

ce a2 ;

os é

ies O

1- a

Oise eee

Air blast Tow volume

Mean + number of

. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

4 jase

B. Lower canopy

334

5 O..

62 =e

3 ..

n Jue

as _ ..

oO Se

14 e.0O i

n 4

Tow volume

Air blast

Figure 1. The mean + SE number of microcapsules deposited on the top (e—e) or bottom (0-

-©) surface of leaves in the upper (A) and lower canopy (B) of apple trees sprayed with either

an air blast or low volume sprayer.

face in the bottom of the canopy when

applied with the low volume sprayer (open

symbols Fig. 1B). We conducted one-way

ANOVA on simple effects means to com-

pare spray methods and to compare leaf

surfaces in only the top of the canopy. A

significantly greater number of microcap-

sules were deposited per leaf with the low

volume (mean + SE = 7.5 + 1.4) versus the

air blast (mean + SE = 3.0 + 0.7) applica-

tion in the upper canopy (F = 16.40; df= 1,

4; P < 0.05). The difference in microcap-

sule density was significant between upper

and lower leaf surfaces for the air blast

sprayer (F' = 214.02; df = 1, 4; P < 0.0001)

with more microcapsules on the lower leaf

surface, but not with the low volume

sprayer (/'=3.69; df= 1,4; P=0.13).

The overall distribution of microcap-

sule densities per leaf in the canopy did not

differ significantly between spray methods

(K-S statistic = 0.10, P = 0.09) (Fig. 2).

The highest microcapsule density per leaf

in the plots treated with the low volume

and air blast sprayer ranged up to 116 and

17 microcapsules per leaf, respectively.

Five percent of the leaves sampled in the

low volume-treated plots had > 20 micro-

capsules and these were all in the upper

canopy.

DISCUSSION

Spray application method was found to

have a significant effect on the efficacy of

Checkmate® CM-F for codling moth. An

air blast application did not increase the

disruption of virgin female-baited traps

more than an untreated check or when the

material was sprayed directly on the

ground. This result is consistent with the

poor performance of this formulation in a

series of grower field trials using air blast

sprayers conducted from 2001-2003 (A. L.

K., unpublished data). In contrast, a low

volume application to the canopy provided

significant levels of disruption during a

four-week trial.

The difference in efficacy observed

between spray methods was associated

with differences in microcapsule deposi-

tion. The low volume application deposited

significantly more capsules than the air

blast spray in the upper canopy. The sexual

activity of codling moth is generally re-

stricted to the upper canopy and mating

disruption is enhanced when sex phero-

mone dispensers are placed in the upper

versus in the lower canopy (Weissling and

Knight 1995). The low volume application

also treated 5.0% of leaves with more than

20 microcapsules. The potential for these

leaves to serve as attractive point sources

and enhance “false-trail following” by

male codling moths has not been explored.

In general, the emission rate of sex phero-

mone from individual or clumps of micro-

capsules has been thought to be too low to

create an attractive point source (Sanders

84 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

@ Low volume © Air blast

Percentage of leaves

oS)

0 1 to 5

6to10 11 to1l5 16 to 20

ey <—y 3

No. microcapsules per leaf

Figure 2. Frequency distribution of microcapsule density per leaf in plots sprayed with either

an air blast or low volume sprayer.

1997). Instead, microcapsule formulations

are thought to achieve mating disruption

by camouflaging the calling of virgin fe-

males with a uniform ‘fog’ of sex phero-

mone (Doane 1999). However, the mean

diameter of the Checkmate® CM-F 1s ap-

proximately 100 um, which 1s much larger

than many of the formulations (<< 5 um)

used in earlier studies (Bakan 1980). Addi-

tional research will determine if leaves

with variable numbers of microcapsules

are attractive to codling moth and whether

the low volume application of microcap-

sules may increase its effectiveness by

enhancing the role of “false-trail follow-

ing”.

Factors influencing the deposition of

microcapsules due to differences in spray

practices are not understood. The two can-

opy spray methods used in our trials dif-

fered in several ways including water vol-

ume (20-fold difference) and spray pres-

sure (40-fold difference). However, it is

not clear how these factors influence the

deposition of microcapsules on foliage.

Previous studies have found that the struc-

tural integrity of these microcapsules is not

impaired by high velocity spray applica-

tions (T. E. L., unpublished data). Interest-

ingly, no difference was found in the depo-

sition of microcapsules on the ground be-

neath trees with either canopy spray appli-

cation method. The addition of adjuvants

could perhaps improve the deposition of

microcapsules on leaves with either spray

method. Laboratory tests have found that a

latex sticker significantly increased deposi-

tion and retention of microcapsules on

dipped apple leaves before and after simu-

lated rainfall (Knight et al. 2004).

The height and angle of the spray noz-

zle may also affect the deposition pattern

within the canopy, i.e., the low deposition

of microcapsules on the underside of

leaves in the lower canopy in plots treated

with the low volume sprayer. Laboratory

studies have found that significantly more

microcapsules are deposited on the under-

side versus the top of apple leaves with

dipped leaves (Knight et a/. 2004). This

pattern was clearly seen in the upper can-

opy with the air blast but not with the low

volume spray application. Lowering the

vertical boom of the low volume sprayer

and aiming the spray stream upwards into

the canopy would likely increase the depo-

sition of microcapsules on the underside of

leaves. Microcapsules deposited on the

underside of leaves typically have greater

longevity due to shading effects (Hall and

Marrs 1989). This may be especially 1m-

portant with conjugated dienes such as

codlemone due to their sensitivity to isom-

erization and oxidation (Millar 1995). The

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

addition of UV stabilizers has significantly

extended the longevity of the Checkmate®

CM-F microcapsules; however, the effects

of shading provided by the undersurface of

apple, pear, or walnut leaves has not been

reported (Eng ef al. 2003).

The compatibility of microencapsulated

sex pheromone products with other pesti-

cides has been one factor used to promote

their use (Doane 1999). Air blast sprayers

apply materials at very high velocities (150

- 300 km/h) to generate a uniform cover-

age of small droplets throughout the can-

opy. Most pesticides during the season are

applied as concentrated sprays (< 1,000

liters per ha) due to significant reductions

in spray costs versus dilute applications

(Barmett et al. 1991). Yet, this study sug-

gests that applying a sprayable sex phero-

mone formulation for codling moth is not

effective with these standard spraying

methods. Difficulties in spraying orchards

late in the season with standard equipment

could be an important factor limiting the

adoption of sprayable pheromone in apple.

The low volume sprayer pulled by an ATV

allowed orchard rows with a closed canopy

to be sprayed without dislodging fruit. The

density and deposition patterns of micro-

capsules should be evaluated with the use

of alternative spray methods, such as air-

craft, handgun sprayers, or herbicide

sprayers. Further reductions in spray vol-

ume with these various methods should

also be considered.

ACKNOWLEDGEMENTS

We thank Brad Christianson, (U.S.D.A.,

A.R.S., Wapato, WA) and Kristin Ketner

(Suterra LLC, Bend, OR) for their help in

conducting these tests. Dave Horton

(U.S.D.A., A.R.S., Wapato, WA) provided

advice for statistical analyses. Also special

thanks to Pete Garza (Manzana Orchards,

Moxee, WA) for allowing us to use his

orchards. Helpful comments were provided

by Arthur Agnello, Cornell University,

Geneva, NY; Steve Arthurs, U.S.D.A.,

Wapato, WA; and Doug Light, U.S.D.A.,

Albany CA. This project was partially

funded with funds supplied by the Wash-

ington Tree Fruit Research Commission,

Wenatchee, WA.

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Bakan, J.A. 1980. Microencapsulation using coacervation/phase separation techniques, pp. 83-105. Jn A.

F.Kydonieus, ed., Controlled release technology: methods, theory, and applications. CRC Press, Boca

Raton, FL.

Barnett, W.W., W.J. Bentley, R.S. Bethell, C. Pickel, P.W. Weddle, and F.G. Zalom. 1991. Managing

pests in apples and pears, pp. 21-53. Jn M. L. Flint, ed., Integrated pest management for apples and

pears. Publication 3340. University of California Press. Oakland, CA.

Brunner, J., S. Welter, C. Calkins, R. Hilton, E. Beers, J. Dunley, T. Unruh, A. Knight, and R.Van Steen-

wyk. 2002. Mating disruption of codling moth: a perspective from the Western United States. Interna-

tional Organization of Biological Control Western Palaeartic Regional Section Bulletin 25(9): 11-21.

Byers, R.E., C.G. Lyons, K.S. Yoder, R.L. Horsburgh, J.A. Barden, and S.J. Donohue. 1984. Effects of

apple tree size and canopy density on spray chemical deposit. Horticultural Science 19: 93-94.

Campion, D.G. 1976. Sex pheromones for the control of lepidopteran pests using microencapsulated and

dispenser techniques. Pesticide Science 7: 636.

Doane, C.C. 1999. Controlled-release devices for pheromones, pp. 295-317. In H. B. Scher, ed., Con-

trolled-release delivery systems for pesticides. Marcel Dekker, Inc., New York.

Eng, J.A., E. Holmes, T. Larsen, S. Stadlmann, and K. Ketner. 2003. Effects of sunlight on encapsulated

sprayable codling moth pheromone, p. 9. Jn Proceedings 77” Western Orchard Pest and Disease Man-

agement Conference, 15-17 January 2003, Portland, OR. Washington State University, Wenatchee,

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Farbert, P., U.T. Koch, A. Farbert, and R.T. Staten. 1997. Measuring pheromone concentrations in cotton

fields with the EAG method, pp. 347-358. Jn R. T. Carde and A. K. Minks, (eds.), Insect pheromone

research: new directions. Chapman & Hall, New York.

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(eds.), Insect pheromones in plant protection. John Wiley and Sons Ltd., New York.

Hull, L.A., C. Myers, and G. Krawazyk. 2004. Low rate-frequent applications of sprayable pheromone for

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Knight, A.L. 2000. Applying sex pheromones - from puffers to air-blast sprayers. Proceedings of the

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Knight, A.L., T.E. Larsen, and K.C. Ketner. 2004. Rainfastness of a microencapsulated sex pheromone

formulation for codling moth (Lepidoptera: Tortricidae). Journal of Economic Entomology 97: 1987-

1992.

Millar, J.G. 1995. Degradation and stabilization of E8,E10-dodecadienol, the major component of the

sex pheromone of the codling moth (Lepidoptera: Tortricidae). Journal of Economic Entomology 88:

1425-1432.

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665.

Sanders, C.J. 1997. Mechanisms of mating disruption in moths, pp. 333-346. Jn R. T. Carde and A. K.

Minks, (eds.), Insect pheromone research new directions. Chapman & Hall, New York.

Thomson, D., J. Brunner, L. Gut, G. Judd, and A. Knight. 2000. Ten years implementing codling moth

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Vickers, R.A. and G.H. Rothschild. 1991. Use of sex pheromones for control of codling moth, pp. 339-

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mies and control. Elsevier, Amsterdam, The Netherlands.

Waldstein, D.E. and L.J. Gut. 2003. Comparison of microcapsule density with various apple tissues and

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J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Persistence of a commercial codling moth

eranulovirus product on apple fruit and foliage

J.E. COSSENTINE”” and L.B.M. JENSEN!

ABSTRACT

Codling moth, Cydia pomonella (L.), larval bioassays were carried out on apples and

leaves collected from trees treated with the commercially available codling moth granu-

lovirus, Virosoft CP4*, to estimate the persistence of the product over time. The virus

had a significant effect on survival of laboratory derived codling moth larvae placed on

apples collected up to five and eight days post-treatment. Larvae died with virus symp-

toms after feeding on treated foliage and the leaf bioassay was easier to count than the

apple bioassay. A combination assay, exposing larvae to leaf discs and fruit may more

accurately account for potential exposure of wild neonate codling moth to virus in

treated orchards. The addition of fish, soybean or mineral oils to Virosoft CP4* treat-

ments did not significantly increase the efficacy or persistence of the viral insecticide on

apples in this study.

Key Words: Virosoft CP4®, leaf discs, Cydia pomonella

INTRODUCTION

The codling moth granulovirus (CpGV)

(Baculoviridae) is found in wild and colo-

nized codling moth (Cydia pomonella (L.),

Lepidoptera: Tortricidae) (Tanada 1964;

Eastwell et al. 1999) which 1s a major pest

of apples and pears throughout most of the

temperate world (Cross et al. 1999). CpGV

is noted for its high virulence when 1n-

gested by this host, particularly in the neo-

nate stage (Sheppard and Stairs 1976;

Tanada and Leutenegger 1968). Commer-

cial formulations of the virus have been

registered for use against the codling moth

in Europe since 1988 and in the U.S.A.

since 1995. In 2000, Virosoft CP4®, pro-

duced by BioTepp Inc., Quebec, became

registered for use on apples and pears in

Canada.

Commercial formulations of CpGV

require application of aqueous suspensions

of the virus onto the apples and foliage of

treated trees. There is a relatively short

time when a wild codling moth can be ef-

fectively exposed to CpGV treatment in an

orchard. Most wild codling moth eggs are

Oviposited on leaves (Jackson 1979). Neo-

nates move over leaf surfaces before find-

ing a fruit and chewing through the surface

where they remain, feed and develop

through to the last instar. Ballard ef al.

(2000) found that CpGV was ingested by

codling moth neonates browsing on CpGV

treated leaf surfaces, therefore there is the

potential for codling moth neonates to en-

counter and ingest lethal levels of CpGV

on both treated foliage and fruit surfaces.

Orchard trials of various commercial

preparations of CpGV_ have generally

shown good early suppression of neonate

codling moth (Glen and Payne 1984;

Jaques et al. 1987). However, like other

viral insecticides, the CpGV 1s susceptible

to inactivation and dilution due to tempera-

ture, exposure to sunlight, and precipita-

tion (Jaques 1975, 1985; Glen and Payne

1984). CpGV has been found to be 50%

inactivated in 2-8 d on apples (Glen and

Payne 1984; Jaques eft al. 1987; Arthurs

and Lacey 2004).

The goal of this study was to determine

Agriculture and Agri-Food Canada, PARC, Summerland, BC, Canada VOH 1Z0

* Corresponding author:cossentinej@agr.gc.ca

88 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

the persistence of Virosoft CP4” on apples

and foliage under the orchard conditions in

the interior of British Columbia (BC), Can-

ada. We also evaluated whether various

oils, added to the spray mixture, could in-

crease or extend the duration of the Viro-

soft CP4"'s efficacy under orchard condi-

tions, by possibly improving coverage and

increasing the penetration of the virus

through the leaf surface.

MATERIALS AND METHODS

All treatments were applied to a high

density (1m tree spacing within rows) or-

chard of MacIntosh apple trees at the Pa-

cific Agri-Food Research Centre, Summer-

land, BC.

Virulence of Virosoft CP4 over time

on apples and leaves. Two blocks of five

rows of high density apple trees were

treated with Virosoft CP4° at 239 ml/ha

(original preparation: 4x10'° occlusion

bodies/946.34 ml) on 12 June, 2003 using

an air-blast sprayer set to deliver a volume

of 2,347.6 L/ha. The Virosoft CP4® was

stored refrigerated. An untreated block of

trees separated by > 30 trees in the same

orchard was used as the control. Two hours

after application of the virus, 10 leaves and

apples were randomly collected from the

treatment and the control. Similar collec-

tions were made 1, 4, 6, 8, and 12 days

after application of the treatments. The

entire trial was replicated on different

blocks of trees within the same orchard on

3 July, 2003. Mean + SE daily tempera-

tures during the orchard collection (12-24

June:17.6 + 3.0 °C; 3-15 July: 22.5 + 2.3

°C) and the accumulated daily rain that

occurred during the June (0.6 + 1.1 mm/d)

and July replications (0 + 0 mm/d) were

similar to daily temperatures (18.8 + 4.1

°C) and precipitation (0.7 + 2.3 mm/day)

for this area, from 1 June to 15 July, aver-

aged over a 5 y period (1999 - 2004)

(Anon. 2004).

Codling moth neonates used in the as-

says emerged on the same day that the

leaves and apples were collected, from egg

sheets obtained from the colony of the

Okanagan-Kootenay Sterile Insect Release

Program (Osoyoos, BC). Five neonate cod-

ling moth were placed on the stem end of

each collected apple. The apples were

sealed in plastic cups and incubated at 24

°C, 16:8 h L:D before codling moth sur-

vival was assessed by cutting open the fruit

on days 7 and 14. The total number of live

larvae in the apple bioassays was a more

accurate assessment of the impact of the

virus than percentage mortality as larvae

occasionally could not be found. Some

neonates naturally move off the apple and

die by dessication without feeding in apple

assays (Laing and Jaques 1980); others

disintegrate beyond recognition due to a

viral infection or are difficult to locate.

One disc (1 cm diameter) was cut from

each leaf, avoiding the center vein, within

an hour of their collection and placed on a

layer of stikem (Stikem Special'™, Phero-

Tech Inc., Delta, BC) in a small plastic

petri dish. Ten codling moth neonates were

placed on each leaf disc. The discs, with

the larvae, were placed in the dark for 60

minutes at 22 + 1 °C to encourage feeding.

Larvae that had consumed leaf material

frequently had green coloured alimentary

canals, green frass and a portion of the leaf

surface was scarred. Five larvae which

showed evidence of feeding per leaf were

transferred to the surface of a pinto-bean

based diet (modified from Shorey and Hale

1965) within individual 30-ml plastic cups.

The cups were sealed and incubated at 24

°C, 16:8 h L:D until the number of living

larvae was assessed on days 7 and 14. Data

were analysed using an ANOVA (SAS

2000) and the means were separated within

each day the apples or leaves were col-

lected with individual ANOVAs and

Tukey’s studentized range test.

Virosoft CP4 + oils. In a separate ex-

periment, four blocks of four rows of high

density apple trees were each treated with

Virosoft CP4" alone at 239 mil/ha

(original preparation: 4x10’ occlusion

bodies/946.34 ml), Virosoft CP4” 239 ml/

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

ha + mineral oil (Superior 70 oil, United

Agri Products, Dorchester, ON) at 2L/ha,

Virosoft CP4® 239 ml/ha + fish oil

(Crocker’s Fish Oil, Inc., Quincy, WA) at

2L /ha or Virosoft CP4” 239 ml/ha + once

descummed soybean oil at 2.5 L/ha, 17

June, 2004 using an air-blast sprayer set to

deliver a volume of 1,553.6 L/ha. A block

of untreated trees separated by >10 trees in

the same orchard was used as the control.

Ten apples were randomly collected from

each treatment and the control at least two

hours after application of treatments on

day 0, as well as 1, 2, 5, 7, and 10 days

post-treatment. The entire trial was repli-

cated on 28 June 2004 on different blocks

of trees within the same orchard. Mean +

SE daily temperatures during the orchard

collection (17-27 June 2: 22.4 + 2.5 °C; 28

June to 8 July: 17.3 + 3.4 °C) and the accu-

mulated rain that occurred during the first

(2.1 + 5.5 mm/day) and second replication

(0.8 + 1.3 mm/day) are similar to mean

daily temperatures and precipitation for

this area, averaged over 5 y, as recorded

above. Bioassays were carried out using

codling moth neonates on the collected

apples as described above. The number of

living larvae were counted seven days post

exposure. Data were analysed as described

for the previous study.

RESULTS AND DISCUSSION

Efficacy of Virosoft CP4 over time on

apples and leaves. The Virosoft CP4® had

an overall significant impact on the num-

ber of codling moth able to survive the

virus treatment, compared to control lar-

vae, when the data were collected both 7

and 14 days post-exposure to field col-

lected apples (7 d: Fi.2. = 77.6, P <

0.0001; 14 d: F;..= 66.7, P < 0.0001).

Significantly fewer codling moth larvae

survived for seven days in apples from

trees treated with the virus, compared to

untreated apples, two hours, and 1, 4, and 8

days post-treatment with Virosoft CP4”

(Table 1). This significant difference be-

tween the number of living larvae in the

treated versus control apples was extended

to 12 days post-treatment when the data

were read on day 14, except in apples col-

lected four days post-treatment (Table 1).

The number of live codling moth larvae

found both in untreated and treated apples

was generally lower over all days, when

the assays were read at 14 versus 7 days,

due to the difficulty locating larvae in the

fruit at the later date. The apples had to be

carefully sectioned to find the larvae and

long term larval mortality data may have

been influenced by decay in the fruit. The

disappearance and death of a small number

of larvae may be partially due to mortality

caused by a colony derived CpGV infec-

tion and subsequent disintegration of the

dead larvae (personal observation). As this

mortality would occur in both treated and

control apples any differences in surviving

codling moth would be attributable to the

treatment. Some additional virus-induced

death would be expected to occur between

days 7 and 14, however, the poor survivor-

ship of larvae in decaying control apples

decreases the value of data obtained at this

later date.

Codling moth larvae died after consum-

ing CpGV in leaf disc assays and Virosoft

CP4” had a significant impact on the num-

ber of codling moth larvae able to survive

the virus treatment, compared to control

larvae (7 d: F, 26 = 12.6, P <0.0005; 14 d:

Fi 26 = 7.5, P <0.0007). Significantly

fewer living codling moth larvae were

found when larvae fed on leaf discs col-

lected two hours and one day post-

treatment from Virosoft CP4® treated trees,

compared to discs from untreated leaves

(Table 1). Similar results were found when

the number of surviving larvae were

counted 7 and 14 days post-exposure. The

leaf disc bioassay was easier to count than

the apple bioassay as more larvae were

found in the former.

The difference in the active persistence

of the virus determined in the apple and

leaf disc bioassays is probably due to neo-

90 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

Mean + SE number of live codling moth larvae found per apple or leaf disc after 7 and 14 days

when neonates were placed on Virosoft CP4™ treated or control apples or leaf discs. Replicated

twice; n= 10 apples or leaves; 5 codling moth larvae per apple and leaf disc.

Mean + SE number of live codling moth larvae per apple and leaf disc

Days post-

treatment Read 7 days post-exposure Read 14 days post-exposure

Virosoft CP4® Control Virosoft CP4® Control

Apples

0 (2h) 0.9+0.2a! 24+0.3b 0.2+0.1a 1.6+£0.3b

l O72=02a 3.140.3b 0.8+0.3a 1740.3 b

4 162024 3.140.3b Le 03 54 19+0.4a

6 26+0.3a 322024 0.9+04a 3.0+0.3b

8 2520.2 4 55202 3 I220224 2.922026

12 2.8+0.3a 3.44+0.3a 2.1403 a 3.0+0.3b

Leaf discs

0 (2h) 2.9403 a 4340.2b 222038 3.6+0.2b

l 4.2+0.2a 48+0.1b 3.34 0.3'4 42+0.2b

4 43+0.2a 46+0.la 3.4403a 40+0.2a

6 4.8+0.la 48+0.la 41+0.2a 3.9+0.2a

8 452024 4520.24 At 02-2 3.9+0.3a

12 46+0.2a 46+02a 41+0.2a 3.9+0.2a

'Means within rows and days post-exposure followed by the same letter are not significantly

different (P > 0.05), determined with Tukey’s studentized range test (SAS 2000).

nates feeding more readily and extensively

on the surface of the apple than on the foli-

age. Glen and Clark (1985) found that 90%

of codling moth neonates hatching from

eggs on leaves spent more than 10 min on

leaves before moving to the fruit. Penetra-

tion of fruit by codling moth has been re-

corded to take 1 to 2.5 h (Geier 1963). As

the neonates in our study were held for 60

minutes on a leaf disc before transferring

them to the diet, each neonate had a realis-

tic, but limited chance to ingest the virus.

Ballard et al. (2000) did not observe feed-

ing by codling moth neonates on leaf tissue

until neonates were left for 15 minutes. It

is also possible that more virus is accumu-

lated near the stem and the calyx ends of

apples (Arthurs and Lacey 2004) and many

of the codling moth neonates choose these

areas of the apple to feed and then pene-

trate. Most wild codling moth would en-

counter CpGV on both the leaf and apple

surfaces, therefore it would be appropriate

to improve these assays by exposing neo-

nates to both treated surfaces to obtain a

more realistic assessment of potential mor-

tality in the orchard.

Virosoft CP4 + oils. The virus treat-

ments had a significant effect on survival

of codling moth larvae (F425 = 32.2, P

<0.001). Significantly fewer living codling

moth larvae were found in apples collected

two hours, one day, and five days post-

treatment from trees treated with Virosoft

CP4® alone, or in combination with any of

the oils, than in the control apples. In ap-

ples collected two, seven and ten days

post-treatment, this difference was not

significant (Table 2). Although the mean

numbers of live codling moth larvae per

apple in Virosoft CP4® treatments in com-

bination with an oil was lower on days 0

and 1, the numbers were not significantly

lower than those in the Virosoft CP4®

treatment alone.

The virulence of the Virosoft CP4®

applied in June and early July, under con-

ditions that are typical for the southern

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004 9}

Table 2.

Mean + SE number of live codling moth larvae per apple after 7 days when neonates were

placed on fruit treated with Virosoft CP4" combined with one of three oils, or nothing. Repli-

cated twice; n= 10 apples; 5 codling moth larvae per apple.

Mean + SE number of live codling moth larvae per apple per treatment

Days post- ; ; ® ; ® ‘ ®

treatanent Virosoft Virosoft CP4° + Virosoft CP4 Virosoft CP4

® ; ; : : . Control

CP4 Superior 70 oil + Fish oil + Soybean oil

0 (2h) 1.1+40.4a! 0.6+0.la 0.3+02a 0.3+02a 3.9+0.5b

| 12+03a 0.7+0.la 11+03a 0.7+02a 3.7+0.5b

2 182+0.5a 1.8+0.5a Lis0.1a 16+1.0a 3.5+0.la

5 2.0+0.7a 16+0a 20+02a 19+0.2a 3.9+0.4b

7 2.4+0.7a 192+0.5a 22+£0.7 a 2.00+0.la 3.1+09a

10 20+02a 19+0a 2.3+0.4a 2.0+0.5a 3.1+04a

'Means within rows followed by the same letter are not significantly different (P > 0.05) as

determined with Tukey’s studentized range test (SAS, 2000).

interior of BC, decreased quickly over time

in both trials. In orchard trials in Washing-

ton State, Arthurs and Lacey (2000) found

a similar decline in activity and estimated a

Virosoft CP4” (3.2 oz/ac) half-life on ap-

ples to be 3.8 to 8.7 d_ post June and July

recognize that our study was carried out

using colony derived larvae and that wild

codling moth larvae may feed on treated

apple tree leaves and fruit differently under

orchard conditions, which may modify the

impact of the virus on the host.

treatments, respectively. It 1s important to

ACKNOWLEDGEMENTS

We are grateful to B. Tiffin (Pacific

Agri-Food Research Centre, Summerland)

for applying the treatments in the orchard.

REFERENCES

Anon. 2004. PARC Summerland weather. Http://res2.agr.ca/parc-crapac/summerland/ clim/index_e.htm.

Arthurs, S.P. and L.A. Lacey. 2004. Field evaluation of commercial formulations of the codling moth

granulovirus: persistence of activity and success of seasonal applications against natural infestations

of codling moth in Pacific Northwest apple orchards. Biological Control 31: 388-397.

Ballard, J., D.J. Ellis and C.C. Payne. 2000. Uptake of granulovirus from the surface of apples and leaves

by first instar larvae of the codling moth Cydia pomonella L. (Lepidoptera: Olethreutidae). Biocontrol

Science and Technology 10: 617-625.

Cross, J.V., M.G. Solomon, D. Chandler, P.J. Jarrett, P.N. Richardson, D. Winstanley, H. Bathon, J.

Huber, B. Keller, G.A. Langenbruch and G. Zimmermann. 1999. Review of biocontrol of pests of

apples and pears in northern and central Europe: 1. Microbial agents and nematodes. Biocontrol Sci-

ence and Technology 9: 125-149.

Eastwell, K.C., J.E. Cossentine and M.G. Bernardy. 1999. Characterization of Cydia pomonella granu-

lovirus from codling moths in a laboratory colony and in orchards in British Columbia. Annals of

Applied Biology 134: 285-291.

Geier, P.W. 1963. The history of the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), in

the Australian Capital Territory. Australian Journal of Zoology 11: 323-367.

Glen, D.M. and J. Clark. 1985. Death of Cydia pomonella larvae and damage to apple fruit, after field

application of codling moth granulosis virus. Entomologia Experimentalis et Applicata 38: 93-96.

Glen, D.M. and C.C. Payne. 1984. Production and field evaluation of codling moth granulosis virus for

control of Cydia pomonella in the United Kingdom. Annals of Applied Biology 104: 87-98.

Jackson, D.M. 1979. Codling moth egg distribution on unmanaged apple trees. Annals of the Entomologi-

92 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

cal Society of America 72: 361-368.

Jaques, R.P. 1975. Persistence, accumulation and denaturation of nuclear polyhedrosis and granulosis

viruses, pp. 90-99. Jn M.D. Summers, R. Engler., L.A. Falcon, and P. Vail (Eds), Baculoviruses for

Insect Pest Control: Safety Considerations. American Society for Microbiology, Washington DC.

Jaques, R.P. 1985. Stability of insect viruses in the environment, pp. 285-360. Jn K. Maramorosch and

K.E. Sherman (Eds) Viral Insecticides for Biological Control. Academic Press, New York.

Jaques, R.P., J.E. Laing, D.R. Laing and D.S.K. Yu. 1987. Effectiveness and persistence of the granulosis

virus of the codling moth Cydia pomonella (L.) (Lepidoptera: Olethreutidae) on apple. The Canadian

Entomologist 119: 1063-1067.

Laing, D.R. and R.P. Jaques. 1980. Codling moth: techniques for rearing larvae and bioassaying granulo-

sis virus. Journal of Economic Entomology 73: 851-853.

SAS 2000. Proc GLM Users Manual Version 8.1. SAS Institute, Cary, NC.

Sheppard, H. H. and G.R. Stairs. 1976. Effects of dissemination of low dosage levels of a granulosis virus

in populations of the codling moth. Journal of Economic Entomology 69: 583-586.

Shorey, H.H. and R.L. Hale. 1965. Mass-rearing of the larvae of nine noctuid species on a simple artificial

medium. Journal of Economic Entomology 58: 522-524.

Tanada, Y. 1964. A granulosis virus of codling moth, Carpocapsa pomonella (Linnaeus) (Olethreutidae,

Lepidoptera). Journal of Invertebrate Pathology 6: 378-380.

Tanada, Y. and R. Leutenegger. 1968. Histopathology of a granulosis-virus disease of the codling moth,

Carpocapsa pomonella. Journal of Invertebrate Pathology 10: 39-47.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

Species of ground beetle (Coleoptera: Carabidae)

in organic apple orchards of British Columbia

R.F. SMITH’, J.E. COSSENTINE’, S.M. RIGBY’

and C.S. SHEFFIELD!

ABSTRACT

In a two year study, 14 genera of Carabidae (Agonum Bonelli, Amara Bonelli, Anisodac-

tylus Dejean, Bembidion Latreille, Carabus Linné, Harpalus Latreille, Lebia Latreille,

Loricera Latreille, Poecilus Bonelli, Prerostichus Bonelli, Scaphinotus Dejean, Stenolo-

phus Stephens, Syntomus Hope and Trechus Clairville) represented by 44 species were

identified from six commercial organic apple orchards in the southern Similkameen

valley in British Columbia, Canada; 13 of these species were not native to the area. The

4,299 specimens were caught in ‘ramp’ pitfall traps, with the genera Prerostichus and

Harpalus comprising 56% and 43%, respectively. Numbers of Carabidae ranged from

11-21 species per orchard, with their presence detected throughout the collection period.

Key Words: Carabidae, diversity, abundance, organic orchards, British Columbia

INTRODUCTION

In North America there are 168 genera

and over 2200 species of ground beetle

(Coleoptera: Carabidae), most of which are

predaceous as adults and larvae (Arnett

1993). Carabids are common in tree fruit

orchards (Edwards 1998) and many other

agricultural (Levesque and Levesque 1994;

Raworth et al. 1997) and natural ecosys-

tems (Brumwell et a/. 1998; Toft and Bilde

2002). Their function as polyphagous

predators within orchards was recognized

in the 1800's (Lord 1983), and several spe-

cies are known to prey on key tree fruit

pests (MacPhee ef al. 1988; Pearsall and

Walde 1994; Sunderland 2002). Eight

species have been reported to feed on lar-

vae of codling moth, Cydia pomonella (L.)

(Lepidoptera: Tortricidae), one of the key

pests of pome fruit in Canada (Hagley and

Allen 1988; Riddick and Mills 1994).

Carabids are also considered good indi-

cators of ecological change in different

communities (Niemeld et al. 1993; Nie-

mela and Kotze 2000; Szyszko et al. 2000;

Holland 2002; Holland et a/. 2002). Un-

fortunately, many pesticides induce signifi-

cant levels of mortality in carabids

(Eptsein et al. 2000; Smith et al. 2000;

O’Flaherty 2002) and lower levels of fe-

cundity (H. Goulet, Eastern Cereal Oil

Research Centre, Ottawa, Ontario, pers.

comm.) thereby impacting their potential

for natural biological control in agricul-

tural systems. Despite the significance of

carabids in orchard habitats there have

been few published studies of species di-

versity in the 27,000 ha of Canadian tree

fruit orchards (Herne 1963; Hagley and

Allen 1988; Pearsall and Walde 1995).

Carabids typically are sampled using

pitfall traps (Spence and Niemelé 1994;

Raworth et al. 1997). Bouchard et al.

(2000), improving on the ramp pitfall trap

oped a trap with plastic ramps connected to

the upper lip of a container which rested on

the terrain surface. In Nova Scotia, a study

to evaluate this modified version of the

ramp trap for diversity studies in orchards

(Rigby and Smith 2002) indicated a similar

' Atlantic Food & Horticulture Research Centre, 32 Main Street, Kentville, NS, B4N 1J5, Canada

* Pacific Agri-Food Research Centre, Summerland, BC, VOH 1Z0, Canada

94 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

capture performance to the conventional

pitfall trap, yet expressed several advan-

tages including minimized fouling of sam-

ples by decomposing plant material and

reduced capture of non-target inverte-

brates. In this study, we used these ramp

traps to document carabid species found on

the orchard floor of organically managed

fruit orchards in the southern Similkameen

valley of British Columbia.

MATERIALS AND METHODS

Ramp traps were placed in six commer-

cial, certified organically managed apple

orchards in the southern Similkameen val-

ley in British Columbia (119.736 °W,

49.169 °N to 119.753 °W, 49.182 °N) in

each of two years (1999-2000). Each trap

consisted of two ramps and one plastic

container with a removable snap-on lid

(Figure 1). The container measured 115

mm in diam and 85 mm in height. Two

rectangular notches (45 mm x 40 mm)

were cut in opposite sides of the container

to hold the ramps in place at an angle < 15°

(after Bouchard et a/. 2000) and to serve as

an entrance into the container. The ramps

were made of 0.75 mm thick transparent

copolyester sheets with the upper surface

textured with Speckle Stone black/grey

aerosol paint (Crown North America Pro-

fessional Products, Vaughan, Ontario,

Canada). Ramps were 300 mm long and

300 mm wide at the lower surface, tapering

to 40 mm at the container entrance. The

22 mm lateral edges were folded up at a

90° angle from the surface of the ramp,

and the upper end had a 20 mm flap folded

down to anchor the ramp to the container.

All six orchards were part of an area-

wide codling moth control program which

used a combination of mating disruption

and sterile insect release to suppress moth

populations (Dyck and Gardiner 1992).

Orchards contained a mixture of apple cul-

tivars (mainly McIntosh, Spartan, Red De-

licious and Golden Delicious) and ranged

in size from 0.5 to 4.4 ha. The orchard

floors consisted of bare soil and/or vegeta-

tion (mainly orchard grass and broad leaf

weeds) and were mowed routinely

throughout the cropping season. In each

orchard three ramp traps were placed be-

neath the tree canopy, 15 to 30 m apart.

Samples were collected in a salt water so-

lution (with a droplet of detergent) which

was replaced when samples were removed,

at 7 - 10 day intervals from 23 April - 19

October 1999, and 19 April - 2 November

2000. Samples were stored in 70% ethanol

until carabid specimens were sorted and

identified to species level using the keys of

Canadian and Alaskan Carabidae devel-

oped by Lindroth (1961-1969b). Voucher

specimens are currently held in the Insect

Reference collection at the Agriculture and

Agri-Food Canada, Atlantic Food & Horti-

culture Research Centre, Kentville, Nova

Scotia.

Figure 1. Ramp pitfall trap used for collection of Carabidae in organic apple orchards.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

RESULTS AND DISCUSSION

In the two years of study 44 carabid

species from 14 genera were identified

(Table 1), of which 13 species (30% of

total) were non-indigenous. Non-

indigenous species represented 74% of the

4299 beetles captured. These results are

similar to those found in previous studies

from Nova Scotia: Pearsall and Walde

(1995) collected 28 species from 13 gen-

era, of which nine species (32%) were non-

indigenous; Smith et al. (2000) reported

more than 40 species from 19 genera col-

lected in orchards with 70% of the total

beetles captured being non-indigenous;

O’Flaherty (2002) collected 55 species of

Carabidae representing 18 genera. In that

study, almost 90% of the total beetles

caught were from the 16 non-indigenous

species (O’Flaherty 2002).

In this survey, carabid diversity ranged

from 11 to 28 species per orchard block

(Figure 2). The most frequently collected

genus was Pterostichus Bonelli, with one

introduced species, P. melanarius (lliger)

accounting for almost 56% of the speci-

mens captured in the two years. The sec-

ond most frequently collected genus was

Harpalus Latreille, which represented 43%

of total captures. Many species (46%)

were represented by fewer than three

specimens each (Table 1). Carabid densi-

ties in apple orchards in southern Ontario

were found to be highest in the late sum-

mer and fall (Holliday and Hagley 1979).

Our data documents similar trends, how-

ever, the majority of carabids collected

were of two species, Harpalus pensylvani-

cus (DeGeer) and P. melanarius (Figure

3).

Published data are sparse regarding

carabid prey species, but it is generally

noted that there is a positive correlation

between the size of beetles and that of prey

attacked (Larochelle 1990; O’Flaherty

2002). Three of the carabid species col-

lected in this study, Amara _ aenea

(DeGeer), Harpalus affinis (Schrank) and

Pterostichus melanarius, have been re-

ported as codling moth predators (Hagley

and Allen 1988; Riddick and Mills 1994),

but the orchards used in this survey had

low codling moth densities (J. Cossentine,

pers. obs.), so it is unlikely that it was a

primary source of food for these carabid

species. However, the generalist predatory

tendencies of carabid beetles make them

beneficial in orchard ecosystems, since

other important pest species serve as food

sources (Larochelle 1990; Sunderland

2002).

The species composition of carabid

beetles within orchards and most ecosys-

tems in North America appears to be

changing with the arrival and successful

establishment of non-indigenous species.

Jarrett and Scudder (2001) list 19 new

British Columbia carabid records and indi-

cate that several of these have been intro-

duced into North America, some with dis-

junct east and/or west coast distributions.

Clearly, both Atlantic and Pacific coast-

lines serve as arrival points for many spe-

cies (Jarrett and Scudder 2001), of which

many are well established (Bousquet and

Larochelle 1993). Within 10 years, it ap-

pears that native Pferostichus coracinus

(Newman), reported by Pearsall and Walde

(1995) as comprising over 40% of ground

beetles in Nova Scotia orchards, has been

displaced by the introduced P. melanarius.

O’Flaherty (2002) failed to collect P.

coracinus, while P. melanarius accounted

for over 45% of beetles captured in that

study. Similarly in Nova Scotia, it appears

that the native Harpalus pensylvanicus 1s

being displaced by H. rufipes, which ac-

counted for a large proportion of the bee-

tles caught by Pearsall and Walde (1995)

and O’Flaherty (2002). Although Prerosti-

chus melanarius is common in British Co-

lumbia (Table 1; Raworth ef al. 1997),

Harpalus rufipes (DeGeer) has not yet

been recorded in this province (Bousquet

and Larochelle 1993). As such, H. pensyl-

vanicus is still the most common represen-

tative of this genus in orchards.

As carabids represent a yet unresolved

biological control resource in Canadian

96 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

The number and percentage of Carabidae captured in ramp traps in six organically managed apple

orchards in British Columbia for 1999 and 2000. Species marked with an asterisk (*) are non-

indigenous.

Rare 1999 2000

P Total % Total %

*4gonum muelleri (Herbst) 45 4.14 65 2.02

*4gonum placidum (Say) ] 0.09 15 0.47

*Amara aenea (DeGeer) 1 0.09 16 0.50

*4Amara apricaria (Paykull) 2 0.18 64 2.00

*Amara aulica (Panzer) — — ] 0.03

Amara avida (Say) 7 0.64 8 O25

Amara californica californica Dejean ~ ~ 4 0.13

Amara cupreolata Putzeys iil 1.01 i 0.22

*4Amara familiaris (Duftschmid) 21 1.93 48 1.49

Amara latior (Kirby) en 1.93 79 2.46

Amara littoralis Mannerheim _ oe ] 0.03

Amara musculis (Say) - - 6 0.19

Amara obesa (Say) - - 5 0.16

Amara carinata (LeConte) ] 0.09 B 0.06

*Anisodactylus binotatus (Fabricius) 23 2.12 64 1.99

Anisodactylus californicus Dejean - - ] 0.03

Anisodactylus harrisii LeConte 5 0.46 1] 0.34

Anisodactylus nigerrimus (Dejean) 4 0.36 84 262

*Bembidion lampros (Herbst) 59 5.43 70 2.18

*Bembidion quadrimaculattum dubitans (LeConte) ] 0.09 - -

Bembidion rupicola (Kirby) ] 0.09 = —

*Carabus granulatus granulatus Linné 22 2,02 40 e253

Carabus taedatus Fabricius ] 0.09 — —

*Harpalus affinis (Schrank) 87 8.00 118 3.67

Harpalus carbonatus LeConte ] 0.09 = _

Harpalus fraternus LeConte ] 0.09 2 0.06

Harpalus herbivagus Say — — ] 0.03

Harpalus nigritarsis C.R. Sahlberg ] 0.09 i) 0.09

Harpalus pensylvanicus (DeGeer) 283 26.03 472 14.69

Harpalus seclusus Casey 33 3.04 47 1.46

Harpalus solitaris Dejean - — ] 0.03

Harpalus somnulentus Dejean = — 6 0.19

Lebia viridis Say ] 0.09 — —

Loricera pilicornis (Fabricius) 2 0.18 5 0.16

Poecilus lucublandus (Say) — - 10 0.31

Pterostichus adstrictus Eschscholtz 2 0.18 ] 0.03

Pterostichus corvinus (Dejean) ] 0.09 — =

*Pterostichus melanarius (Illiger) 446 41.03 1951 60.74

Pterostichus mutus (Say) _ - l 0.03

Scaphinotus marginatus (Fischer von Waldheim) — - ] 0.03

Stenolophus conjunctus (Say) — ~ l 0.03

Stenolophus unicolor Dejean l 0.09 _ —

Syntomus americanus (Dejean) ] 0.09 — =

*Trechus obtusus Erichson 1 0.09 1 0.03

Total number captured 1087 3212

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004 97

Number of Carabid Species

BM i000 G 2000

Organic Orchard Number

Figure 2. Mean number of Carabidae species captured in ramp pitfall traps in each of six or-

ganically managed British Columbia apple orchards in 1999 and 2000.

carabids captured per trap carabids caplured per trap

carabids captured per trap

Harpalus pensylvanicus

(é] lceaciomal a

April 23 May 13 June 10 July 7 Aug 13 Sept 17 Nov 2

sample date

Harpalus affinis

0 :

April 23. May13 June 10 July 7 Aug 13 Sept 17 Nov 2

sample date

Pterostichus melanarius

April 23 May 13 June 10 July 7 Aug 13 Sept 17 Nov 2

sample date

————" 4999 —— - 2000

Figure 3. Phenology of three prominent carabid species as monitored by ramp pitfall traps in

six organically managed apple orchards in British Columbia: Harpalus pensylvanicus (upper

graph), H. affinis (middle graph) and Pterostichus melanarius (lower graph).

98 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

orchards, it would be opportune to better will require further monitoring of carabid

understand what they are consuming in the populations throughout these ecosystems,

orchards, and how best we can augment and continued assessment of their chang-

their consumption of pest species. This ing proportions.

ACKNOWLEDGEMENTS

The authors wish to thank Linda Jen- Cereal Oil Research Centre, Ottawa, On-

sen, Pacific Agri-Food Research Centre, tario for confirmation of species identifica-

Summerland, British Columbia for techni- tions.

cal assistance, and Henri Goulet, Eastern

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100 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 10]

Phenology of emergence from artificial overwintering

Shelters by some predatory arthropods common

in pear orchards of the Pacific Northwest

DAVID R. HORTON!

ABSTRACT

The phenology of emergence from artificial overwintering shelters that had been placed

in pear orchards located near Yakima, Washington, was determined for the green lace-

wing Chrysopa nigricornis Burmeister, the predatory mirid Deraeocoris brevis (Uhler),

and the brown lacewing Hemerobius ovalis Carpenter. Cumulative emergence from

shelters was determined in 2001 and 2002 on both a calendar-date and degree-day basis.

Similar data for a major pear pest, pear psylla, Cacopsylla pyricola (Forster), were also

collected for these same shelters. Pear psylla and H. ovalis emerged earliest, both taxa

completing emergence by early March (120 degree-days accumulated from early Janu-

ary). Deraeocoris brevis emerged beginning in late February and finished emergence

by early April (150 degree-days for 90% emergence). Chrysopa nigricornis emerged

considerably later than the other species, and completed emergence by late May or early

June. Calendar-date emergence is also shown for spiders (Araneae) and Anthocoridae

(Heteroptera), which occurred at lower numbers in the shelters. The anthocorids, Orius

tristicolor White and three species of Anthocoris, emerged from shelters in February and

March, while spiders emerged over a long interval between March and May.

Key Words: overwintering, spring emergence, biological control, pear psylla, green

lacewings, brown lacewings, predatory Heteroptera

INTRODUCTION

Many species of predatory arthropods

overwinter in pear orchards of the Pacific

Northwest (Horton et a/. 2001, 2002), and

it is likely that some of these taxa provide

biological control of orchard pests in

spring. As broad-spectrum insecticides are

used less extensively and selective controls

such as mating disruption are put into

place, pear growers in the Pacific North-

west may benefit from increased levels of

biological control (Knight 1994; Gut and

Brunner 1998). Yet, for many predatory

taxa, much remains unknown about certain

life history characteristics, including dia-

pause, overwintering biology, and post-

diapause development. Here, I describe

phenology of emergence from overwinter-

ing quarters for several predatory species

known to overwinter in orchards (Horton

et al. 2002). Late-winter and early-spring

control of pear pests such as pear psylla,

Cacopsylla pyricola (Forster), 1s important

for season-long management (Westigard

and Zwick 1972), and results reported here

should assist growers in better predicting

when certain predators are likely to be ac-

tive in their orchards.

MATERIALS AND METHODS

Tree bands of corrugated cardboard

were used to provide overwintering shel-

ters for arthropods. Cardboard bands have

been used to monitor a variety of overwin-

tering predatory arthropods, including

Neuroptera (New 1967; Mizell and Schiff-

USDA-ARS, 5230 Konnowac Pass Rd., Wapato, WA, United States 98951

102 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

hauer 1987; Horton et a/. 2002), spiders

(Horton et a/. 2001), and Heteroptera (Fye

1985; Horton et al. 2002), all taxa that

were monitored in the present study. Each

band was 7.6 cm wide and long enough to

completely encircle the trunk of the pear

tree 0.2 to 0.3 m above the orchard floor.

Corrugations in the cardboard were ca. 4 x

5 mm, which is large enough to allow ar-

thropods the size of adult Neuroptera to

colonize the corrugations. Ten trees were

banded in each of 19 and 24 orchards in

October or November of 2000 and 2001,

respectively. Orchards were primarily

‘Bartlett? and ‘D’Anjou’ varieties, of vari-

ous ages. The orchards extended from the

eastern Yakima Valley (Zillah and Parker,

Yakima County, WA) to the western part

of the valley (Yakima, Cowiche, and Tie-

ton, Yakima County, WA). Pest control

practices included a range of management

programs from conventional insecticidal to

organic.

The bands were removed from the field

in the first week of January 2001 and 2002

and placed in white plastic boxes (100 x 40

x 24 cm). The boxes had organdy screen-

ing on the top and four sides to allow air

circulation. A separate container was used

for each orchard. Bands and containers

were then placed in a large shed enclosed

on 3 sides by wire screening, located 15

km southeast of Yakima, WA. The shed

was not heated or lighted.

Containers were checked every 3 or 4

days beginning in early January and ending

in early June of both years. The lid, sides,

and floor of each container were examined

for pear psylla, predatory insects, and spi-

ders. Arthropods were counted and aspi-

rated into vials. Specimens other than

Chrysopidae and Hemerobiidae were dis-

carded after having been counted. The

lacewings were taken to the laboratory for

further examination. Chrysopids were

identified as Chrysopa nigricornis Bur-

meister using the key in Penny ef al.

(2000). A subsample (n = 42) of Hemero-

biidae was examined; all specimens were

identified as Hemerobius ovalis Carpenter

(Kevan and Klimaszewski 1987). Voucher

specimens of C. nigricornis and H. ovalis

are in the collection of the author.

Temperature in the shed was recorded

at hourly intervals using a Hobo data log-

ger (Onset Computer Corporation, Bourne,

MA) placed in one of the containers. In

the first year of the study, a second Hobo

recorder was placed in a pear orchard lo-

cated 500 m south of the shed, to deter-

mine whether temperatures in the shed

were similar to those occurring in the

neighboring orchard. The Hobo unit was

placed in a white, ventilated wooden box

(15 x 30 x 30 cm) at 1.5 m above ground.

Cumulative percent emergence from

shelters was expressed as a function of

calendar-date and as a function of accumu-

lated degree-days. Emergence curves were

developed for the 3 predatory taxa most

abundant in the bands, which were two

lacewings, C. nigricornis and H. ovalis,

and a muirid bug, Deraeocoris brevis

(Uhler). One pest species, pear psylla, was

also monitored. For some less common

taxa (spiders, Anthocoridae), emergence

from bands was summarized for two-week

intervals and presented in tabular form.

“Emergence” used throughout the manu-

script refers to the dates that the arthropods

were aspirated from the walls of the con-

tainer. Certain arthropods (e.g., jumping

spiders [Salticidae]) may have moved in

and out of the corrugations, and for these

taxa it is not clear that “emergence”, as

used here, necessarily reflects what occurs

in the field.

Data from the Hobo recorders were

used to calculate degree-days by means of

a program available on the Oregon State

University web-site (Coop 1999). The

calculations were done using the single

sine curve method and a lower threshold of

5 °C. Accumulations both years began

when the bands were placed in the

screened shed (8 January 2001 and 10

January 2002).

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

103

RESULTS

Temperatures were higher in 2002 than

2001 (Fig. 1). In 2001, when both the

screened shed and the neighboring orchard

were monitored, temperatures were higher

in the shed than in the orchard. Thus, data

presented below expressing emergence as

a function of calendar-date probably show

emergence from bands to have occurred

earlier than that taking place naturally in

the neighboring orchard.

Pear psylla were extremely abundant in

the bands both years (Table 1). Of the

natural enemies, C. nigricornis, D. brevis,

and H. ovalis occurred at the highest densi-

ties. Less common were spiders and An-

thocoridae (Orius tristicolor (White), An-

thocoris spp.). Anthocoris spp. included A.

antevolens White, A. whitei Reuter, and A.

tomentosus Péricart. Species’ identifica-

tions were not made for all samples, so I

combined the three species as Anthocoris

spp.

Pear psylla and H. ovalis began emerg-

ing from bands by early February in both

years of the study (Fig. 2). Psylla had

completed emergence by early March

(2001) and early February (2002); the dif-

ference in calendar dates the two years

reflects the warmer temperatures in 2002

than 2001 (Fig. 1). Hemerobius ovalis had

finished emergence by early March. As

with pear psylla, emergence occurred ear-

lier in 2002 than 2001. Deraeocoris brevis

began appearing in containers in late Feb-

ruary both years and had finished emer-

gence by the middle of March in 2002 and

1000

800

Cumulative degree-days

riperesintt Seek as

early April in 2001 (Fig. 2). Chrysopa

nigricornis was considerably later in emer-

gence than the other two predatory taxa,

and completed emergence by the middle of

May in 2002 and by early June in 2001.

Emergence in 2001 did not begin until

early May; by this time in 2002, C. nigri-

cornis had achieved 50% emergence.

Emergence from shelters was also ex-

pressed as a function of cumulative degree-

days (Fig. 3). Full emergence from shel-

ters by pear psylla required few heat units.

Hemerobius ovalis had completed 90% of

emergence by 73 and 111 cumulative de-

gree-days in 2001 and 2002, respectively.

Curves for D. brevis were very similar the

two years, and this species required about

150 degree-days to complete 90% emer-

gence from shelters (Fig. 3). Chrvsopa

nigricornis began emerging from bands at

about 400 degree-days, and required 600 to

730 degree-days to complete 90% emer-

gence. Fifty percent emergence for C.

nigricornis required 500 and 520 cumula-

tive degree-days in 2001 and 2002, respec-

tively. Curves for C. nigricornis were very

similar in the two years until at the end of

the emergence period, when emergence

from bands in 2001 was slower than in

2002 (Fig. 3).

Spiders emerged over a fairly broad

interval (Table 2), probably because this

taxon comprised a mix of species. The

anthocorids emerged in late February and

early March (Table 2).

1 Feb.

1 Mar.

1 April 1 May 1 June

Figure 1. Accumulated degree-days within shed, 2001 (closed circles) and 2002 (closed trian-

gles), and in an orchard neighboring the shed, 2001 (open circles).

104 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 1.

Cumulative numbers of common arthropods emerging from cardboard bands in Jan-June of

2001 (N = 190) and 2002 (N = 240).

2001 2002

Cacopsylla pyricola (Homoptera: Psyllidae) 4638 4778

Chrysopa nigricornis (Neuroptera: Chrysopidae) 237 163

Deraeocoris brevis (Heteroptera: Miridae) 159 235

Hemerobius ovalis (Neuroptera: Hemerobiidae) 136 11]

Spiders (Araneae) 42 104

Orius tristicolor (Heteroptera: Anthocoridae) 6 69

Anthocoris spp. (Heteroptera: Anthocoridae) 8 66

Pear psylla

100 H. ovalis

C. nigricornis

D. brevis

100 +

Cumulative percent emergence

1 Feb. 1 Mar. 1 April 1 May 1 June

Figure 2. Cumulative emergence from bands in 2001 and 2002 by pear psylla (solid circles),

Hemerobius ovalis (inverted triangles), Deraeocoris brevis (open circles), and Chrysopa nigri-

cornis (triangles) versus calendar date (cf. Table 1). Dotted lines depict 50 and 90% cumulative

emergence.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 105

2001

100 PMmOOCIOO OO Oo. oO G R Q00

<i ce Re Reel

80} & ee

7 O &

a ocd ee eee iaade scnenisetn aes

40) @

| Y ra @ Pear psylta

20 eo YM. evalis

4 CC. nigricornis |

as eee ==

0 AA AAA

0 200 400 600 800 1000

Cumulative percent emergence

0 200 400 600 800 1000

Cumulative degree-days

Figure 3. Cumulative emergence from bands in 2001 and 2002 by pear psylla (solid circles),

Hemerobius ovalis (inverted triangles), Deraeocoris brevis (open circles), and Chrysopa nigri-

cornis (triangles) versus accumulated degree-days (cf. Table 1). Dotted lines depict 50 and

90% cumulative emergence.

Table 2.

Numbers of spiders, Orius tristicolor and Anthocoris spp. (A. antevolens, A. whitei, A. tomen-

tosus) emerging from bands in 2001 and 2002 versus calendar date.

2001 2002

Spiders Spiders Orius tristicolor Anthocoris spp.

1-15 Jan 0 ] 3 l

16-31 Jan 0 10 19 fi

1-15 Feb 0 7 35 16

16-28 Feb 5 7 10 22

1-15 Mar 8 18 2 9

16-31 Mar 8 25 0 7

1-15 Apr 9 23 0 +

16-30 Apr 6 10 0 0

1-15 May 5 3 0 0

16-31 May l 0 0 0

106 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

DISCUSSION

With reduced use of broad-spectrum

insecticides and increased use of selective

controls such as mating disruption or nar-

row-spectrum insecticides, fruit growers in

the Pacific Northwest may experience in-

creased levels of biological control in their

orchards (Westigard et a/. 1968; Knight

1994). Results reported here and else-

where (Horton eft a/. 2001, 2002) indicate

that a large diversity of predatory arthro-

pods may overwinter in pear orchards.

Horton et al. (2001, 2002) described sea-

sonal phenology of autumn entry into over-

wintering shelters by natural enemies in

pear orchards. Practical aims were to tell

growers whether late-season insecticide

applications, if made, would occur while

predatory arthropods were still active in

the orchard. In the present study, I exam-

ined phenology of emergence from over-

wintering quarters. Calendar-day or de-

gree-day models for use in_ predicting

emergence from overwintering sites in

deciduous fruit or nut orchards in North

America have been developed for both pest

(Bergh and Judd 1993) and _ predator

(Felland et al. 1995; Mizell and Schiff-

hauer 1987) species.

Of the four most common taxa that

emerged from the bands, pear psylla was

the most abundant (Table 1). This insect 1s

among the most damaging arthropod pests

of pears in North America and Europe

(Westigard and Zwick 1972; Solomon ef

al. 1989). Pear psylla overwinters in the

adult stage as a distinct morphological

phenotype, the winterform, which began

appearing in pear orchards of the study

area in early September. The species is

active at cool temperatures, and can be

seen moving about on the pear tree in mid-

winter on sunny days. Pear psylla began

emerging from the bands after only mini-

mal accumulation of heat units (Fig. 3).

Egg-laying in the study area commences

by March (Horton 1999).

A green lacewing, C. nigricornis, was

also abundant both years in the bands (see

also Horton et a/. 2002). This green lace-

wing is a common inhabitant of deciduous

fruit and nut orchards (Grasswitz and Burts

1995; Szentkiralyi 2001), apparently as a

generalist predator of soft-bodied insects

such as aphids, mealybugs, and psyllids

(Toschi 1965; Grasswitz and Burts 1995); I

have reared C. nigricornis to the adult

stage on a diet of nymphs and eggs of pear

psylla (DRH, unpublished data). Chrysopa

nigricornis has a facultative diapause con-

trolled by photoperiod, and overwinters as

a third instar within the cocoon (Tauber

and Tauber 1972). The species emerged

from overwintering shelters considerably

later in the season than the other predator

or pest species monitored here, and had not

completed emergence until well into May

both years (Fig. 2). Mizell and Schiff-

hauer (1987) showed that C. nigricornis

emerged from overwintering — shelters

placed in pecan orchards of Georgia begin-

ning in late March and early April, much

later than spiders and a coccinellid beetle

common in those orchards.

The brown lacewing H. ovalis, like pear

psylla, began emerging from bands after

only minimal accumulation of heat units

(Fig. 3). Species of Hemerobiidae often

show activity or development at relatively

cool temperatures (Neuenschwander 1976;

Canard and Volkovich 2001), so their

emergence in late winter is not unexpected.

Biology of Hemerobius species, including

diapause and overwintering, is poorly de-

scribed. Within the Hemerobiidae, all

stages from egg to adult have been re-

corded to overwinter (Canard and Volk-

ovich 2001). In the present study, brown

lacewings emerged from the bands as

adults, and I assume that they overwintered

in this stage. Adults of several

Hemerobius species, including H. ovalis,

have been collected in mid-winter in areas

of the Pacific northwest (Foster 1942;

Kevan and Klimaszewski 1987), which is

additional evidence that this species over-

winters in the adult stage. The role of

brown lacewings in orchards has not been

systematically studied, despite their fairly

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

regular appearance in temperate zone or-

chards (Szentkiralyi 2001). McMullen and

Jong (1967) reported that H. pacificus

Banks preyed upon eggs and nymphs of

pear psylla in Canadian pear orchards,

while Nickel ef al. (1965) stated that H.

angustus Banks provided biological con-

trol of psylla in California pear orchards.

Deraeocoris brevis has a facultative

diapause controlled by photoperiod, over-

wintering in the adult stage (Horton ef al.

1998). This species emerged from bands

beginning in late February or early March,

and had completed emergence by mid- to

late-March. Deraeocoris brevis preys ex-

tensively on soft-bodied arthropods such as

aphids and psyllids (McMullen and Jong

1967; Messing and AliNiazee 1985) and

occupies a variety of habitats including

pear and apple orchards (Horton and Lewis

2000). When pear psylla is at high densi-

ties in pear orchards, this predator may be

among the most abundant of natural ene-

mies in the orchard (Westigard ef al.

1968). McMullen and Jong (1967) stated

that D. brevis is second in importance only

to species of Anthocoris as a predator of

pear psylla in pear orchards of the Pacific

northwest.

Maximal use of natural enemies in or-

107

chards requires improved understanding of

natural enemy biology, including overwin-

tering biology. Horton and Lewis (2000)

described use of natural habitats and or-

chards for overwintering by various spe-

cies of predatory arthropods, while Horton

et al. (2001, 2002) described late-season

phenology of predators entering overwin-

tering shelters. By knowing when preda-

tors emerge from overwintering quarters,

growers would have a better idea about the

potential for biological control early in the

season, a critical time for managing pests

such as pear psylla. Results reported here

suggest that at least one known important

predator of pear psylla, D. brevis, emerged

from shelters early enough in late winter

that it could be active in pear orchards at

the same time that overwintered pear

psylla would be depositing substantial

numbers of eggs (March and April). The

data also suggest, however, that D. brevis

and several other taxa (H. ovalis, O. tristi-

color, Anthocoris spp.) could be active in

Pacific Northwest orchards at the time of

the earliest insecticide sprays. Thus, it

seems possible that these predators could

be exposed to those early-season pest con-

trol practices.

ACKNOWLEDGEMENTS

I thank Deb Broers, Merilee Bayer, and

Dan Hallauer for assistance. Taxonomic

help was provided by Tamera Lewis and

Gene Miliczky. The comments of Rick

Hilton, Alan Knight, and Pete Landolt on

a previous version of this manuscript are

appreciated. This research was partially

supported by the Winter Pear Control

Committee.

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J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

109

Douglas-fir beetle lipid levels in relation

to tree physical characteristics

KEVIN J. DODDS!” and DARRELL W. ROSS!

ABSTRACT

The relationship of Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, brood

adult lipid levels and position of development along infested tree boles was investigated.

In addition, the effects of phloem and bark thickness on brood adult lipid levels were

also tested. There were no significant differences (P > 0.05) in brood adult lipid levels

in relation to bole position, phloem thickness, or bark thickness found in this study.

Numbers of attacks, larval mines, brood adults, and parasitoid cocoons did not differ

significantly by tree bole position. Results from this study suggest Douglas-fir beetle

does not benefit, in the form of increased lipid levels, from oviposition at different bole

positions.

Key Words: Dendroctonus pseudotsugae, lipids, phloem thickness, optimal habitat

INTRODUCTION

Bark beetles are economically impor-

tant insects and knowledge of factors that

affect their flight and dispersal behavior

could be useful for improving existing

management techniques or developing new

ones. Within a population beetles display

varying degrees of flight capabilities from

extended flight periods to those incapable

of flight (Atkins 1966; Jactel 1993). This

variation in flight capability can be related

to a beetle’s physiological state.

Lipids are a source of energy for insect

flight (Canavosa et al. 2001) and have

been correlated with flight capabilities in

bark beetles (Atkins 1966; Slansky and

Haack 1986; Jactel 1993). Atkins (1966)

found that Douglas-fir beetle (DFB), Den-

droctonus pseudotsugae Hopkins, with

high lipid levels were least likely to re-

spond to pheromones and hence disperse,

while beetles with low lipid levels re-

sponded immediately to pheromones.

Bennett and Borden (1971) found that a 90

minute flight was required before DFB

responded to pheromones, suggesting the

need to metabolize lipids before phero-

mone arrestment occurred (Atkins 1969).

Relationships between lipid levels and

responsiveness to host chemicals, phero-

mone arrestment, or dispersal behavior

have been found in other bark beetle spe-

cies as well (Hagen and Atkins 1975; Hed-

den and Billings 1977; Wallin and Raffa

2000). Because of their association with

bark beetle dispersal potential, a better

understanding of factors that influence

lipid levels 1s important for understanding

population movements.

Bark beetle lipid levels are influenced

by temperature (Atkins 1967), attack den-

sity (Atkins 1975; Botterweg 1983; Ander-

brandt et al. 1985), mycangial fungi

(Coppedge eft al. 1995) and phloem thick-

ness (Slansky and Haack 1986). However,

with the exception of Ips calligraphus

(Germar) (Slansky and Haack 1986), it 1s

unknown whether host tree characteristics

affect lipid levels in bark beetle brood

adults. Nutrient levels (N, P, Mg, Fe, Zn)

vary by bole height on Douglas-fir, Pseu-

dotsuga menziesii (Muirb.) Franco, tree

boles and could influence patterns of insect

colonization (Schowalter and Morrell

2002). In several Dendroctonus species,

' Department of Forest Science, Oregon State University, Corvallis, OR 97331

* Current address: Department of Forest Resources, University of Minnesota, Grand Rapids, MN 55744

110 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

initial attacks occur at or near mid-bole

(Miller and Keen 1960; Fargo ef al. 1978;

Safranyik et al. 1992) possibly due to

phloem nutrients at these heights. Conse-

quently, brood developing at mid-bole

could have higher lipid levels than brood

developing elsewhere along the tree bole.

Other factors, such as parasitism or

predation rates, could influence coloniza-

tion behavior. Studies investigating the

relationship between parasitoid density and

tree height have produced mixed results.

Several studies found relationships be-

tween parasitoid density and height on tree

boles (Ryan and Rudinsky 1962; Mills

1986; Wermelinger 2002), while others

have not (Gargiullo and Berisford 1981).

Our objectives were to determine if

DFB brood development position along the

length of tree boles and bark and phloem

thickness affected lipid levels in brood

adults and to determine the influence of

bole position on attack density, larval

mines, brood adults, and parasitoids.

MATERIALS AND METHODS

Tree Sampling. On 27 to 29 April,

2002, prior to the DFB flight period, nine

Douglas-fir trees infested the previous year

were felled and sampled from a small

stand (< 1 ha) of pure Douglas-fir in the

Rock Creek Area (N 46° 34.619’ W 113°

40.067’), 60 km southeast of Missoula,

MT. The sample trees ranged in diameter

from 40.2 to 71.6 cm. An additional six

trees were felled and sampled from one

Douglas-fir stand on the Flathead National

Forest (N 46° 25.316; W 114° 37.995) near

Whitefish, MT on 6 April, 2003. How-

ever, because DFB attacks were only suc-

cessful on small portions of the tree boles,

only two of the six additional trees (41.1

and 53.3 cm diameter breast height) were

suitable for use in this study. Pheromone

baiting live trees prior to DFB flight was

considered, but concerns over initiating

large infestations on federal lands and the

unnatural selection of host trees necessi-

tated avoidance of this method. All sample

trees in this study were naturally selected

and colonized by DFB.

The portion of each tree bole infested

by DFB was distinguished by the presence

of successful egg galleries and brood

adults. Total length of infested tree boles

and dbh were recorded. Infested tree bole

lengths ranged from 6.7 to 14.6 m(X = 9.7

m, SE + 0.8). Bark samples were collected

at three positions along the infested tree

bole: 2 m up from the bottom of the infes-

tation, the mid-point of the infested tree

bole, and 2 m down from the top of the

infestation.

Four bark samples were collected from

each bole position. Bark samples were

taken randomly around the circumference

of each tree. A 100-cm? hole saw attached

to a power drill was used to remove bark

samples from the infested tree. Bark sam-

ples were removed and placed individually

in labeled plastic bags. Samples were

transported to the laboratory on ice and

stored in a freezer at -10 °C until proc-

essed. Phloem thickness was measured on

a subsample of bark samples before and

after freezing. No differences in the aver-

age phloem thicknesses before and after

freezing were found (KJD, unpublished

data).

Bark Analysis. Brood adults were re-

moved from bark samples and placed indi-

vidually in numbered 7 ml glass vials with

caps attached. Numbers of DFB entrance

holes, larval mines, parasitoid cocoons,

and bark and phloem thickness were re-

corded for each bark sample. Bark thick-

ness was measured on four locations

around each bark sample, while phloem

thickness was measured in two locations.

To account for bark thickness variability,

the minimum and maximum thicknesses

on each sample were recorded along with

two random measurements.

Lipid Analysis. Beetles (n = 283 from

2002, 73 from 2003) removed from bark

samples were placed in an oven to dry at

70 °C for 48 h then weighed. To deter-

mine the lipid levels of individual beetles,

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

petroleum ether was used to remove lipids

with methods modified from Langor ef al.

(1990). Briefly, 5 ml of petroleum ether

was added to each vial, the vial was

capped, and then placed in a drying oven at

50 °C for 24 h. Petroleum ether was re-

moved and replaced with fresh solvent

every 24 h for a total of 72 h. After the

extraction was complete, beetles were oven

dried for 48 h and reweighed. To ensure

all lipids were extracted, dried beetles were

again placed in petroleum ether for 24 h,

oven dried for 48 h, and reweighed. Be-

cause there was no change in their ex-

tracted weights, it was assumed all extract-

able lipids were removed from the beetles

during the initial 72-h process. Lipid lev-

els were calculated as percent loss in dry

weight. Beetles that had 0% lipid levels

were assumed dead at the time of sampling

and discarded from the study.

Gender of each DFB brood adult was

determined (Jantz and Johnsey 1964). In

addition, pronotal width of each beetle was

measured using microcalipers and a dis-

secting microscope.

Statistical Analysis. Analyses of vari-

ance (PROC MIXED, SAS 8.0) were con-

[Tt

ducted with trees as blocks and bark and

beetle samples grouped by bole position to

test for differences in bark and phloem

thickness, numbers of entrance holes,

brood adults, parasitoid cocoons, and lar-

val galleries by height. Residual and nor-

mality plots were visually interpreted for

homogenous variances and_ normality.

Where necessary, data were log trans-

formed to meet ANOVA assumptions of

normality or variability. Means were com-

pared and separated using Tukey pairwise

comparisons. Regression analysis was

used to determine if there was a relation-

ship between the average lipid levels and

number of brood adults found in each bark

sample. In addition, relationships between

bark and phloem thickness, and lipid levels

and pronotal widths were analyzed using

analysis of covariance. Analysis of covari-

ance was also used to investigate the rela-

tionship between parasitoid abundance and

bark thickness. Differences in lipid levels

and pronotal width by gender were as-

sessed using ANOVA. All reported means

and confidence limits were backtrans-

formed from data used in the statistical

analyses.

RESULTS

There were no significant differences

between brood adult lipid levels and bole

position (Fx. = 0.75, P = 0.48). Overall

lipid levels ranged from 3.12% to 43.08%

and averaged 21.3 (95% CL = 17.8-25.5),

23.6 (19.5-28.2), and 21.8 (18.0-26.3) for

the bottom, middle, and top position re-

spectively. Less than 26% of beetles from

both sample years had < 15% lipid levels

(Figure 1). The largest number of beetles

from all three bole positions had between

25-35% lipids, while very few had < 5%

lipids (Figure 2). Analysis of covariance

indicated there was no significant relation-

ship between phloem thickness (F2. 29=

0.87, P = 0.43) or bark thickness (F) 29=

0.73, P = 0.49) and lipid levels. Phloem

thickness ranged from 1.5 mm to 4.9 mm,

while bark thickness ranged from 7.5 mm

to 32.6 mm. There were no significant

relationships between pronotal width and

bole position (F2 .»= 2.02, P = 0.16),

phloem thickness (Fz .= 1.89, P = 0.18),

or bark thickness (F>. 29= 0.34, P = 0.72).

Phloem thickness, numbers of entrance

holes, larval mines, brood adults, and para-

sitoid cocoons were not significantly dif-

ferent among the three bole positions

(Table 1). However, bark thickness was

significantly different among the three

heights (F, »= 32.74, P < 0.0001). Bark at

the bottom was thicker than the middle (tz

= 4.95, P = 0.0002) and top (tx) = 8.02, P<

0.0001) of tree boles, while the middle was

also thicker than the top (tx) = 3.07, P =

0.02). There was no significant relation-

ship between lipid levels and number of

brood adults in bark samples (Fj j;05= 1.44,

P = 0.23). Analysis of covariance indi-

cated there was no relationship between

112 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

”

ao 15

6 10

}

0-5 5-10 10-15 15-20 20-25 25-30 30-35 35-40 40-45

Lipid Levels (%)

Figure 1. Frequency distribution of the proportion of Douglas-fir beetle brood adults by lipid

levels (%) in 2002 (n = 283) and 2003 (n = 73).

# of Beetles

0-5 5-10 10-15 15-20 20-25 25-30 30-35 35-40 40-45

Lipid Levels (%)

Figure 2. Frequency distribution of Douglas-fir beetle brood adult lipid levels (%) by bole

position. n= 356.

number of parasitoids and bark thickness 28.2%) than in male (23.0%, CL = 20.1%,

(Fz 2= 0.92, P= 0.42). 26.0%) DFB (F;.322 = 6.88, P = 0.009).

Overall, the gender of brood adults was There was no difference in pronotal width

55% female and 45% male. Average between male and female DFB (Fj,313 =

brood adult lipid levels were significantly 0.16, P= 0.70).

higher in female (25.3%, CL = 22.4%,

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004 113

Table 1.

Mean (95% CL) bark and phloem thickness and Douglas-fir beetle and parasitoid population

parameters from 100-cm” bark samples taken at three bole positions. Means followed by the

same letter are non-significant as determined by Tukey’s pairwise comparisons (a = 0.05).

Eleven trees were sampled, with a total of n = 44 bark samples taken from each of the three

bole position.

Bole Position

Variable Bottom Middle Top P-value

Bark (mm) 16.28 (13.87-18.91)a 13.74 (11.82-16.12)b 12.43 (10.69-14.44)c <.0001

Phloem (mm) 3.49 (3.22-3.82) 3.39 (3.1-3.71) 3.39 (3.1-3.71) 0.54

No. entrance holes _0.73 (0.55-0.92) 0.91 (0.72-1.09) 0.8 (0.62-0.98) 0.40

No. brood adults 3.49 (2.56-4.81) 2.64 (1.95-3.6) 2.77 (2.03-3.78) 0.29

Ne ate 1.36 (1.08-1.7) 1.32 (1.06-1.65) 1.58 (1.27-1.97) 0.41

cocoons

No. larval galleries 24.95 (17.31-32.6)

31.14 (23.49-38.78)

2/36 (19.72-35.01) 0.11

DISCUSSION

Intraspecific competition has been cor-

related with lipid levels in DFB and other

bark beetle species, (Atkins 1975; Botter-

weg 1983; Anderbrant et a/. 1985), and

must be considered when evaluating fac-

tors that influence brood adult lipid levels.

Because entrance holes, larval mines, and

brood adult densities were equal at the

three bole positions, it was assumed devel-

oping brood encountered similar intras-

pecific competition levels at each position.

Therefore, intraspecific competition should

not have influenced lipid levels in this

study.

Lipid level was not influenced by bole

position or phloem thickness in this study.

However, unmeasured factors such as

phloem quality (e.g., nutrient level), gut

flora, genetics, or length of feeding could

also influence lipid levels. Ayres et al.

(2000) found a positive relationship be-

tween Dendroctonus frontalis

Zimmermann size and phloem nitrogen

levels of infested trees, demonstrating that

phloem qualitative characters determine

fitness attributes of phloem-feeding in-

sects. Phloem nutritional levels at the three

bole positions were not sampled in this

study because sampled trees were already

colonized and extensively fed upon by

bark beetle brood and associated insects

(e.g., Cerambycidae and Buprestidae) at

the time of sampling.

There was no relationship between bark

thickness and lipid content of DFB. Bark

thickness imparts some level of insulation

on host tree phloem (Graham 1924; Beal

1934; Powell 1967) and influences bark

beetle brood survival during cold periods

(Miller and Keen 1960). Consequently,

bark thickness may have influenced lipid

levels in this study, but differences may

have been undetected due to the sampling

procedure. Bark samples were not parti-

tioned by cardinal direction, thus aspect-

related differences in lipid levels could not

be analyzed.

Female brood adults had higher lipid

levels than males in sample trees, while

pronotal widths were equal between the

sexes. In Dendroctonus species, females

locate and initiate colonization of host

trees. This supports the hypothesis that

higher energy levels benefit dispersing

females that must locate, colonize, and

release aggregation pheromones that attract

conspecifics to overwhelm host tree de-

fenses. Similarly, Anderbrant ef a/. (1985)

114 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

found higher lipid levels in male /ps typog-

raphus (L.) and attributed this to males

being the colonizing sex, and therefore

benefiting from increased energy reserves.

Atkins (1966) determined that DFB

adults with lipid levels of less than 10%

were unlikely to fly, those with 11-20%

lipid content can fly and respond to phero-

mones, and brood adults with over 20%

lipid content disperse but are less likely to

respond to pheromones. In the current

study, the majority of beetles from both

sample years had > 20% lipids (Figure 1).

Based on Atkins (1966) data for potential

to disperse, 67.7% of beetles sampled in

this study, regardless of the bole position

where they developed, would be capable of

long distance dispersal.

There were no differences between

parasitoid densities at each bole position.

Although bark was significantly thinner at

the upper bole position, an attribute com-

monly associated with higher parasitism

levels, there was not a higher level of para-

sitoid abundance found there. Likely, para-

sitoids are exploiting thin bark portions or

bark crevices at all positions.

Bark beetles colonizing host trees are

affected by natural predators (Reeve 1997;

Aukema and Raffa 2002), competitors

(Schroeder and Weslien 1994; Dodds et al.

2001), and host tree defenses (Raffa and

Berryman 1983). In addition to minimiz-

ing interactions with these mortality fac-

tors, bark beetles must also locate areas

that are suitable for brood development

and reproductive success. If lipid levels

are viewed as a relative fitness measure,

there seems to be no benefit to oviposition

on different bole positions for developing

DFB brood. Consequently, it is unlikely

that the colonization behavior of attacking

the mid-bole first, is a fitness response to

seeking out and exploiting optimal habitat

for developing brood. While no relation-

ship between lipids and bole position were

found, other factors (e.g., avoidance of

predators or host tree defenses) might

make oviposition at the mid-bole benefi-

cial.

Results from this study suggest DFB

brood adult lipid levels are not influenced

by tree phloem or bark thickness. How-

ever, due to low DFB populations in the

study area, the number of infested trees

available to sample was lower than antici-

pated. Consequently, several of the re-

sponse variables measured had wide 95%

CL ranges that may have been smaller had

more trees been available to sample. If the

number of sample trees had been in-

creased, differences in lipid levels between

the three bole positions may have been

detected.

Beetles emerging from different host

trees within or between forest stands could

explain the population level variations in

brood adult lipid levels and subsequent

flight behaviors found in wild populations.

Further studies into the direct relationship

of phloem characteristics and lipid levels

may help explain landscape level dispersal

behaviors of DFB and mortality patterns

attributed to this beetle.

ACKNOWLEDGEMENTS

The authors would like to thank Ken

Gibson (USDA Forest Service, Forest

Health Protection, Missoula, MT) and Ed

Lieser (USDA Forest Service, Flathead

National Forest, Tally Lake Ranger Dis-

trict) for help locating Douglas-fir beetle

infested trees. Mike Armstrong, Missoula,

MT generously allowed access to his land

and cutting of infested trees. Rick Kelsey

(USDA Forest Service, Pacific Northwest

Research Station) provided access to lab

equipment. Laétitia Plewinski provided lab

assistance. Kimberly F. Wallin (Oregon

State University) provided comments on

an earlier draft of this work.

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521-527.

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

Evaluation of two repellent semiochemicals for disruption of

attack by the mountain pine beetle, Dendroctonus

ponderosae Hopkins (Coleoptera: Scolytidae)

JOHN H. BORDEN’”, DEEPA S. PURESWARAN’”

and LISA M. POIRIER‘

ABSTRACT

When released from attractant-baited multiple-funnel traps, 3-methyl-2-cyclohexen-1-

one (MCH) reduced catches of male and female mountain pine beetles, Dendroctonus

ponderosae Hopkins, by 67.4% and 71.8%, respectively. 2-Phenyl ethanol reduced the

respective catches by 96.6% and 95.1%, but only verbenone and all three compounds

together reduced catches to levels no different from those in unbaited control traps. In

another experiment, all three binary combinations of the above compounds, plus the

ternary combination, reduced catches of both sexes by >96%. In comparable tree protec-

tion experiments near Princeton BC, MCH and 2-pheny! ethanol alone and together

significantly reduced the percentages of pheromone-baited lodgepole pines that were

attacked by 16.0%, 33.3% and 40.0%, respectively, but verbenone alone totally pro-

tected baited trees, and many trees within 5 m of them, from attack. In identical experi-

ments near Prince George BC, where mountain pine beetle populations were much

higher, adding MCH, 2-phenyl ethanol or both together to verbenone did not cause at-

tack to be reduced significantly beyond that achieved by verbenone alone. Our results

confirm that 2-phenyl ethanol 1s an antiaggregation pheromone for the mountain pine

beetle, and that MCH 1s an interspecific synomone. However, because neither was as

effective as verbenone in protecting pheromone-baited trees from attack, and adding

either or both to verbenone did not improve protection, neither compound warrants fur-

ther consideration as a potential tool for operational disruption of attack.

Key Words: Dendroctonus ponderosae, semiochemicals, pheromones, verbenone, 2-

phenyl ethanol, 3-methyl-2-cyclohexen-1-one, attack disruption

INTRODUCTION

Although the antiaggregation phero-

mone verbenone has long been known to

disrupt attack by the mountain pine beetle

(MPB), Dendroctonus ponderosae Hop-

kins (Amman ef a/. 1989; Lindgren et al.

1989a), its efficacy has been inconsistent

between years, target species of trees, and

geographic areas (Bentz et al. 1989; Lister

et al. 1990; Gibson et al. 1991; Shea et al.

1992). Part of the reason for variable effi-

cacy may be that verbenone is transformed

to the inactive compound chrysanthenone

when exposed to ultraviolet radiation

(Kostyk et al. 1993). Adding repellent non-

host volatiles from angiosperm tree bark to

verbenone has been shown to increase the

efficacy of protecting lodgepole pines,

Pinus contorta var. latifolia Engelmann,

from attack (Huber and Borden 2001), and

combining a seven-component nonhost

'Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby BC V5A

1S6

* Current address: Phero Tech Inc., 7572 Progress Way, Delta BC V4G 1E9

* Current address: Department of Biological Sciences, Dartmouth College, Hanover NH 03755 USA

“Ecosystem Science and Management, University of Northern BC, 3333 University Way, Prince George

BC V2N 4Z9

118 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

volatile blend with an increased release

rate of verbenone has raised the efficacy

even higher (Borden ef al. 2003). How-

ever, at an effective 10 x 10 m spacing, the

latter treatment would cost $1,250 per ha,

excluding labor, limiting its potential use.

One means of reducing the cost would

be to replace the repellent nonhost volatile

blend with cheaper materials. Two such

semiochemicals are the antiaggregation

pheromone 2-phenyl ethanol (Pureswaran

et al. 2000) and 3-methyl-2-cyclohexen-1-

one (MCH). MCH is an antiaggregation

pheromone of Douglas-fir and spruce bee-

tles, Dendroctonus pseudotsugae Hopkins

and D. rufipennis (Kirby), respectively

(Rudinsky ef a/. 1972; Lindgren ef al.

1989b) that was recently shown to be a

repellent synomone for the mountain pine

beetle (Pureswaran and Borden 2004). Our

objectives were to confirm the bioactivity

of 2-phenyl ethanol and MCH, and to de-

termine in trapping and tree protection

experiments whether they are potential

adjuvants that could increase the efficacy

of verbenone.

MATERIALS AND METHODS

Two randomized complete block, 12-

replicate, field trapping experiments (Exp.

1 and 2) were set up on 31 July and 13

August 2002, respectively, near the East

Gate of Manning Park BC (49° 19' N, 120°

35' W). Tree protection experiments (Exp.

3A and 4A) with treatments identical to

those in the trapping experiments were set

up on 5-7 July 2002 in the valley of Whip-

saw Creek near Princeton BC (49° 9' N,

120° 41' W), and two additional identical

experiments (Exp. 3B and 4B) were set up

on 24-27 July 2002 on the 1400 Road

south of Prince George BC (53° 21' N,

123° 10' W).

For trapping experiments, 12-unit mul-

tiple-funnel traps were deployed at least 15

m apart along logging roads that passed

near infested stands. For the tree protection

experiments, lodgepole pines with a mini-

mum diameter at breast height (dbh = 1.3

m) of 20 cm were selected at least 25 m

apart in rows at least 50 m apart through

cut blocks designated for harvest in the fall

of 2002.

Treatments (Tables 1, 2) in Exp. 1, 3A

and 3B were an unbaited trap or tree

(negative control), and an attractive bait

alone (positive control) or with MCH, 2-

phenyl ethanol, verbenone, or all three

together. In Exp. 2, 4A and 4B, the control

treatments were the same, but the three

disruptants were deployed in all three pos-

sible binary blends and the ternary blend.

All semiochemicals and release devices

were purchased from Phero Tech Inc.,

Delta BC. The attractive trap bait consisted

of the host kairomone myrcene released

from a 20 mL polyethylene bottle at 95

mg/24 h, determined at 23 °C, and the ag-

gregation pheromones 82% _ (-)-trans-

verbenol and (+)-exo-brevicomin respec-

tively released from bubble caps and poly-

urethane flexlures at 1.2 and 0.3 mg/24 h,

determined at 20 °C. The attractive tree

bait was identical to the trap bait, but with

myrcene deleted (Borden ef al. 1993).

MCH, 2-phenyl ethanol and 80% (-)-

verbenone were released from bubble caps

at 4.0, 4.2 and 1.8 mg/24 h, determined at

20, 25, and 20 °C, respectively. Devices

were hung in the central funnel of traps

and affixed to the north face of trees at

maximum reach from the ground. The dbh

of all baited trees was measured, and var-

ied among experiments (mean + SE) as

follows: 30.9 + 1.3 cm to 35.1 + 1.2 cm in

Exp. 3A and 4A near Princeton, and 23.0 +

0.5 cm to 25.3 + 0.9 cm in Exp. 3B and 4B

near Prince George.

Captured beetles in Exp. 1 and 2 were

collected on 13 and 26 August, respec-

tively. Beetles were held at ca. -5 °C in

plastic bags until sexed and counted.

Tree protection experiments were

evaluated on 25-27 September (Exp. 3B

and 4B) and 3-4 October (Exp. 3A and

4A). The attack density was counted at eye

level in two 20 x 40 cm panels on the east

and west faces of baited trees and all trees

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

119

Table 1.

Effect of MCH, 2 phenyl ethanol and verbenone alone or in binary or ternary combinations, on

catches of mountain pine beetles in attractant-baited multiple-funnel traps. Eastgate Road near

Manning Park, B.C., 31 July — 13 August 2002 for Experiment 1 and 13 — 26 August for Ex-

periment 2.

Mean number of beetles captured (SE)

Exp. No. Treatment’ INORG (9S) Gace ee

Males Females

] MPB bait 12 137.8+47.4a 86.5+ 38.8 a

Bait + MCH 12 449+8.9b 24.4+8.2b

Bait + 2 PE 12 4.7+1.1¢ 4.341.2c

Bait + V 12 3.54 1.2 cd 2.3215 ed

Bait + V + MCH + 2PE 12 1.8+0.5 cd 11+0.8d

Unbaited 12 0.8+0.4d 0.8+0.3d

2 MPB bait 12 76.1429.8a 41.3+16.0a

Bait + MCH + 2PE 10 1.7+0.7b 1.6+0.7b

Bait + V + MCH 12 222 15D 1.1+40.6b

Bait + V + 2PE 12 0520.25 0.2+0.2b

Bait + V +MCH + 2PE 12 0.4+0.2b 0.6+0.2b

Unbaited 12 0.1+0.1b 0.3+0.1b

Treatments as follows: MPB bait = mountain pine beetle bait including trans-verbenol, exo-

brevicomin and myrcene; MCH= 3-methyl-2-cyclohexen-l-one; 2PE= 2-phenyl ethanol;

V=verbonene.

*Means followed by the same letter are not significantly different, REGW test, P<0.05

ANOVA results: Exp. 1., males, F=53.87, df=5,66, P<0.0001; Exp. 1, females, F=34.89,

df=5,66, P<0.0001; Exp. 2, males, F=14.45, df=16,52, P<0.0001; Exp. 2, females, F=9.84,

df=16,52, P<0.0001.

with at least five attacks in the total 0.16

m’ area (31.25/m’) were classed as mass-

attacked. All surrounding lodgepole pines

at least 17.5 cm dbh within 5 m of baited

trees were evaluated as unattacked, at-

tacked, or mass-attacked, the latter being

determined qualitatively by visual estima-

tion of attack density and copious amounts

of frass in bark crevices and around the

root collar.

Data for numbers of beetles captured

and attack density on baited trees were log-

transformed and analyzed by ANOVA and

the REGW test (Day and Quinn 1989).

Data on proportions of baited and sur-

rounding trees that were mass-attacked

were analyzed by chi-square tests for com-

parison between multiple proportions

(Jones 1984). In all cases a = 0.05.

RESULTS

In the first trapping experiment (Exp.

1), MCH, 2-phenyl ethanol and verbenone

reduced the catches of male and female

mountain pine beetles in attractant-baited

traps by 67.4%, 71.8% and 96.6%, and

95.1%, and 97.5% and 97.3%, respec-

tively, relative to catches in baited control

traps (Table 1). 2-Phenyl ethanol reduced

catches to levels no different from those

achieved by verbenone (both sexes) or the

ternary blend (males only), but only the

latter two treatments resulted in catches not

significantly different from those in un-

baited control traps. In Exp. 2, all binary

120 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Table 2.

Effect of treatment with MCH, 2-phenyl ethanol and verbenone alone, or in binary or ternary

combinations, on ranked percentages of pheromone-baited lodgepole pines that were mass-

attacked, and on the pooled percentages of all surrounding trees > 17.5 cm dbh within 5 m of

the baited tree that were mass-attacked.

Bey io: | | Percent Surrounding trees

(roses) Location Treatment baited trees we Percent

mass-attacked mass-attacked”

3A (25) Princeton MPB bait 100.00 a 103 15.5 ab

Bait + MCH 84.0 b 119 23.5a

Bait + 2PE 66.7 b 104 4.8b

Bait +V + MCH + 2PE 0.0c 29, 0.0 c

Unbaited 0.0c 100 0.0c

Bait + V 0.0c 117 0.0c

3B(20) ‘Prince George MPB bait 95.0 a 69 47.8 ab

Bait + MCH 80.0 ab 83 31.3 ab

Bait + 2PE 75.0 abc 62 24.2b

Unbaited 40.0 be 65 49.2a

Bait +V + MCH + 2PE 40.0 be 75 18.7b

Bait + V 35.0¢ 70 27.1 ab

4A (20) Princeton MPB bait 100.0 a 96 26.0 a

Bait + MCH + 2PE 60.0 b 93 IS5.la

Bait + V + MCH 53°C 87 1.1 b

Bait + V + 2PE 0.0 c 89 0.0 b

Unbaited 0.0c 103 0.0 b

Bait + V + MCH + 2PE 0.0c 105 0.0b

4B (17) _ Prince George MPB bait 94.1 a a2 44.2a

Bait + V + MCH + 2PE 47.1b 47 25:5 ab

Bait + V + 2PE 35.3 b 61 23.0 ab

Unbaited 29.4b 67 17.9b

Bait + MCH + 2PE 2aa'D 52 36.5 ab

Bait + V +MCH 17.6b 51 25.5 ab

' Treatments as in Table 1, Footnote 1, except that myrcene is not present in MPB bait.

* Percents within a column and experiment followed the same letter are not significantly differ-

ent, chi-square test for multiple proportions, P<0.05.

combinations and the ternary combination

of disruptants reduced catches by more

than 96%, and in all cases catches in traps

with disruptive treatments were no greater

than in unbaited control traps.

In the first tree protection experiment

near Princeton (Exp. 3A), all pheromone-

baited control trees were mass-attacked

(Table 2). MCH and 2-phenyl ethanol

alone reduced the proportion of baited

trees that were mass-attacked by 16.0%

and 33.3%, respectively, but verbenone

and the ternary blend completely protected

pheromone-baited trees and all trees within

5 m of them from attack. In Exp. 3B near

Prince George, only verbenone and the

ternary blend significantly reduced the

percentage of baited trees that were mass-

attacked, and the lowest percentages of

surrounding trees that were mass-attacked

occurred in the 2-phenyl ethanol and ter-

nary blend treatments.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

In the second tree protection experi-

ment near Princeton (Exp. 4A), the binary

combination of MCH and 2-phenyl ethanol

reduced the percentage of baited trees that

were mass-attacked by 40%, but did not

cause a reduction in the proportion of sur-

rounding trees that were mass-attacked

(Table 2). All treatments containing verbe-

none reduced attack to zero or to a level

not significantly different from zero. In

Exp. 4B near Prince George, all treatments

significantly and equally reduced the per-

centage of baited trees that were mass-

attacked, but no treatment had a significant

effect on attack on surrounding trees.

In all cases except Exp. 3B (Bait + V +

MCH + 2 PE), disruptant treatments in-

cluding verbenone caused a reduction in

attack density on mass-attacked trees rela-

tive to the MPB bait alone, but in the ab-

sence of verbenone, only MCH + 2-pheny]

ethanol in Exp. 4B caused a similar reduc-

tion (Table 3).

Table 3.

Effect of treatment with MCH, 2-pheny] ethanol and verbenone alone, or in binary or ternary

combinations, on ranked densities of attack by the mountain pine beetle on pheromone-baited

lodgepole pines.

Beaune, | No. pcan attack density/

(fo repo) Location Treatment attacked m°+SEon attacked

trees trees

3A (25) Princeton MPB bait 25 125.5+10.la

Bait + 2PE 16 112.5413.8a

Bait + MCH 23 108.14+7.6a

Bait + V +MCH + 2PE 3 6.3+0.0b

Bait + V 0 no attack

Unbaited 0 no attack

3B (20) Prince George Bait + MCH 15 105.4+10.5a

MPB bait 19 91.44 8.5 ab

Bait + 2PE 14 77.3 + 10.4 ab

Unbaited 10 62.5 + 13.8 be

Bait + V + MCH + 2PE 8 60.9 + 7.6 be

Bait + V 13 52.9+10.2¢

4A (20) Princeton MPB bait 20 129.1+84a

Bait + MCH + 2PE 14 98.74 148a

Bait + V + MCH 6 25.04 11.9b

Bait + V+ 2PE 5 8.8+4.3b

Bait + V + MCH + 2PE 6 8.3+3.5b

Unbaited l no attack

4B (17) Prince George MPB bait hes 116.349.1a

Bait + V +MCH + 2PE 1) 64.2 + 40.1 b

Bait + V + 2PE 9 58.3411.3b

Unbaited 9 43.8+10.8b

Bait + MCH + 2PE 12 40.6 + 13.9b

Bait + V +MCH fi 40.2 + 14.8 b

' Treatments as in Table 1, Footnote 1, except that myrcene was not present in MPB baits.

* Percents within a column and experiment followed the same letter are not significantly differ-

ent, chi-square test for multiple proportions, P<0.05.

122 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

DISCUSSION

Our results confirm the bioactivity of 2-

phenyl ethanol as an antiaggregation

pheromone of the mountain pine beetle

(Pureswaran et a/. 2000), and MCH as a

repellant synomone (Pureswaran and Bor-

den 2004).

Unlike MCH, 2-phenyl ethanol ap-

peared to have some potential as a pest

management tool. MCH caused only mar-

ginal reductions in trap catches, and af-

forded little protection of trees. In contrast,

2-phenyl ethanol caused large reductions

in trap catches and greater protection of

pheromone-baited and surrounding trees.

In Exp. 1, 2, 3A and 3B in the southern

part of the province, verbenone was so

effective alone that there was no opportu-

nity to observe any potential interaction

between MCH, 2-pheny! ethanol and ver-

benone. However, near Prince George,

where beetle pressure was much higher

than near Princeton, adding MCH, 2-

phenyl ethanol or both together to verbe-

none did not cause any greater protection

of pheromone-baited or surrounding trees

than was achieved by verbenone alone. In

a similar experiment nonhost volatiles

added to verbenone resulted in substan-

tially greater protection of baited and sur-

rounding trees than was found with verbe-

none alone (Huber and Borden 2001).

However, in a small plot experiment the

same nonhost volatile blend caused a

greater reduction of attack than verbenone

alone when added to high-dose verbenone

pouches, but not when added to the same

low-dose bubble caps used in our experi-

ments (Borden et a/. 2003).

Our results show that when tested

alone, 2-phenyl ethanol was more effective

than MCH in reducing catches in attrac-

tant-baited traps (Table 1), as well as the

percentage of baited and surrounding trees

that were mass-attacked (Table 2, Exp.

3A). However, neither MCH nor 2-phenyl

ethanol alone reduced the attack density of

trees that were mass-attacked (Table 3),

and there was no apparent additive or syn-

ergistic effect of combining the two com-

pounds or of adding them alone or together

to verbenone to protect trees from attack.

Therefore, we conclude that neither com-

pound has compelling potential for use as

an adjuvant to verbenone in operational

attack disruption programs.

ACKNOWLEDGEMENTS

We thank L.J. Chong, P. Dodds and M.

Poirier for assistance and Weyerhaeuser

Canada Ltd. and Canadian Forest Products

Ltd. for access to field sites. This research

was supported by the Natural Sciences and

Engineering Research Council, BC For-

estry Innovation Investment and the fol-

lowing industrial sponsors: Abitibi Con-

solidated Inc., B.C. Hydro and Power Au-

thority, Bugbusters Pest Management Ltd.,

Canadian Forest Products Ltd., Gorman

Bros. Ltd., International Forest Products

Ltd., Lignum Ltd., Manning Diversified

Forest Products Ltd., Millar-Western For-

est Products Ltd., Phero Tech Inc., River-

side Forest Products Ltd., Slocan Forest

Products Ltd., Tembec Forest Industries

Ltd., TimberWest Forest Ltd., Tolko In-

dustries Ltd., Weldwood of Canada Ltd.,

West Fraser Mills Ltd., Western Forest

Products Ltd., and Weyerhaeuser Canada

Ltd.

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60-64.

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124 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

125

Heteroptera (Hemiptera: Prosorrhyncha) New to Canada.

Part 2

G.G.E. SCUDDER’

ABSTRACT

The occurrence of an additional six species of true bugs newly recognized in Canada 1s

documented. New US state records are given for two pentatomid species, and a key to

the species of Neottiglossa Kirby in Canada is included.

INTRODUCTION

In a previous paper (Scudder 2000), 34

species of true bugs newly recognized in

Canada was documented. At that time, it

was noted that additional species would be

published in Part 2, when all determina-

tions had been confirmed.

In the intervening period, additional

species have been included in publications

by Schuh (2001), Schwartz and Scudder

(2001, 2003) and Paiero et al. (2004).

I now report an additional six species

new to Canada.

Museum abbreviations used in the text

are as follows:

APM: Alberta Provincial Museum,

Edmonton, AB.

CNC: Canadian National Collection of

Insects, Agriculture and Agri-Food Can-

ada, Ottawa, ON.

LM: Lyman Entomological Museum,

Macdonald College, McGill University,

Ste.-Anne-de-Bellevue, QC.

PFC: Pacific Forestry Centre, Natural

Resources Canada, Victoria, BC.

UA: Strickland Museum, University of

Alberta, Edmonton, AB.

UBC: Spencer Entomological Museum,

Department of Zoology, University of Brit-

ish Columbia, Vancouver, B.C.

SPECIES NEW TO CANADA

Family CYDNIDAE

Amnestus basidentatus Froeschner

QC: 23 29, Aylmer, lumiére, Boisé

décidu., 29.v.1989 (L. LeSage) [CNC].

This species has been swept from grass,

and occurs from New York south to Flor-

ida and Cuba, and west to Missouri and

Texas (Froeschner 1960). A key to sepa-

rate A. basidentatus from the other three

species of Amnestus Dallas that occur in

Canada (Maw et al. 2000) is provided by

McPherson (1982). A. basidentatus has

four marginal pegs on each juga, and the

male has a characteristic anterior subbasal

tooth on the front tibia, giving this segment

a notched appearance on its inner surface.

The ventral subapical spine on the hind

femur of the male is also shorter than the

width of the femur, while in the female, the

last abdominal sternum lacks a flattened

glabrous area.

Family MIRIDAE

Pinophylus carneolus (Knight)

SK: 14, Nipawin, Jack pine, 7.vi.1968

(FIS 605) [CNC].

The genus Pinophylus Schwartz &

Schuh was described by Schwartz and

Schuh (1999) with three contained species,

one of which P. ro/fsi (Knight), was re-

ported from Alberta, British Columbia and

Yukon, and south to Oregon and Colorado.

Pinophylus carneolus was reported from

District of Columbia, Maryland, North

Carolina, Pennsylvania, Virginia, West

' Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4

126 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Virginia and Wisconsin, and like P. rolfsi

is strongly sexually dimorphic. P. carneo-

lus is distinguished from P. rolfsi by the

slightly reddish brown coloration, and the

form of the male genitalia in which the

vesica 1S more strongly curved than in P.

rolfsi. P. carneolus is reported to breed on

Virginia pine, Pinus virginiana Mill. in the

United States (Knight 1927; Schwartz and

Schuh 1999).

Family PENTATOMIDAE

Neottiglossa sulcifrons Stal

SK: 19, Indian Head, Aspen Grove,

3.vill. 1939 (C.R. Douglas) [CNC].

Four species of the genus Neottiglossa

Kirby are now known from Canada. Two

of these, N. trilineata (Kirby) and N. un-

data (Say), occur across Canada from

Yukon to Newfoundland, while N. tumidi-

frons Downes 1s confined to British Co-

lumbia in Canada (Maw et al. 2000). The

following key modified from that in Rider

(1989), will separate the species of Neot-

tiglossa now known from Canada.

1. Coxae pale yellow; evaporative sur-

face on pterothorax ventrally pale yellow

to brown-grey with contrasting black punc-

-Coxae fuscous to black; evaporative

surfaces on pterothorax ventrally black

with concolorous punctures ..............:ce 3

2. Dorsal surface of head and propleura

mostly black with concolorous punctures

etree te ae Oar strilineata (Kirby)

-Dorsal surface of head and propleura

with large areas pale yellow to brown with

black puncture... sundata (Say)

3. Trochanters dark fuscous; scutellum

lacking pale median line ......su/cifrons Stal

-Trochanters pale; scutellum usually

with pale median line. tumidifrons Downes

N. sulcifrons is usually collected in

grassy habitats (McPherson 1982) and is

recorded through much of the eastern and

central Untied States, south to Georgia,

Texas, New Mexico and _é Arizona.

Froeschner (1988) and Rider (1989) sum-

marize the records for the US states. To

these can be added the following new state

records.

COLORADO: 19, Boulder, Flagstaff

Cn., 5800' (1705 m), 8.vili. 1961 (J.R.

Stainer); 14 19, id, 11.vi.1961; 19, Boul-

der, 12.vi.1961 (B.H. Poole); 29, Mt. Ev-

ans, 9800' (2987 m), Doolittle Ranch,

10.viii. 1961 (B.H. Poole); 14, Nederland,

Science Lodge, 9500' (2896 m), 1.v11.1961

(J.R. Stainer); 14, id, 6.vii.1961; 19, id,

9000' (2743 m), 29.vii.1961; 39, Neder-

land, Caribou, 8700' (2652 m), 7.viil. 1961

(J.R. Stainer), OKLAHOMA: 19, Texoma

Lk., 15.vu1.1954 (J.G. Chillcott). SOUTH

CAROLINA: 19, Aiken, 24.vili. 1957

(W.R. Richards); 19, Montmorenci,

23.v1.1957 (W.R.M. Mason) [CNC].

Little is known about the life history

and habits of N. trilineata (McPherson

1982). It is recorded from Alaska (Scudder

1997) (13, Fairbanks, 16.vi.1952 (J.H.

Hartley) [CNC]) and south in the United

States to California, Colorado, Wyoming

and Nebraska (Froeschner 1988; Rider

1989).

N. tumidifrons is a Cordilleran species

recorded from California, Oregon and

Washington, in addition to British Colum-

bia. It occurs in grassy habitats, and in

British Columbia is confined to southeast-

ern Vancouver Island, and the dry southern

interior of the province. N. undata 1s much

more widely distributed, occurring in

grassy habitats from Alaska to California

in the west, and from Newfoundland south

to North Carolina in the east (McPherson

1982).

The fifth species in North America, N.

cavifrons Stal, occurs from Virginia south

to Georgia and South Carolina (New Re-

cord: 19, SC, Montmorenci, 23.vi.1957

(W.R.M. Mason) [CNC)}) in the east. There

are records from Arizona, California, Ore-

gon, Texas and Utah in the west

(Froeschner 1988; Rider 1989) , but the

early reports of this species from British

Columbia (Stoner 1926; Downes 1927) are

in error, as these records refer to N. tumidi-

frons (Downes 1935).

Trichopepla grossa Van Duzee

BC: 14, Osoyoos IRI, 'Brights Winery’,

Purshia assoc., BGxhl AN, Pitfall trap

V2-4, 2.vi.-7.vii.1994 (G.G.E. Scudder)

[UBC]; 19, Fairview, White Lake, Big

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

sage assoc., BGxhl SWm, 7.vui.1996

(G.G.E. Scudder) [UBC].

T. grossa is a Cordilleran species, pre-

viously recorded from California, Colo-

rado, Idaho, Oregon and South Dakota

(McDonald 1976). Four other species of

Trichopepla Stal are recorded from Canada

(Maw et al. 2000), and 7. grossa is most

similar to 7. aurora Van Duzee, which in

Canada is also confined to British Colum-

bia. McDonald (1976) gives a key to sepa-

rate the species. 7. grossa has the abdomi-

nal connexiva rather uniform pale brown

or yellowish marginally, the scutellum has

a pale yellow tip, and the base of the

pronotum and coria are concolorous with

rest of the dorsal surface. In contrast, T.

aurora has an alternating pattern of black

and pale brown on the abdominal connex-

iva, the tip of the scutellum is concolour-

ous and not pale, while the base of the

pronotum and the coria are usually clearly

roseus.

Family THY REOCORIDAE

Galgupha ovalis Hussey

In Canada, first reported from Alberta

and British Columbia in Maw et al. (2000),

without data. Now also known from Sas-

katchewan. Specimens examined: 57¢

829.

AB: Elkwater, 15.vi.1955 (George E.

Ball) [UA]; Gull Lake, 8.vi.1929,

14.v1.1929, 22.vi1.1929 (E.H. Strickland)

[UA], previously determined as G. nitidu-

loides (Wolff); Medicine Hat [LM]; CFB

Suffield, NWA, 26.v.1994, 16-28.v1.1994,

16-29.v1.1994, 28.v1.1994, 28.vii.-16.vil.

1994, 16.v1.1995, 29.vi.1995, 31.vii.1995

(A.T. Finnamore) [APM]. BC: Chopaka,

12.v.1983 (S.G. Cannings); Chopaka,

SATH habitat, BGxhl SN pitfall trap

CH6-2, 23.vi.-18.vii.1996 (J. Jarrett); Fair-

view, White L., Big sage assoc., BGxhl

SWn, 7.vii.1996 (G.G.E. Scudder) [UBC];

Enderby, 22.vili. 1920 (W. Downes)

[UBC], as G. atra A. & S. in Parshley

(1921), Downes (1927) and Walley (1929);

Keremeos Creek, 2000' (607 m) sagebrush

flat, fall trap, 9.vu.1982, 16.vii.1982,

23.vi1.1982 (H. Kirk) [UBC]; near Oliver,

22-23.v.1958 (G.E. Ball) [UA]; Oliver,

29.v.1924 (P.N. Vroom) [PFC]; Oliver,

26.v.1945 (D. Blair) [UBC]; Oliver, IRI,

"Water tower', Purshia assoc., BGxhl AN,

pitfall trap U2-4, 1.vi.-7.vi1.1994 (G.G.E.

Scudder) [UBC]; Oliver, McIntyre Cr.,

3000' (915 m), 29.v.1958 (H. & A. How-

den) [CNC]; Oliver, 5 mi. N., 21.v.1958

(H. & A. Howden) [CNC]; Oliver, 8 mi.

N., 18.v.1958, 19.v.1958 (H. & A. How-

den) [CNC]; Osoyoos, 21.v.1924 (K.F.

Auden) [PFC]; Osoyoos, 19.v.1958 (H. &

A. Howden) [CNC]; Osoyoos, 49°03'N

119°31'W [Desert Centre], BGxhl

8PD/2AN:P, pitfall trap, 19.vi1.-17.viil.

1996, 23.v1.-28.v11.1997, 27.vil.-

17.vini.1997, 17.viti.-21.1x.1997 (J. Jarrett)

[UBC]; Osoyoos, East Bench, 22.viu. 1995

(G.G.E. Scudder) [UBC]; Osoyoos,

Haynes Ecol. Res., 11.v.1982, 15.v.1985

(S.G. Cannings) [UBC]; Osoyoos, Haynes

Ecol. Res., BGxhl AN, recovery after fire,

pitfall trap, 9.vi.-7.vil. 1994 (G.G.E.

Scudder) [UBC]; Osoyoos, IRI, Inkaneep,

Purshia Assoc., BGxhl AN, pitfall trap

T5-5, 6.vii.-9.vi1.1995 (G.G.E. Scudder)

[UBC]; Penticton, 17.v.1985 (R.J. Can-

nings) [UBC]; Quesnel, 11.v11.1948 (G.J.

Spencer) [CNC]; Rock Creek, 7.vi.1959

(L.A. Kelton) [CNC]; Ross _ Lake,

Okanagan Falls, 5.vi.1959 (R.E. Leech)

[CNC]; Vaseux L., 5.vu.1981 (S.G. Can-

nings) [UBC]; Vaseux L., 2000' (607 m),

13.v1.1983 (R.J. Cannings) [UBC]; Vaseux

L., 2-3 mi. E., 24.v.1958 (G.E. Ball) [UA];

White L., Okanagan Falls, ex. Plantago,

6.vu1.1985 (R.J. Cannings) [UBC]. SK:

Cypress Hills Prov. Pk., Rte. 221, 27.4 km.

E. Pt. Walsh prairie, 18.v.1976 (Danny

Shpeley, George E. Ball) [UA]; Regina,

2.vi.1943 (P. Larkin) [CNC].

G. ovalis has been reported to occur on

Pycnanthemum and Vernonia, and in the

United States ranges from Massachusetts

west to Montana, and south to Florida,

Arizona, Texas and Guatemala

(McPherson 1982). McPherson (1982)

provides a key to separate G. ovalis from

the other three species reported from Can-

ada (Maw ef al. 2000). In G. ovalis, the

metapleura laterally are impunctate, the

corium has a distinct ridge inside the costal

128 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

groove, the scutellum is gradually de-

clivent posteriorly, and the posterior border

of the pygophore in the male, when viewed

from below is weakly concave, and the

dorsal rim lacks numerous long setae pos-

teriorly.

Family TINGIDAE

Stephanitis takeyai Drake & Maa

BC: 174 339, Richmond, ex. Pieris

japonica (Thunb.) D. Don, 31 September

2001 (R. Costello) [CNC, UBC].

S. takeyai is an alien species in North

America, first reported on Pieris japonica

(Japanese andromeda) at Greenwich, Con-

necticut in 1946 (Bailey 1950). Subse-

quently, it has been reported in several

other eastern states (Dunbar 1974; Wheeler

1977) where it also occurs in nursery and

landscape plantings on Lindera bezoin (L.)

Blume (spicebush) and Sassafras albidum

(Nutt.) Nees (Wheeler 1977).

The occurrence of this tingid, com-

monly called the Andromeda Lace Bug, in

British Columbia represents the first record

of this alien species in Western North

America. It is likely the result of a separate

introduction via nursery stock.

S. takeyai can be separated from S. rho-

dodendri Horvath, another alien species in

Canada that has separate introductions in

both the east and west in Canada, by its

more inflated and higher pronotal hood, its

shorter lateral carinae on the pronotum,

and by the much darker markings on the

hood and hemelytra. The paranota are al-

most vertical in S. takeyai, whereas in S.

rhododendri they are more flared (Bailey

1950).

ACKNOWLEDGEMENTS

This research was supported by grants

from the Natural Sciences and Engineering

Research Council of Canada. I am in-

debted to the late Dr. R.C. Froeschner for

confirmation of some of the determina-

tions. I thank the following for loan of ma-

terial, or permission to study collections in

their institution: Drs. A.T. Finnamore

(APM), R.G. Foottit (CNC), T.A. Wheeler

(LM), L.M. Humble (PFC), and G.E. Ball

(UA). Dr. M.D. Schwartz determined the

specimen of Pinophylus carneolus in the

CNC.

REFERENCES

Bailey, N.S. 1950. An Asiatic tingid new to North America (Heteroptera). Psyche 57: 143-145.

Downes, W. 1927. A preliminary list of the Hemiptera and Homoptera from British Columbia. Proceed-

ings of the Entomological Society of British Columbia 23: 1-22.

Downes, W. 1935. Additions to the list of B.C. Hemiptera. Proceedings of the Entomological Society of

British Columbia 31: 46-48.

Dunbar, D.M. 1974. Bionomics of the andromeda lacebug. Stephanitis takeyai. Memoirs of the Connecti-

cut Entomological Society 1974: 277-289.

Froeschner, R.C. 1960. Cydnidae of the Western Hemisphere. Proceedings of the Untied States National

Museum 111: 337-680.

Froeschner, R.C. 1988. Family Pentatomidae Leach, 1815. The Stink Bugs, pp. 544-597. Jn T.J. Henry

and R.C. Froeschner (eds), Catalog of the Heteroptera, or True Bugs, of Canada and the Continental

United States. E.J. Brill, New York.

Knight, H.H. 1927. Descriptions of twelve new species of Miridae from the District of Columbia and

vicinity (Hemiptera). Proceedings of the Biological Society of Washington 40: 9-18.

Maw, H.E.L., R.G. Foottit, K.G.A. Hamilton and G.G.E. Scudder. 2000. Checklist of the Hemiptera of

Canada and Alaska. NRC Research Press, Ottawa.

McDonald, F.J.D. 1976. Revision of the genus Trichopepla (Hemiptera: Pentatomidae) in North America.

Journal of the New York Entomological Society 84: 9-22.

McPherson, J.E. 1982. The Pentatomoidea (Hemiptera) of Northeastern North America with emphasis on

the fauna of Illinois. Southern Illinois University Press, Carbondale and Edwardsville.

Paiero, S.M., S.A. Marshall and K.G.A. Hamilton. 2004. New records of Hemiptera from Canada and

Ontario. Proceedings of the Entomological Society of Ontario 134 (2003): 115-129.

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Rider, D.A. 1989. Review of the New World species of the genus Neottiglossa Kirby (Heteroptera: Penta-

tomidae). Journal of the New York Entomological Society 97: 394-408.

Schuh, R.T. 2001. Revision of New World Plagiognathus Fieber, with comments on the Palearctic fauna

and the description of a new genus (Heteroptera: Miridae: Phylinae). Bulletin of the American Mu-

seum of Natural History 266: 1-267.

Schwartz, M.D. and R.T. Schuh. 1999. New genera and species of conifer-inhabiting Phyline plant bugs

from North America (Heteroptera: Miridae). Journal of the New York Entomological Society 107:

204-237.

Schwartz, M.D. and G.G.E. Scudder. 2001. Miridae (Heteroptera) new to Canada with some taxonomic

changes. Journal of the New York Entomological Society 108(2000): 248-267.

Schwartz, M.D. and G.G.E. Scudder. 2003. Seven new species of Miridae (Heteroptera) from British

Columbia and Alaska, and synonymy of Adelphocoris superbus (Uhler). Journal of the New York

Entomological Society 111: 65-95.

Scudder, G.G.E. 1997. True Bugs (Heteroptera) of the Yukon, pp. 241-336. Jn H.V. Danks and J.A. Dow-

nes (eds), Insects of the Yukon. Biological Survey of Canada (Terrestrial Arthropods), Ottawa.

Scudder, G.G.E. 2000. Heteroptera (Hemiptera: Prosorrhyncha) new to Canada. Part 1. Journal of the

Entomological Society of British Columbia 97: 51-56.

Stoner, D. 1926. Pentatomoidea from western Canada. Canadian Entomologist 58: 28-30.

Wheeler, A.G. Jr. 1997. Spicebush and sassafras as new North American hosts of andromeda lace bug,

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79: 168-171.

130 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004 131

Lestes disjunctus Selys and L. forcipatus Rambur

(Odonata: Lestidae): Some Solutions for Identification

JOHN P. SIMAIKA! and ROBERT A. CANNINGS””

ABSTRACT

Five species of the damselfly genus Lesfes live in British Columbia, Canada, and of

these, Lestes forcipatus Rambur and L. disjunctus Selys are the most similar and most

difficult to separate morphologically. Females can be readily distinguished by the size of

the ovipositor, but males are difficult to separate. In British Columbia, L. disjunctus 1s

the more common, widespread and familiar species. Before 1998, L. forcipatus speci-

mens were mistaken for those of L. disjunctus because the former is primarily an eastern

North American species and because most Lestfes species are usually identified using

male characters. With the discovery that L. forcipatus 1s part of the western fauna, an

evaluation of the relative status of the two species in British Columbia is necessary. The

best method for separating the two species uses the length of the anterior lamina (part of

the secondary genitalia) as a unique character or as part of ratios using other measure-

ments. In addition, in at least western North America, L. forcipatus males are more pru-

inescent than those of L. disjunctus, especially on the thorax. Identification using the

pruinescence pattern was tested in the field and is recommended as a simple and accu-

rate method for western North America. Soaking Odonata specimens in acetone, a com-

mon technique used to preserve colours, damages surface pruinescence and should not

be used to preserve mature, pruinescent adults, including those of Lestes species. To

identify L disjunctus and L. forcipatus males treated in acetone, it may be necessary to

calculate ratios based on various character measurements. Future research should inves-

tigate spatial and temporal differences between the species, as well as modes of inter-

specific communication.

Key Words: Odonata, Lestes forcipatus, Lestes disjunctus, identification, British Co-

lumbia, pruinescence, acetone, anterior lamina.

INTRODUCTION

Five species of the damselfly genus

Lestes (Odonata: Zygoptera: Lestidae)

occur in British Columbia (BC), Canada:

L. congener Hagen (Spotted Spreadwing),

L. disjunctus Selys (Northern Spreadwing),

L. dryas Kirby (Emerald Spreadwing), L.

forcipatus Rambur (Sweetflag Spread-

wing), and L. unguiculatus Hagen (Lyre-

tipped Spreadwing). L. disjunctus is the

most common, widespread and familiar

Lestes species in the province, and one of

the most abundant odonates in Canada,

ranging as far north as the Arctic treeline

(Cannings 2002). It inhabits many types of

standing water habitats with abundant

aquatic vegetation and, in southern BC,

adults fly from mid-June to mid-October

(Cannings 2002).

L. forcipatus 1s generally much less

common than L. disjunctus, although it 1s

as abundant in some cold fen habitats, and

both species often occur at the same site. L.

forcipatus does not range as far north as L.

disjunctus and, although not known from

much of BC’s north, it has been collected

in the southeastern Yukon. In the western

Canadian Cordillera, it is most common in

sedge fens (Cannings 2002). Walker

"4402-1063 Foul Bay Road, Victoria, British Columbia, Canada V8S 4J3

‘ Royal British Columbia Museum, 675 Belleville Street, Victoria, British Columbia, Canada V8W 9W2

* Author to whom correspondence should be sent

132 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

(1953) described L. forcipatus habitat in

Ontario as "ponds, both temporary and

permanent, marshy lakes, and slow, weedy

streams". In BC L. forcipatus has been

collected from mid-June to mid-September

(Cannings 2002).

L. forcipatus was not reported in BC

until 1998, when it was first collected in

the Rocky Mountain Trench north of

Golden and subsequently found in many

other localities in the southeastern part of

the province. However, it probably has

long been a resident of the province; it was

long overlooked because of its close re-

semblance to L. disjunctus (Ramsay and

Cannings 2000). Before 1998, L. forci-

patus was not known west of Saskatche-

wan (Walker 1953, Westfall and May

1996), and had just recently been found in

Washington State, the first record west of

Montana (Ramsay and Cannings 2000).

The species is now known from seven

counties in that state and one in Idaho

(Paulson 2004). By 1999 L. forcipatus had

been discovered at several other BC loca-

tions farther south and west, and by 2000

had been collected on Vancouver Island.

Some of our old museum specimens of L.

disjunctus from many regions of the prov-

ince have been re-identified as L. forci-

patus, indicating that museum collections

across western Canada probably contain

many misidentified specimens.

Males of L. disjunctus and L. forcipatus

are difficult to separate, although numer-

ous characters have been employed in

identification (Walker 1953, Westfall and

May 1996, Catling 2002, Donnelly 2003).

The usual method of distinguishing the two

species and confirming their presence at a

location is through identification of the

females. In L. forcipatus females the ovi-

positor valves reach the tips of the cerci; in

L. disjunctus they do not (Walker 1953,

Cannings 2002) (Fig. 1).

Lestes species are usually brown, black,

metallic green or bronze above and mostly

pale below; especially in males, the head,

thorax, base and tip of abdomen become

pruinescent bluish white with age. Pruines-

cence (pruinosity) is a waxy substance

produced by the hypodermis in many

groups of Odonata and excreted on the

cuticular surface through porous canals

(Gorb 1994). Pruinescence is implicated in

thermal regulation in dragonflies (Garrison

1976, Paulson 1983) and is thought to play

a role in species recognition and intraspeci-

fic communication -- indeed, the patterns

of pruinescence in males may be a result of

sexual selection (Jacobs 1955, Corbet

1999). Therefore, pruinescence patterns

might offer good species identification

characters, especially in males.

The object of this project was to find

novel and definitive distinguishing charac-

teristics between males of L. disjunctus

and L. forcipatus, building on the studies

of workers in eastern North America.

Thus, we hope (a) to distinguish males in

the absence of associated females; (b) to

identify, with relative ease, the species in

the field, (c) to correct any misidentifica-

tions of specimens in BC museum collec-

tions; and (d) to establish accurate distribu-

tions for both species in BC. The first part

of the present work measures certain struc-

tures of the male genitalia to find the best

features to separate the species. The sec-

ond part quantifies the degree of pruines-

cence of adult males of each species.

MATERIALS AND METHODS

Specimens. We measured 50 male L. dis-

Junctus and 45 male L. forcipatus speci-

mens from localities in BC and Alberta

(two L. disjunctus only from Alberta) and

from Washington and Maine in the United

States. Eighty-four of the specimens were

from the Royal British Columbia Museum

(RBCM), Victoria; the others were bor-

rowed from the Spencer Entomological

Museum, UBC, Vancouver, and the Slater

Museum of Natural History, Tacoma, WA.

A list of the specimens and their collection

data is on file at the RBCM and is avail-

able on request. Most specimens were in

copula or in tandem, except for three L.

forcipatus and one L. disjunctus; thus, the

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

153

Figure 1. Lateral view of apex of female abdomen. Top, Lestes disjunctus; Bottom, L. forci-

patus. OV = ovipositor.

identities of almost all males were con-

firmed using the associated females.

Measurements. During examination, each

specimen was held by the base of the

wings using a small padded alligator clamp

soldered to a #7 insect pin. The pin was

inserted into a cork mount, and the speci-

men held in a standardized measuring posi-

tion. Specimens were examined at 100x

magnification and measurements were

made to 0.01 mm.

Thirteen characters were measured;

terminology follows Westfall and May

(1996) and Donnelly (2003).

Cercus (Fig. 2):

1. Distance from base of apical tooth to

base of basal tooth (AB).

2. Distance from apex of cercus to base

of apical tooth (AC).

3. Distance from swelling at medial

base of cercus to base of basal tooth (BB)

(not figured).

Secondary genitalia (abdominal segment

2) (Fig. 3):

4. Length of the anterior lamina

(anterior hamule) (AL). Walker (1952,

1953) did not explain how to measure the

lamina, but Catling (2002) and Donnelly

(2003) prefer to measure the ventral length

of the hamule from where it appears from

above sternite 1. He notes, however, that

specimens show different degrees of bend-

ing in abdominal segments | and 2 and

thus there is no good reference for the ha-

mule base. We measured the blade of the

lamina only.

5. Length of membranous shield of

sperm vesicle (MS) (penis vesicle of Cat-

ling (2002) and Donnelly (2003)).

6. Length of penis shaft (PS).

7. Length of sperm vesicle (SV).

Apex of abdominal segment 10 (Fig. 4):

8. Height of apical hood (HT). This

structure is a triangular projection on the

dorsal apex of abdominal segment 10. The

apex of the abdomen was viewed end-on.

9. Width of base of apical hood (HL).

10. Width of the abdomen (WA). The

greatest width of the abdomen measured

when the apex of the abdomen was viewed

end-on.

Other:

11. Length of abdominal segment 2

(S2). Measured in lateral view.

12. Length of abdominal segment 3

(S3). Measured in lateral view.

13. Width of head (HD). The distance

between the extreme lateral edges of the

eyes, measured dorsally.

We analysed the difference between

species for each character measured using

a z-test after checking for uniformity of

variance, using the MS Excel Data Analy-

sis Tool (Stinson and Dodge 2004).

Pruinescence.

Pterothorax (Fig. 5). We compared the

extent of pruinescence on the head, ptero-

thorax (fused mesothorax and metathorax),

and abdominal segments 1 to 10 between

males of the two species. Pterothoracic

pruinescence was divided into several

value categories, as follows: absent = 0,

low lateral (below interpleural suture) = 1,

mid lateral (below midline of mese-

134 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

BI~

/ nS

/ Kw

Figure 2. Dorsal view of male primary genitalia. Left, Lestes disjunctus; Right, L. forcipatus.

AB = distance between base of apical tooth and base of basal tooth of cercus, AC = distance

between base of apical tooth and apex of cercus, AT = apical tooth of cercus, BT = basal tooth

Figure 3. Ventral view of male secondary genitalia. AL = length of blade of anterior lamina,

MS = length of membranous shield of sperm vesicle, PS = length of penis shaft, SV = length of

sperm vesicle, S2 = abdominal segment 2, S3 = abdominal segment 3.

Figure 4. Diagrammatic apical view of abdominal segment 10 of male Lestes disjunctus. HT =

height of apical hood, HL = width of base of apical hood, WA = width of abdomen.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

135

Figure 5. Lateral view of thorax of Lestes disjunctus male. Stippling represents coverage of

pruinescence: A, low lateral; B, mid lateral; C, complete lateral.

pimeron)= 2, complete lateral (below me-

sepisternal stripe) = 3, lateral+dorsal

(complete lateral plus mesepisternal stripe

and dorsal midline) = 4, complete thorax

(ventral + lateral + dorsal) = 5. Because

specimens had been treated in acetone and

the pruinescence patterns were thus dam-

aged, both sides of the pterothorax were

compared, and the more pruinescent side

recorded.

Abdominal segment 2 (Fig. 6). We exam-

ined segment 2 for presence or absence of

a rectangular patch free of pruinescence

and covering about the apical one-third of

the tergite. If the patch was present, we

assigned a value of 1; if absent, a value of

RESULTS

Measurements. Nine measurements failed

to show a significant difference between

the species: AC, BB, HT, HD, MS, PS, S3,

SV and WA.

Table 1 summarizes the seven measure-

ments that we consider important to this

study; these include the mean, standard

deviation, range and significance values

for z-tests. In Table | the z-test values for

the HD, S3, and WA are not significant.

However, tests of the same measurements

in character ratios show significant differ-

ences between the species.

Ratios of character measurements are

often useful in preventing individual size

variation from obscuring the value of a

character when comparing species varia-

tion. Analysis showed that several charac-

ter ratios calculated were not useful in

separating the two species: AB/AC, AB/

AL, AC/AL, AC/HD, BB/HD, HL/AL,

HT/HD, HT/HL, HT/WA, SV/AL, SV/S2,

MS/AL, MS/HD, MS/S2, PS/HD, S3/HD,

SV/HD, WA/HD. The significant character

ratios for both L. forcipatus and L. disjunc-

tus are summarized in Table 1.

Pruinescence. The head and abdominal

segment 1 were pruinescent in all speci-

mens; the pruinescence on segments 3-10

was not significantly different. All com-

parisons were inconclusive except for

those of the pterothorax and abdominal

segment 2.

Pterothorax (Table 2). In all specimens of

both species, the pterothorax was pruines-

cent. In L. forcipatus, it was completely

pruinose (covered ventrally, laterally and

dorsally) 72.5% (n = 40) of the time; L.

disjunctus was never completely pruines-

cent, and never covered dorsally. L. forci-

patus was covered completely laterally and

dorsally in 20% of specimens but never

showed only low lateral or mid lateral pru-

inescence. Of the 40 specimens measured,

three (7.5%) had only the lateral area com-

pletely covered. L. disjunctus was com-

pletely covered laterally 60.0% (n = 30),

mid laterally 30%, and low laterally 10%

of the time.

Abdominal segment 2. Segment 2 1n all L.

forcipatus specimens had a distinct dorsal

bare patch. In L. disjunctus an indistinct,

different sort of patch was present 23.1%

(n = 26) of the time. It was both asymmet-

rical and lightly pruinescent. The average +

SD patch size (n = 28) in L. forcipatus was

0.67 + 0.13 mm long, by 0.50 + 0.11 mm

wide.

136 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

PR om _— PT S2

Figure 6. Lateral view of thorax and abdominal segments 1 and 2 of fully pruinescent males.

Left, Lestes disjunctus; Right, L. forcipatus. PR = prothorax, PT = pterothorax, S2 = abdomi-

nal segment 2.

Table 1.

Summary statistics of measurements and ratios made for Lestes forcipatus and L. disjunctus.

Two-tailed z-tests were used to compare characters between species. Distances measured are as

follows: AB = apical tooth of cercus to basal tooth of cercus, AL = length of blade of anterior

hamule, HD = width of head, HL = width of base of apical hood, S2 = lateral length of ab-

dominal segment 2, S3 = lateral length of abdominal segment 3, WA = width of abdomen.

Character L. forcipatus L. disjunctus z-test results

Distance Mean SD Range n Mean SD Range n Z (Z<=2)

AB 0.51 0.04 047-060 42 045 0.05 033-053 46 6.10 0.00

AL 0.91 0.09 0.67-1.20 44 0.72 0.06 060-1.00 50 11.37 0.00

HD 4.73 0.16 433-500 39 4.77 O19 4.33-5.07 42 -0.89 0.37

HL 0.53 0.06 040-0.67 41 044 0.05 033-053 45 7.42 0.00

S2 2.57 0.16 2.27-2.87 44 240 0.13 213-267 50 5.47 0.00

S3 4.32 0.24 3.87-487 44 434 0.26 3.93-5.00 50 -041 0.68

WA 1.27 0.009 1.13-1.53 41 1.27 0.10 100-140 45 0.16 0.87

(Z<=2)

AB/HD 0.11 0.01 0.10-0.13 37 0.09 0.01 0.07-0.11 40 6.65 0.00

AL/HD 0.19 0.02 0.14-0.24 39 O15 O01 014-020 42 11.99 0.00

AL/S2 0.35 0.03 0.27-042 44 0.30 0.03 0.25-039 49 8.27 0.00

AL/S3 0.21 0.02 0.14-0.26 44 0.17 0.01 014-022 49 11.08 0.00

HL/HD 0.11 0.01 0.08-0.14 36 0.09 0.01 0.07-0.11 38 7.50 0.00

HL/WA 0.42 0.04 0.30-0.50 41 035 0.04 0.28-0.47 45 7.53 0.00

S2/HD 0.55 0.03 0.48-0.59 39 0.51 0.02 0.47-054 42 7.74 0.00

$2/S3 0.60 0.03 052-064 44 055 0.02 050-060 49 8.57 0.00

Ratio Mean SD Range n Mean SD Range n Z

DISCUSSION

Measurements. The search for diagnostic tinction between the two species is by

characters to differentiate L. forcipatus Garman (1917), who illustrated the longer

males from those of L. disjunctus is not a —_—ovipositor in L. forcipatus. Montgomery

new one. According to Donnelly (2003), (1941) noted the widespread confusion

the earliest paper that demonstrates a dis- between the species and cited four diag-

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

137

Table 2.

Percentage of specimens of Lestes forcipatus and L. disjunctus displaying selected patterns of

pruinescence on the pterothorax. Figs. 5 and 6 illustrate the patterns.

L. forcipatus L. disjunctus

Pruinosity pattern % (n=40) % (n=30)

Lateral-ventral-dorsal i235 0

Dorso-lateral 20 0

Complete lateral Ind 60

Mid lateral 0 30

Low lateral 0 10

Absent 0 0

nostic differences: (1) distance between

teeth of cercus; (2) width of apical hood of

abdominal segment 10; (3) width of base

of membranous shield of sperm vesicle

(penis vesicle), and (4) shape of penis (see

Donnelly 2003). When Walker (1952) re-

viewed Montgomery’s findings, he re-

jected the shape of the penis, but retained

the other three characters. Walker (1952)

added the relative lengths of abdominal

segments 2 and 3 and the length of the

anterior lamina (see Donnelly 2003).

Westfall and May (1996) also base their

separation of the species on the relative

lengths of abdominal segments 2 and 3, but

added the distance between the tip of the

basal tooth and the swelling near its base,

the shape of the membranous shield of the

sperm vesicle and the relative size of the

cercal teeth.

Donnelly’s (2003) findings are different

again. He stressed the use of the anterior

lamina length, the distance between the

apical and basal teeth on the cercus, the

shape of the paraproct and the apical hood

width on segment 10. He preferred not to

use the membranous shield, the relative

lengths of abdominal segments 2 and 3,

and the distance from the basal swelling of

the cercus to the tip of the basal tooth. Cat-

ling’s (2002) useful study of Ontario mate-

rial concluded that the best characters were

the relative heights of the apical and basal

teeth of the cercus and the relative extent

of pale and dark pigment (not pruines-

cence) on the thorax.

Our findings support the conclusion

that it is best to use a combination of char-

acters for identification. In western North

America, at least, both morphology and the

pattern of pruinescence should be consid-

ered. A short review of useful characters

and character ratios follows:

1. Anterior lamina (AL). Rather than meas-

uring the whole length of the lamina

(including the stalk), we measured the ex-

panded apical blade-like part only. The

lamina in L. forcipatus is longer (mean =

0.91 mm) than that of L. disjunctus (mean

= 0.72 mm). The ranges of the lengths of

the AL overlap in the two species, but the

length in L. disjunctus does not exceed 1

mm, while that of L. forcipatus reaches

1.20 mm. We found the lamina to be sig-

nificantly different in three character ratios

— those using the head width, the length of

segment 2 and the length of segment 3.

2. Base of apical tooth to base of basal

tooth (AB). AB is a good identification

character as a simple measurement or as a

ratio with head width (Table 1). The dis-

tance between the teeth is longer in L. for-

cipatus than in L. disjunctus; this result 1s

supported by Donnelly (2003). Although

there is some overlap in the measurements

of the two species (L. disjunctus, 0.33 —

0.53 mm; L. forcipatus,0.47 — 0.60 mm),

the character 1s useful when used in con-

junction with others.

3. Width of the apical hood (HL)

The ranges of apical hood widths over-

lapped in the two species -- L. disjunctus

(0.33 — 0.53 mm) and L. forcipatus (0.40 —

0.67 mm). The HL is generally greater in

138 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

L. forcipatus, which gives the apical hood

the wide, low appearance (as opposed to

the pinched shape in L. disjunctus) that 1s

often used to distinguish the species

(Donnelly, 2003, Lam 2004). Based on our

data, this is a generalization and is not reli-

able for differentiating the species. The HL

is useful when used in ratios using the head

and abdomen.

4. Width of the head (HD). There was no

significant difference between the species

in the width of the head. We used the

measurement to calculate ratios.

5. Lateral lengths of abdominal segments 2

and 3. There was a significant difference

between the length of segment 2 in both

species; however, the ranges overlapped

considerably. Segment 3 was not different

between species but the relative lengths of

segments 2 and 3 were significant.

6. Width of the abdomen (WA). This meas-

urement is significant only when used in a

ratio with measurements of the apical

hood. Comparing species using this char-

acter 1s difficult as the ranges overlap

greatly.

Pruinescence. The literature from eastern

North America, where L. forcipatus has

been studied for decades, does not mention

pruinescence as a basis for separating L.

disjunctus and L. forcipatus (Walker 1952,

1953, Westfall and May 1996, Catling

2002, Donnelly 2003, Lam 2004). In that

region, pruinescence patterns are appar-

ently different from those in northwestern

North America and are of little use in spe-

cies identification. On the other hand, as

was originally noted in Washington State

by Dennis Paulson, (D.R. Paulson, Slater

Museum, University of Puget Sound, Ta-

coma; pers. comm.), in far western North

America, pruinescence in mature individu-

als seems a good character for separating

the species. It has the advantage of being

easy to use 1n the field without even having

to capture the specimen. Further study of

these patterns over the whole range of the

two species 1s required.

Maturity 1s accompanied by pruines-

cence on abdominal segments 2, 8, 9, and

10, and to a lesser degree on abdominal

segments 3, 6, and 7. Patterns on abdomi-

nal segments other than segment 2 are not

useful in identification because they are

almost identical in shape, intensity and

frequency of occurrence in both species.

Abdominal segment 2 however, is reliable

in differentiating L. disjunctus and L. forci-

patus (Table 2.). Although 23% of L. dis-

junctus appear to have a clear patch at the

apex of this segment it has, upon closer

inspection, not a clearly defined rectangu-

lar shape but an asymmetrical shape with

some pruinscence throughout. There was

little individual variation in the position of

pruinescence in either L. forcipatus or L.

disjunctus.

Conclusions. Even with careful analysis of

each character, a specimen lacking pru-

inescence is difficult to identify. As a gen-

eral rule, a specimen with longer or wider

measurements than the average L. disjunc-

tus specimen should be regarded as a po-

tential L. forcipatus. The most worthwhile

characters to choose for identification are

the AB (the distance between the base of

the apical tooth and the base of the basal

tooth of the circus), AL (the length of the

blade of the anterior lamina), HL (the basal

width of the apical hood), and S2 (the lat-

eral length of abdominal segment 2). In

each, the mean distance is higher in L. for-

cipatus and, although ranges overlap con-

siderably, the range exceeds that of L. dis-

junctus.

The most useful ratios are the above

measurements divided by the head width

(AB/HD, AL/HD and HL/HD). In AB/HD

the ranges of the two species overlap mini-

mally compared to those of the other sig-

nificant ratios. In the remaining two ratios

the range of L. forcipatus far exceeds that

of L. disjunctus.

In our study, any specimen with pru-

inescence on the dorsum of the pterothorax

(mesepisternal stripe plus midline) is L.

forcipatus, and the species showed this

trait in over 90% of the specimens exam-

ined. L. forcipatus never had only low lat-

eral or mid lateral pruinescence, a common

pattern in L. disjunctus, and showed com-

plete lateral coverage (without any dorsal

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

pruinescence) only 7.5% of the time, com-

pared to 60% of L. disjunctus specimens.

Any specimen with a strongly differenti-

ated, symmetrical, pruinescent-free patch

apically on the dorsum of abdominal seg-

139

ment 2 was L. forcipatus. The segment in

L. disjunctus was usually completely pru-

inescent; about a quarter of the time it was

marked with an irregular, lightly pruines-

cent patch.

ACKNOWLEDGEMENTS

Dennis Paulson (Slater Museum of

Natural History, Tacoma), Karen Needham

and Rex Kenner (Spencer Entomological

mens. Dennis Paulson gave useful advice

concerning pruinescence patterns. Richard

Ring read an early draft of the manuscript.

Museum, UBC, Vancouver) loaned speci-

REFERENCES

Cannings, R.A. 2002. Introducing the Dragonflies of British Columbia and the Yukon. Royal British Co-

lumbia Museum, Victoria, BC.

Catling, P.M. 2002. An evaluation of some characters separating male Lestes disjunctus and Lestes forci-

patus in Ontario. Ontario Odonata 3: 51-58.

Corbet, P.S. 1999. Dragonflies: Behaviour and Ecology of Odonata. Cornell University Press. Ithaca, NY.

Donnelly, T.W. 2003. Lestes disjunctus, forcipatus and australis: a confusing complex of North American

damselflies. Argia 15(3): 10-13.

Garman, P. 1917. The Zygoptera or damsel-flies of Illinois. Bulletin of the Illinois State Laboratory of

Natural History 12(4): 411-587.

Garrison, R.W. 1976. Multivariate analysis of geographic variation in Libellula luctuosa Burmeister

(Odonata: Libellulidae). Pan-Pacific Entomologist 52: 181-203.

Gorb, S.N. 1994. Scanning electron microscopy of pruinosity in Odonata. Odonatologica 24(2): 225-228.

Jacobs, M.E. 1955. Studies on territorialism and sexual selection in dragonflies. Ecology 36: 566-586.

Lam, E. 2004. Damselflies of the Northeast. Biodiversity Books, Forest Hills, NY.

Montgomery, B.E. 1941. Records of Indiana dragonflies. X. 1937-1940. Proceedings of the Indiana Acad-

emy of Sciences 50: 229-241.

Paulson, D.R. 1983. A new species of dragonfly, Gomphus (Gomphurus) lynnae spec. nov., from the

Yakima River, Washington, with notes on pruinosity in Gomphidae (Anisoptera). Odonatologica 12

(1): 59-70.

Paulson, D.R. 2004. Western US Odonata range maps: Lestes forcipatus. http://www.ups.edu/biology/

museum/westernOD.html

Ramsay, L.R. and S.G. Cannings. 2000. Dragonflies at Risk in British Columbia. Vol. I, pp. 89-93. Jn L.

Darling (ed.), At Risk: Proceedings of a Conference on the Biology and Management of Species and

Habitats at Risk, Kamloops, BC, 15-19 February 1999. Ministry of Environment, Lands and Parks,

Victoria, BC.

Stinson, C. and M. Dodge. 2004. Microsoft Office Excel 2003: Inside Out. Microsoft Press. Redmond,

WA.

Walker, E.M. 1952. Lestes disjunctus and forcipatus complex (Odonata: Lestidae). Transactions of the

American Entomological Society 88: 59-74.

Walker, E.M. 1953. The Odonata of Canada and Alaska. Vol. 1. University of Toronto Press, Toronto,

ON.

Westfall, M.J., Jr., and M.L. May. 1996. Damselflies of North America. Scientific Publishers, Inc. Gaines-

ville, FL.

140 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

14]

SCIENTIFIC NOTE

A ground-based pheromone trap for monitoring

Agriotes lineatus and A. obscurus (Coleoptera: Elateridae)

R.S. VERNON!

The dusky click beetle, Agriotes obscu-

rus (L.) and the lined click beetle, A. /inea-

tus (L.) were introduced to British Colum-

bia (BC) from Europe about a century ago,

and are now serious pests of several crops

(e.g. corn, cereals, potatoes) in the lower

Fraser Valley and Vancouver Island

(Wilkinson 1963). Prior to 1999, delimita-

tion surveys of these species in North

America were based on: inspections of

click beetles in existing private or national

collections (Eidt 1953; Vernon and Pats

1997); habitat searches (Brown 1950); or

click beetles taken in strategic arrays of

pitfall traps (Vernon and Pats 1997). A

major breakthrough in the monitoring of A.

obscurus and A. lineatus has been the iden-

tification of sex pheromones for these and

other Agriotes species in the former USSR

and Europe (e.g. Borg-Karlson ef al.

1988). These pheromones were used suc-

cessfully to survey the distribution of pest

Agriotes species across the former USSR

(Kudryavtsev et al. 1993). Based on this

work, various pheromone blends were suc-

cessfully tested for attractiveness to A.

obscurus and A. lineatus in the lower Fra-

ser Valley in 1999, and an effective proto-

type ground-based pheromone trap was

concurrently developed (RSV unpublished

data).

A simpler commercial version of the

prototype pheromone trap was _ subse-

quently designed (currently known as the

Vernon Beetle Trap, Phero Tech Inc.,

Delta, BC), and was used in delimitation

surveys of A. obscurus and A. lineatus in

BC and Washington State in 2000 and

2001 (Vernon et a/. 2001). The trap design

(details of which were not disclosed previ-

ously for proprietary reasons) has now

been granted a U.S. Industrial Design pat-

ent (US Patent # Des. 465,254) and details

of this trap can now be presented.

The trap (Fig. 1A) is constructed of

durable polyvinyl chloride (PVC), and

consists of two components formed from

extrusion molds (Figs. 1B &C). The main

component is an open ended box (Fig. 1B),

the inside dimensions of which are 15.2 cm

wide by 5 cm high. The other component

is a ramp section (Fig. 1C), two of which

are inserted into opposite ends of the open

box. To assist beetles in climbing, the

ramp section has 27, 0.2 mm high parallel

ridges, spaced 2 mm apart, ending in a

smooth downward curved section at the

top. The ramp (width = 15.2 cm) slides

easily into slots in the floor of the box

component, with the ramp section angled

upwards at 40° from the box floor. The top

of the ramp is held at 3 mm from the top of

the box component by indentations in the

upper box corners and by 3 ridges extend-

ing downwards 3 mm into the box. The

gap formed between the ramp top and ceil-

ing of the box enables Agriotes click bee-

tles to enter, while impeding entry by lar-

ger insects (e.g. large carabids) and other

insectivores (e.g. voles). The ramp section

also contains 2 parallel 7.0 mm deep pro-

trusions, spaced 0.2 mm apart to allow for

insertion of bubble cap pheromone release

devices (Phero Tech Inc.). The length of

the box component is 15.4 cm, such that

when ramp sections are fully inserted into

the open ends the opposing ramps are | cm

apart at the curved apex. When deployed,

the traps are placed at ground level, with

the downward edges of the box section

pushed into the soil, and the fully inserted

entry ramps flush with and slightly covered

by soil to provide unimpeded beetle entry.

When properly installed, the traps can

‘Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, P.O. Box 1000, Agassiz, British

Columbia, Canada VOM 1A0

142 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

Figure 1. Photographs of a dismantled click beetle pheromone trap (A), showing the box section (B)

and ramp section (C). Labelled details include: a) bubble-cap pheromone lure; b) floor slot for ramp

insertion; c) lure clasp; d) ramp section with climbing ridges; and e) ramp insertion point.

often attract male A. obscurus and A. linea-

tus beetles within a few minutes. Trapping

efficacy remains high throughout the adult

generation of both species (Vernon ef al.

2001), and other genera of click beetles are

rarely captured. Traps with A. J/ineatus

lures seldom catch A. obscurus, whereas A.

obscurus traps will catch significant num-

bers of A. lineatus. Catch of A. lineatus in

A. obscurus traps, however, can be almost

eliminated if traps for both species are

placed within 1.5 m of each other (RSV,

unpublished data).

In a trial conducted in Agassiz B.C.

comparing the relative efficacy of the new

traps versus pitfall traps used in earlier

elaterid surveys (Vernon and Pats 1997),

the pheromone traps caught 54.3 A. obscu-

rus per trap compared with only 1.6 A.

obscurus caught per pitfall trap over a one

month period in 2001. During this trial,

escapes, and/or predation of click beetles

caught in the pitfall traps was common, but

was not observed in the pheromone traps.

Some predation of click beetles by certain

carabids (e.g. Pterostichus melanarius

Illiger) will occur in pheromone traps left

untended for 2-3 week periods late in the

adult generations of A. obscurus and A.

lineatus (RSV pers. obs.). When deployed

in undisturbed areas and inspected rou-

tinely (10-14 days), however, the new

pheromone traps provide an effective, con-

venient and inexpensive method for sur-

veying and detecting A. obscurus and A.

lineatus populations.

REFERENCES

Borg-Karlson, A.K., L. Agren, H. Dobson and G. Bergstrém. 1988. Identification and electroantennographic

activity of sex-specific geranyl esters in an abdominal gland of female Agriotes obscurus (L.) and A.

lineatus (L.) (Coleoptera: Elateridae). Experientia 44: 531-534.

Brown, W.J. 1950. The extralimital distribution of some species of Coleoptera. The Canadian Entomologist

82: 197-205.

Eidt, D.C. 1953. European wireworms in Canada with particular reference to Nova Scotian infestations. The

Canadian Entomologist 85: 408-414.

Kudryavtsev, I., K. Siirde, K. Laats, V. Ismailov and V. Pristavko. 1993. Determination of distribution of

harmful click beetle species (Coleoptera: Elateridae) by synthetic sex pheromones. Journal of Chemical

Ecology 19:1607-1611.

Vernon, B. and P. Pats. 1997. Distribution of two European wireworms, Agriotes lineatus and A. obscurus in

British Columbia. Journal of the Entomological Society of British Columbia 94: 59-61.

Vernon, B., E. Lagasa and H. Philip. 2001. Geographic and temporal distribution of Agriotes obscurus and

A. lineatus (Coleoptera: Elateridae) in British Columbia and Washington as determined by pheromone

trap surveys. Journal of the Entomological Society of British Columbia 98: 257-265.

Wilkinson, A.T.S. 1963. Wireworms of cultivated land in British Columbia. Proceedings of the Entomologi-

cal Society of British Columbia 60: 3-17.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

143

SCIENTIFIC NOTE

Parasitoids of Leptoglossus occidentalis Heidemann

(Heteroptera: Coreidae) in British Columbia

SARAH L. BATES!” and JOHN H. BORDEN"?

ABSTRACT— Eggs of the western conifer seed bug, Leptoglossus occidentalis Heide-

mann, were parasitized in the field in British Columbia, Canada, by Gryon pennsylvani-

cum (Ashmead), Anastatus pearsalli Ashmead and an unidentified Ooencyrtus spp. Ash-

mead. Leptoglossus occidentalis represents a new host record for all three parasitoids.

Gryon pennsylvanicum has not previously been reported 1n Canada.

The western conifer seed bug, Lep-

toglossus occidentalis Heidemann, feeds

on several species of conifers (Hedlin ef ai.

1981), and can cause substantial yield

losses in high-value seed orchards (Bates

et al., 2002; Strong et a/. 2001). The gen-

eralist egg parasitoid, Anastatus bifasciatus

(Geoffroy) (Hymenoptera: Eupelmidae),

has recently been recovered from L. occi-

dentalis egg masses in Italy (Camponogara

et al. 2003) but little else is known about

egg parasitoids of L. occidentalis

Members of the family Scelionidae are

egg parasitoids of several economically-

important hemipteran pests (Masner 1983).

Gryon pennsylvanicum (Ashmead) is a

polyphagous, solitary parasitoid of coreids,

including Anasa tristis (De Geer) and sev-

eral Leptoglossus species other than occi-

dentalis (Masner 1983; Mitchell 1983;

Yasuda 1990; Daane et al. 2001). Anas-

tatus pearsalli Ashmead (Hymenoptera:

Eupelmidae) is widely distributed through-

out the nearctic, and parasitizes hosts from

several orders and families including

Coreidae (Burks 1979). Members of the

genus Ooencyrtus (Hymenoptera: Encyrti-

dae) are also common egg parasitoids of a

number of orders and families (Gordh

1979). We report on the occurrence of G.

pennsylvanicum, A. pearsalli and Ooencyr-

tus sp. in B.C. in a previously undocu-

mented host, L. occidentalis.

Leptoglossus_ occidentalis eggs were

obtained by caging adult females on cone-

bearing branches of lodgepole pine, Pinus

contorta var. latifolia Engelmann, at

Kalamalka Seed Orchard, Vernon, B.C.

(50.27 °N, 119.28 °W). In 2001, females

were collected from orchard trees, and in

2002 they were obtained from an outdoor

colony of overwintered insects maintained

at Simon Fraser University. Eggs were

laid in a single row along needles, and

were collected by removing the entire nee-

dle. Ten egg masses, each bearing 10-13

eggs, were transferred to separate trees

throughout the orchard on 5 July in 2001.

In 2002, 24 egg masses were set out on

trees on 30 June. Wire paper clips were

used to fasten egg-bearing needles to foli-

age. Eggs were 0-7 d old at the time of

transfer. After three weeks, all unhatched

eggs were transferred to Petri dishes, main-

tained at room temperature in the labora-

tory and monitored for parasitoid emer-

gence. Voucher parasitoid specimens were

deposited in Canadian National Collection

of Insects, Agriculture and Agri-Food Can-

ada, Ottawa, Ontario.

In 2001, 32.7% of eggs were parasi-

tized by an_ unidentified scelionid(s),

prompting a more systematic study in the

following year. In 2002, parasitoids

Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada VS5A

1S6

Current address: BIOCAP Canada Foundation, Queen’s University, 156 Barrie St., Kingston, ON, Can-

ada K7L 3N6, sb339@cornell.edu

* Current address: PheroTech Inc., 7572 Progress Way, Delta, B.C. V4G 1E9 Canada

144 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

emerged from ca. 29% of L. occidentalis

eggs. Gryon pennsylvanicum was the

predominant parasitoid, attacking 87% of

parasitized eggs. The remaining parasi-

tized eggs were parasitized by Anastatus

pearsalli (8%) and an_ unidentified

Ooencyrtus sp. (Hymenoptera: Encyrti-

dae) (4%). One parasitoid failed to com-

plete its development and was not identi-

fied. Leptoglossus occidentalis has not

previously been recorded as a host for any

of these parasitoids.

Natural rates of parasitism of L. occi-

dentalis eggs may vary at other times dur-

ing the season. In addition, the use of eggs

that were up to 7 d old may have affected

the level of parasitism, because older eggs

would have been acceptable to parasitoids

for a shorter period of time. However, the

relatively high level of parasitism observed

in this study suggests that biological con-

trol with egg parasitoids could serve as a

potential component of an integrated pest

management program for L. occidentalis in

B.C. seed orchards. Further study will be

necessary to identify the full parasitic guild

of this insect, its temporal synchronicity

with L. occidentalis, and the density of

wasps required to reduce seed bug popula-

tions. Anastatus bifasciatus, which was

introduced into the eastern U.S. to control

gypsy moth in the early 1900’s (Crossman,

1925), may form part of the natural enemy

complex of L. occidentalis in at least some

regions of North America.

We thank Lubomir Masner and Gary

Gibson, Agriculture and Agri-Food Can-

ada, for parasitoid identification, and Chris

Walsh and Ward Strong, B.C. Ministry of

Forests, for allowing us access to

Kalamalka Seed Orchard and providing

advice. We also thank Andrea Battisti,

Universita di Padova, Italy, for helpful

discussion. This research was supported

by the B.C. Ministry of Forests, the Natu-

ral Sciences and Engineering Research

Council of Canada, the Science Council of

B.C., and 21 forest companies.

REFERENCES

Bates, S.L., C.G. Lait, J.H. Borden and A.R. Kermode. 2002. Measuring the impact of Leptoglossus occiden-

talis (Hemiptera: Coreidae) on seed production in lodgepole pine using an antibody-based assay. Journal of

Economic Entomology 95: 770-777.

Burks, B.D. 1979. Family Eupelmidae. p. 878-889. In: K.V. Krombein, P.D. Hurd, Jr., D.R.Smith, B.D. Burks

(Eds.) Catalog of Hymenoptera in America North of Mexico Vol. I, Smithsonian Institute Press, Washing-

ton, D.C.

Camponogara, P., M. Festi, and A. Battisti. 2003. La cimice dei semi americana: unospite indesiderato

delle conifere. Vita in Campagna 2003: 7-8.

Crossman, S.S. 1925. Two imported egg parasites of the gipsy moth Anastatus bifasciatus Fonsc. and Sche-

dius kuwanae Howard. Journal of Agricultural Research 30: 643-675.

Daane, K.M., G.Y. Yokota, K. Weir and S.A. Steffan. 2001. Biological investigations of hemipteran pests to

improve control and reduce the spread of the fungus Botryosphaeria dothidea. Annual Report, Crop Year

2000-2001, California Pistachio Industry, Fresno, CA, p. 1-7.

Gordh, G. 1979. Encyrtidae, p. 890-967. In: K.V. Krombein, P.D. Hurd, Jr., D.R.Smith, B.D. Burks (Eds.)

Catalog of Hymenoptera in America North of Mexico Vol. I, Smithsonian Institute Press, Washington,

D.C.

Hedlin, A.F., H.O. Yates, D.C. Tovar, B.H. Ebel, T.W. Koerber and E.P. Merkel. 1981. Cone and Seed

Insects of North American Conifers. Canadian Forestry Service, USDA Forest Service and Secretaria

de Agricultura y Recursos Hidraulicos, Mexico, 122 p.

Masner, L. 1983. A revision of Gryon Haliday in North America (Hymenoptera: Proctotrupoidea: Scelioni-

dae). The Canadian Entomologist 115: 123-174.

Mitchell, P.L. 1983. Range extensions of Leptoglossus fulvicornis with observations on egg parasitism.

Southwestern Entomologist 8: 150-153.

Strong, W.B., S.L. Bates and M.U. Stoehr. 2001. Feeding by Leptoglossus occidentalis Heidemann

(Hemiptera: Coreidae) reduces seed set in lodgepole pine. The Canadian Entomologist 133: 857-865.

Yasuda, K. 1990. Ecology of the leaf footed plant bug, Leptoglossus australis Fabricius (Heteroptera:

Coreidae), in the sub-tropical region of Japan. Tropical Agricultural Research Series 23: 229-238.

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

145

SCIENTIFIC NOTE

Evaluation of the antiaggregation pheromone, 3-

methylcyclohex-2-en-1-one (MCH), to protect live spruce

from spruce beetle (Coleoptera: Scolytidae)

infestation in southern Utah

DARRELL W. ROSS’, GARY E. DATERMAN?

and A. STEVEN MUNSON?

The spruce beetle, Dendroctonus

rufipennis (Kirby), produces the antiaggre-

gation pheromone 3-methylcyclohex-2-en-

l-one (MCH) (Rudinsky et al. 1974).

MCH has reduced the numbers of spruce

beetles attracted to infested logs and syn-

thetic semiochemical lures or reduced

colonization rates throughout the beetles

range (Kline et al. 1974, Rudinsky ef al.

1974, Furniss ef al. 1976, Dyer and Hall

1977, Lindgren ef al. 1989). MCH has not

prevented the infestation of live trees

(Werner and Holsten 1995), with one ex-

ception. MCH in a novel formulation in-

corporating a microinfusion pump pre-

vented the infestation of live spruce in

Alaska in an area with a low spruce beetle

population (Holsten et a/. 2003). The ob-

jective of this study was to test MCH using

commercially available diffusion releasers

for protecting live trees from spruce beetle

infestation in an area with a high spruce

beetle population in southern Utah.

Study plots were located about 20 km

east of Cedar City, Utah (lat. 37°38' N,

long. 112°49' W) at elevations of 3,000 to

3,200 m, in a spruce beetle outbreak area.

Circular, 1-ha plots were located in mixed

stands of mature Engelmann spruce, Picea

engelmanii Parry ex Engelm, and subal-

pine fir, Abies lasiocarpa Nutt. Two treat-

ments (MCH application and untreated

control) were replicated four times in

paired plots. Pairs were about 100 m apart

and replicates were 100-2,000 m apart.

Plots were established on 24 and 25 June

1998 prior to spruce beetle flight. MCH-

treated plots had 180 releasers stapled to

the north side of trees and snags around the

plot perimeter at a height of 2 m. Because

of availability limitations, two different

types of releasers were interspersed evenly

with one another on each plot, 110 of the

releasers were from IPM Technologies,

Inc., Portland, Oregon, (release rate, 9 mg/

day at 22 °C) and the other 70 releasers

were from Phero Tech, Inc., Delta, British

Columbia, Canada, (release rate, 7 mg/day

at 25 °C). A multiple-funnel trap baited

with a lure containing frontalin and a-

pinene in polyvinyl chloride formulations

each releasing 0.8 mg/day at 25 °C was

placed at the center of each plot to monitor

beetle activity. Traps were emptied on 2

and 7 July 1998, and were removed when

successful beetle colonization on trees

within the plots was first observed. The

basal area of all trees >20 cm diameter at

breast height (dbh) was measured at 30 m

from the plot center in the four cardinal

directions and recorded by species. Per-

cent spruce basal area was calculated.

Plots were surveyed on 17 September 1998

after beetle flight had ended to determine

the dbh and infestation status of all spruce

>20 cm dbh. Trees were classified as

mass-attacked or unattacked based on the

presence or absence of large amounts of

boring dust on the lower third of the bole.

Percentage of spruce trees >20 cm dbh that

were mass-attacked was calculated for

each plot.

Paired t-tests were used to test for

treatment differences in the total numbers

' Department of Forest Science, Oregon State University, Corvallis, OR 97331

“USDA Forest Service, Pacific Northwest Research Station, 3200 Jefferson Way, Corvallis, OR 97331

7 USDA Forest Service, Forest Health Protection, 4746 South 1900 East, Ogden, UT 84403

146 J. ENTOMOL. SOc. BRIT. COLUMBIA 101, DECEMBER 2004

of spruce beetles caught in the traps and in

the tree and stand data. Percentages of

spruce trees mass-attacked were arcsin

square root transformed. Nontransformed

means are reported.

There was no significant difference in

spruce beetle catches between MCH-

treated and untreated plots (P = 0.7430).

The average (+ SE) number of spruce bee-

tles caught in traps on MCH-treated plots

was 546 + 293 and the average caught in

traps on controls was 473 + 245. As ex-

pected, there were no significant differ-

ences between treatments for basal area (P

= 0.2113), percent of total basal area (P =

0.9409), tree density (P = 0.6715), or dbh

(P = 0.4592), since plots were selected to

be similar with respect to stand structure

and composition. Furthermore, the percent

of spruce >20 cm dbh that were mass-

attacked by the spruce beetle was not sig-

nificantly different on MCH-treated (52.7

+ 20.3%) and untreated plots (68.3 +

15.3%) (P = 0.4262). The majority, if not

all, of the colonized trees were heavily

infested.

The application rate of MCH used in

this study was more than twice the current

recommended dose for the Douglas-fir

beetle (Ross et a/. 2001). Despite the high

application rate, MCH was not effective in

preventing host-tree infestation by the

high-density spruce beetle population. The

lack of a significant effect of MCH might

have been related to release rates of the

compound under field conditions or to the

lack of a behavioral response of the species

to the compound. A recent study demon-

strated that spruce beetle host selection

behavior changes with population density

(Wallin and Raffa 2004) and this could

explain the different responses to MCH

that have been observed in field studies.

Further study will be needed to determine

the conditions under which MCH might be

operationally feasible for protecting live

spruce.

We thank Ron Wilson, Phil Eisenhauer,

and Lucy Wilkins of the Dixie National

Forest and Tom Henry, Steve Robinson,

and Rachael Turnbaugh of Cedar Breaks

National Monument for providing assis-

tance and access to the study sites. The

work upon which this publication 1s based

was funded in whole or in part through a

grant awarded by the Northeastern Area

State and Private Forestry, USDA Forest

Service.

REFERENCES

Dyer, E.D.A. and P.M. Hall. 1977. Effect of anti-aggregative pheromones 3,2-MCH and trans-verbenol

on Dendroctonus rufipennis attacks on spruce stumps. Journal of the Entomological Society of British

Columbia 74: 32-34.

Furniss, M.M., B.H. Baker, and B.B. Hostetler.

1976. Aggregation of spruce beetles (Coleoptera) to

seudenol and repression of attraction by methylcyclohexenone in Alaska. The Canadian Entomologist

108: 1297-1302.

Holsten E.H., P.J. Shea, and R.R. Borys. 2003. MCH released in a novel pheromone dispenser prevents

spruce beetle, Dendroctonus rufipennis (Coleoptera: Scolytidae), attacks in south-central Alaska.

Journal of Economic Entomology 96: 31-34.

Kline, L.N., R.F. Schmitz, J.A. Rudinsky, and M.M. Furniss.

1974. Repression of spruce beetle

(Coleoptera) attraction by methylcyclohexenone in Idaho. The Canadian Entomologist 106: 485-491.

Lindgren, B.S., M.D. McGregor, R.D. Oakes, and H.E. Meyer. 1989. Suppression of spruce beetle at-

tacks by MCH released from bubble caps. Western Journal of Applied Forestry 4: 49-52.

Ross, D.W., K.E. Gibson, and G.E. Daterman. 2001. Using MCH to protect trees and stands from Doug-

las-fir beetle infestation. U.S. Department of Agriculture Forest Service FHTET-2001-09.

Rudinsky, J.A., C. Sartwell Jr., T.M. Graves, and M.E. Morgan. 1974. Granular formulation of methyl-

cyclohexenone: an antiaggregative pheromone of the Douglas-fir and spruce bark beetles (Col., Scoly-

tidae). Zeitschrift fiir angewandte Entomologie 75: 254-263.

Wallin, K.F. and K.F. Raffa. 2004. Feedback between individual host selection behavior and population

dynamics in an eruptive herbivore. Ecological Monographs 74: 101-116.

Werner, R.A. and E.H. Holsten. 1995. Current status of research with the spruce beetle, Dendroctonus

rufipennis, pp. 23-29. In: S.M. Salom and K.R. Hobson (tech. eds.). Application of semiochemicals

for management of bark beetle infestations — Proceedings of an informal conference. U.S. Department

of Agriculture Forest Service General Technical Report INT-GTR-318

J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

147

SCIENTIFIC NOTE

New waterboatmen records for Western Canada

(Hemiptera: Corixidae)

R.D. KENNER! and K.M. NEEDHAM!

ABSTRACT— Trichocorixa verticalis (Fieber) is reported for the first time from the

mainland of British Columbia and the subspecific assignment is discussed. Based on

specimens in the Spencer Entomological Museum, one provincial record and one territo-

rial record are added to the recent checklist of Canadian Hemiptera.

During recent collecting trips in the

Lower Mainland of British Columbia

(BC), Canada, we found a population (both

immatures and adults) of Trichocorixa

verticalis (Fieber). Previously, T. verticalis

was known in BC only from three island

localities: two on Vancouver Island and

one on Thetis Island (Scudder 1977). A

fourth island record can be added to these:

Prevost Island, salt marsh _ pond,

10.v11.1986, J.D. Reynolds, 1 male, 2 fe-

males, Spencer Entomological Museum.

Outside of BC, Trichocorixa verticalis

has a widespread distribution. Two subspe-

cies occur on each of the east and west

coasts of North America with a fifth sub-

species broadly distributed through the

central plains (Sailer 1976). The subspe-

cies T. v. californica Sailer was described

based on specimens from central Califor-

nia (Sailer 1976) and its known distribu-

tion was subsequently extended north

through Oregon and Washington

(Stonedahl & Lattin 1986). All previous

BC records have been attributed to this

subspecies (Scudder 1977). Trichocorixa

verticalis californica is listed as potentially

rare or endangered in British Columbia

(Scudder 1994) and is considered a species

of special concern in the Georgia Depres-

sion Region (Scudder 1996).

The mainland Trichocorixa specimens

were collected in Delta, south of Vancou-

ver, from a ditch on the north side of Del-

taport Way in early October 2003 and

again in late May 2004. The ditch runs

inland from the coast and connects at its

coastal end to a second ditch that runs par-

allel to and just inland of the coastal dike.

In the October survey, semi-quantitative

data were collected between 1.3 km and

3.7 km inland from the dike. The density

of T. verticalis was found to drop sharply

beyond 1.8 km and no specimens were

collected more than 2.2 km from the dike.

In May, we extended the surveyed area to

the coastal dike; 7. verticalis was found at

all sites between 0 and 1.3 km inland.

While the assignment of the Delta

specimens to 7. verticalis was straightfor-

ward, the subspecific assignment was not.

In his key to subspecies of T. verticalis,

Sailer (1976) deals separately with female

and male specimens. Based on those keys,

our female specimens are 7. v. californica

but our male specimens are T. v. verticalis

(Fieber). The range for T. v. verticalis ex-

tends along the coast from Maine to Mex-

ico and includes the West Indies (Sailer

1976). In Sailer’s key, a critical character

for males is the ratio of the length of the

closest separation of the eyes (IO) to the

length of the hind margin of the eye (L,).

In T. v. californica the ratio is greater than

or equal to one; the ratio is less than one in

T. v. verticalis. In our specimens, IO:L, is

less than one. In order to check Sailer’s

key, this ratio was measured for two male

paratypes of T. v. californica (CA, San

Mateo Co., Moss Beach, 4.vu1.1929, R.L.

Usinger) and for two male specimens of 7.

v. verticalis (Bermuda Island, Spittal Pond,

10.vi11.1940, G. Kelly); all four specimens

are in the Essig Museum at the University

"Spencer Entomological Museum, Department of Zoology, University of British Columbia, Vancouver,

BC V6T 1Z4

148 J. ENTOMOL. SOC. BRIT. COLUMBIA 101, DECEMBER 2004

of California Berkeley. These four speci-

mens fulfill Sailer’s criteria.

In a further effort to identify our speci-

mens, we examined the left and night

claspers from one of the male specimens.

Comparison of these claspers with the

drawings for the various species of Tricho-

corixa in Sailer (1976) showed the best

agreement between our specimen and 7.

verticalis. However, within the subspecies

of T. verticalis, the claspers of our speci-

men are in poorest agreement with those

shown for T. v. californica; they are in

much better agreement with those of the

three more easterly subspecies.

We rechecked the identification of all

of the BC Trichocorixa specimens in the

Spencer Entomological Museum (three

localities with a total of two males, five

females and one immature). The five fe-

male specimens key out to T. v. califor-

nica. One of the males is teneral and is

partially collapsed; it cannot be run

through the key. The second male is dam-

aged but the ratio of IO: L. can be meas-

ured and is less than one, in agreement

with the Delta specimens. Thus at least one

of the male Trichocorixa specimens previ-

ously collected in BC also does not fit

Sailer’s description of 7. v. californica. It

is unclear whether the definition of 7. v.

californica needs to be broadened to ac-

count for the geographical variation repre-

sented by the BC specimens or if the BC

specimens belong to a different subspecies.

A re-examination of the whole question of

subspecific designations for 7. verticalis is

needed. In view of the uncertainty in as-

signing subspecies to the BC specimens,

we prefer to leave the determination as

simply T. verticalis.

‘In addition to T. verticalis, we collected

four other species of corixids from the

ditch in Delta: Cenocorixa _ blaisdelli

(Hungerford), Corisella inscripta (Uhler),

Hesperocorixa atopodonta (Hungerford)

and Sigara omani (Hungerford). Ceno-

corixa blaisdelli is listed as potentially rare

or endangered in_ British Columbia

(Scudder 1994) and Corisella inscripta is

listed as rare or very local in occurrence in

Canada (Maw ef al. 2000). These records

highlight the importance of surveying

these often overlooked habitats. Voucher

specimens for all of these records are in the

Spencer Entomological Museum.

Examination of the corixids in the col-

lection at UBC showed that two entries

were omitted from the recent Checklist of

Hemiptera of Canada and Alaska (Maw et

al. 2000), one each for BC and NT, based

on the following’ records:

Hesperocorixa minorella (Hungerford):

BC, Banks Is., Kooryet Bay, sphagnum

bog, 11.vi1.1986, G.G.E. Scudder, 1 male,

4 females; BC, Diana L., sphagnum bog,

14.vi1.1986, G.G.E. Scudder, 2 males.

Sigara lineata (Forster): NT, Hay R.,

Mackenzie Hwy., 20.v11.1961, T.G. North-

cote, 1 male, 2 females.

We thank G.G.E. Scudder for useful

discussions. RDK thanks Cheryl Barr for

her hospitality and access to the specimens

in the Essig Museum.

REFERENCES

Maw, H.E.L., R.G. Foottit, K.G.A. Hamilton and G.G.E. Scudder. 2000. Checklist of the Hemiptera of

Canada and Alaska. NRC Research Press, Ottawa, Ontario, Canada.

Sailer, R.I. 1976. The Genus Trichocorixa (Corixidae, Hemiptera). pp. 289-407 in: H.B. Hungerford. The

Corixidae of the Western Hemisphere. The University of Kansas Science Bulletin 32.

Scudder, G.G.E. 1977. An annotated checklist of the aquatic and semiaquatic Hemiptera (Insecta) of Brit-

ish Columbia. Syesis 10: 31-38.

Scudder, G.G.E. 1994. An annotated systematic list of the potentially rare and endangered freshwater and

terrestrial invertebrates in British Columbia. Entomological Society of British Columbia, Occasional

Paper 2, April 1994.

Scudder, G.G.E. 1996. Terrestrial and freshwater invertebrates of British Columbia: priorities for inven-

tory and descriptive research. Research Branch, BC Ministry of Forests, and Wildlife Branch, BC

Ministry of Environment, Lands and Parks, Victoria, BC, Working Paper 09/1996.

Stonedahl, G.M. and J.D. Lattin. 1986. The Corixidae of Oregon and Washington (Hemiptera: Heterop-

tera). Agricultural Experimental Station, Technical Bulletin 150, Oregon State University Press, Cor-

vallis, Oregon.

J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

149

SCIENTIFIC NOTE

Polistes dominulus (Christ) (Hymenoptera: Vespidae:

Polistinae) in British Columbia: first collection records

of an invasive European paper wasp in Canada

CHRISTOPHER J. BORKENT' and ROBERT A. CANNINGS?

Two species of the cosmopolitan genus

Polistes (paper wasps), P. fuscatus

(Fabricius) and P. aurifer Saussure, are

native to British Columbia (Carpenter

1996), although some entomologists con-

sider P. aurifer a subspecies of P. fuscatus

(Kenner 2002). These wasps are frequently

confused with yellowjacket species

(Vespinae) but are easily distinguished by

their thread waist, their habit of trailing

their legs in flight, and their nests of ex-

posed cells. They frequently nest on man-

made structures.

The European paper wasp, P. dominu-

lus (Christ) (Fig. 1), native to Europe, Asia

and North Africa, has been introduced into

the USA, Australia and Chile (Carpenter

1996). It was first recorded in the USA

from Massachusetts in the late 1970s

(Eickwort 1978) and its range has since

expanded south and west, covering most of

the northeastern states (Judd and Carpenter

1996, Pickett and Wenzel 2000, Gamboa et

al. 2004, Johnson and Starks 2004). It has

also moved north to Kingston (sighted in

2002) and Sandfield (2004), Ontario (H.

Goulet, Agriculture and Agri-food Canada,

pers. comm.), but apparently no specimens

have been collected in eastern Canada.

Polistes dominulus has recently appeared

in the western USA from Washington to

California and east to Colorado (Landolt

and Antonelli 1999, Pickett 2003). It is not

clear if these populations are the result of

new introductions, possibly from Asia, or

of a western expansion of eastern introduc-

tions (Johnson and Starks 2004).

In British Columbia, P. dominulus was

first recorded in late August 2003, when D.

Manastryski (3808 Rowland Dr. Victoria,

BC) photographed a nest (identified by H.

Goulet) in Saanich. No specimens were

collected, but the photograph was _ pub-

lished on the back cover of the Entomo-

logical Society of Canada 2003 meeting

program. On 5 September 2004, while

walking along the shore of Shuswap Lake

in Salmon Arm, the first author found a

pre-hibernation cluster of about 25 unusual

wasps under an overhang on a wooden

signpost. One was collected and identified

as P. dominulus. Art Borkent (Royal BC

Museum, Victoria, BC) collected 10 wasps

from the same cluster on 20 September

2004. There was no nest or nest-building

activity; this late-season aggregation be-

haviour has been previously reported for

the species (Landolt and Antonelli 1999).

On 30 September 2004, a P. dominulus

nest was collected from a nail protruding

from the eaves of a house in Saanich, BC.

The nest had three female wasps on its

surface (Fig. 1) and 17 between the eaves

and the back of the nest. The wasps may

have congregated for warmth; the tempera-

ture was 7 °C (2130 PDT). The nest held

206 cells, six of which contained larvae in

various stages of development. A few

other cells were less than a third filled with

nectar. This cell number falls well within

the range documented for the species by

Pickett and Wenzel (2000). None of the

specimens collected at either site showed

signs of Strepsiptera parasitism. Voucher

specimens from both localities are depos-

ited at the Royal BC Museum, Victoria,

BC, and the Canadian National Collection

of Insects, Ottawa, Ontario.

Polistes dominulus is_ distinguished

from the native P. aurifer and P. fuscatus

Corresponding author: 2396 Estevan Ave., Victoria, BC, V8R 2S5; email: cborkent@alumni.uvic.ca

Royal BC Museum, 675 Belleville St., Victoria, BC, V8W 9W2

150 J. ENTOMOL. Soc. BRIT. COLUMBIA 101, DECEMBER 2004

by the yellow patterns on the thorax (Fig.

2). Polistes dominulus individuals are usu-

ally the size of yellowjacket wasps, mak-

ing them smaller than native species.

Although P. dominulus is clearly ex-

panding its range, the effect of this inva-

sion on native species is not as easily de-

termined (Pickett and Wenzel 2000, John-

son and Starks 2004). The recent appear-

ance of P. dominulus in BC provides an

opportunity to measure its effect on native

crease in abundance within its new BC

range, resulting in many more observations

in and around human dwellings, where it

prefers to nest.

‘We thank D. Manastryski, A. Borkent

and H. Goulet for their help in collection

and discussion of P. dominulus. The manu-

script was improved by comments from J.

Carpenter and an anonymous reviewer.

This study was supported in part by funds

from the Royal BC Museum.

me oe

Polistes populations. Probably it will in-

‘ sat be 2 a ‘i

: i # wo: Sete: i hy he

“aN b. =. ao,

at a nest in Saanich, BC, 30 September 2004.

Figure 1. Females of Polistes dominulus

Reset eas

Figure 2. Diagrammatic representation of the thorax of Polistes aurifer or P. fuscatus (left)

and P. dominulus (right), showing differences in size and markings (white areas = yellow).

Gray areas represent wings. Scale line = 1 mm.

REFERENCES

Eickwort, G.C. 1978. Polistes dominulus discovered near Boston. Polistine Information Bulletin Newslet-

ter.

Gamboa, G.J., M.A. Noble, M.C. Thom, J.L. Togal, R. Srinivasan and B.D. Murphy. 2004. The compara-

tive biology of two sympatric paper wasps in Michigan, the native Polistes fuscatus and the invasive

Polistes dominulus (Hymenoptera, Vespidae). Insectes Sociaux 51:153-157.

Johnson, R.N. and P.T. Starks. 2004. A surprising level of genetic diversity in an invasive wasp: Polistes

dominulus in the northeastern United States. Annals of the Entomological Society of America 97: 732-

pie

Judd, T.M. and J.M. Carpenter. 1996. Polistes dominulus (Hymenoptera: Vespidae) found in Michigan.

Great Lakes Entomologist 29: 45-46.

Kenner, R. 2002. Stvlops shannoni (Stylopidae, Strepsiptera): A new species for Canada, with comments

on Xenos peckii. Journal of the Entomological Society of British Columbia 99: 99-102.

Landolt, P.J. and A. Antonelli. 1999. The Paper wasp Polistes dominulus (Christ) (Hymenoptera: Vespi-

dae) in the state of Washington. Pan-Pacific Entomologist 75: 58-59.

Pickett, K.M. 2003. Evolution of transitional forms: behavior, colony dynamics, and phylogenetics of

social wasps (Hymenoptera: Vespidae). Ph.D. dissertation, Ohio State University, Columbus, Ohio.

Pickett, K.M. and J.W. Wenzel. 2000. High productivity in haplometrotic colonies of the introduced Paper

wasp Polistes dominulus (Hymenoptera: Vespidae; Polistinae). Journal of the New York Entomologi-

cal Society 108: 314-325.

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MITHSONIAN INSTITUTION LIBRARIE

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Volume 101 Issued December 2004 ISSN #0071-0733 |

Directors of the Entomological Society of British Columbia, 2004-2005

| Gary J.R. Judd and Mark G.T. Gardiner. Simultaneous disruption of pheromone communication and mating in

Cydia pomonella, Choristoneura rosaceana and Pandemis limitata Lepidoptera:Tortricidae) using Isomate-

CM/LR in apple orchards

Heather L. McBrien and Gary J.R. Judd. Emergence of overwintered larvae of eye-spotted bud moth, Spilonota ocel-

lana (Lepidoptera: Tortricidae) in relation to temperature and apple tree phenology at Summerland, British Colum-

Gary J.R. Judd, Mark G.T. Gardiner and Howard M.A. Thistlewood. Seasonal variation in recapture of mass-reared

sterile codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae): implications for control by sterile

insect technique in British Columbia

A.L. Knight and D.M. Light. Use of Ethyl and Propyl (£,Z)-2,4-decadienoates in Codling Moth Management: Improved

Monitoring in Bartlett Pear with High Dose Lures

| A.L. Knight and D.M. Light. Use of Ethyl] (£, Z)-2,4-decadienoate in Codling Moth Management: Stimulation of Ovi-

position

A.L. Knight and D.M. Light. Use of Ethyl (£,Z)-2,4-decadienoate in Codling Moth Management: Kairomone Species

Specificity

A.L. Knight. Managing Codling Moth (Lepidoptera: Tortricidae) with an Internal Grid of Either Aerosol Puffers or

Dispenser Clusters Plus Border Applications of Individual Dispensers

| A.L. Knight and T.E. Larsen. Improved Deposition and Performance of a Microencapsulated Sex Pheromone Formula-

tion for Codling Moth (Lepidoptera: Tortricidae) with a Low Volume Application

J.E. Cossentine and L.B.M. Jensen. Persistence of a commercial codling moth granulovirus product on apple fruit and

foliage

| R.F. Smith, J.E. Cossentine, S.M. Rigby and C.S. Sheffield. Species of ground beetle (Coleoptera: Carabidae) in or-

ganic apple orchards of British Columbia

David R. Horton. Phenology of emergence from artificial overwintering shelters by some predatory arthropods common

in pear orchards of the Pacific Northwest 101-108

Kevin J. Dodds and Darrell W. Ross. Douglas-fir beetle lipid levels in relation to tree physical characteristics

109-116

John H. Borden, Deepa S. Pureswaran and Lisa M. Poirier. Evaluation of two repellent semiochemicals for disruption

of attack by the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae) 117-124

G.G.E. Scudder. Heteroptera (Hemiptera: Prosorrhyncha) New to Canada. Part 2 125-130

John P. Simaika and Robert A. Cannings. Lestes disjunctus Selys and L. forcipatus Rambur (Odonata: Lestidae): Some

Solutions for Identification 131-140

SCIENTIFIC NOTES

R.S. Vernon. A ground-based pheromone trap for monitoring Agriotes lineatus and A. obscurus (Coleoptera: Elateridae)

141-142

Sarah L. Bates and John H. Borden. Parasitoids of Leptoglossus occidentalis Heidemann (Heteroptera: Coreidae) in British

Columbia 143-144

Darrell W. Ross, Gary E. Daterman and A. Steven Munson. Evaluation of the antiaggregation pheromone, 3-

methylcyclohex-2-en-1-one (MCH), to protect live spruce from spruce beetle (Coleoptera: Scolytidae) infestation

in southern Utah 145-146

R.D. Kenner and K.M. Needham. New waterboatmen records for Western Canada (Hemiptera: Corixidae) 147-148

Christopher J. Borkent and Robert A. Cannings. Polistes dominulus (Christ) (Hymenoptera: Vespidae: Polistinae) in

British Columbia: first collection records of an invasive European paper wasp in Canada 149-150

| NOTICE TO CONTRIBUTORS