J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Journal of the

Entomological Society of British Columbia

Volume 108 Issued December 2011 ISSN #0071-0733

Directors of the Entomological Society of British Columbia, 2011-2012... 2

L. Camelo, T.B. Adams, P.J. Landolt, R.S. Zack and C. Smithhisler. Seasonal patterns

of capture of Helicoverpa zea (Boddie) and Heliothis phloxiphaga (Grote and

Robinson) (Lepidoptera: Noctuidae) in pheromone traps in Washington State.......... 3

E. Miliczky and D.R. Horton. Occurrence of the Western Flower Thrips, Frankliniella

occidentalis, and potential predators on host plants in near-orchard habitats of

Washington and Oregon (Thysanoptera: Thripidae).............cccccccceessseeceeessteeeeeesnsees |

G.G.E. Scudder, L.M. Humble and T. Loh. Drymus brunneus (Sahlberg) (Hemiptera:

Rhyparochromidae): a seed bug introduced into North America................cccccceeees 29

A.G. Wheeler, Jr. and E.R. Hoebeke. Asciodema obsoleta (Hemiptera: Miridae): New

Records for British Columbia and First U.S. Record of an Adventive Plant Bug of

Scotch Broom (Cyisus sconarius; Fabaceae) j.2cceceeesccetersesns ceccevieextorcenshcaracecernse> 34

NOTES

W.G. van Herk and R.S. Vernon. Mortality of Metarhizium anisopliae infected

wireworms (Coleoptera: Elateridae) and feeding on wheat seedlings is affected by

VAC MVE Wiel O Ils sasentaststacaadsesseaastennnatacnaavoncats iecssnnee ren iat teteaea aes Mia teat atct anatase coe ae 38

ANNUAL GENERAL MEETING ABSTRACTS

Symposium Abstracts: Invasion Biology! Douglas College, New Westminster, B.C.,

RCs Ta OU cance gt ae AE th a eee ce recente tan reat ocd ye cham ene stee 42

Entomological Society of British Columbia Annual General Meeting Presentation

Abstracts. University of the Fraser Valley, Abbotsford, B.C., Oct. 14, 2011............ 44

NOTICE TO THE CONTRIBUTORS. ....00.......ecccccceceeeeeeteeeees Inside Back Cover

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

DIRECTORS OF THE ENTOMOLOGICAL SOCIETY

OF BRITISH COLUMBIA FOR 2011-2012

President:

Ward Strong

B.C. Ministry of Forests, Lands and Natural Resource Operations

President-Elect:

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Agriculture and Agri-Foods Canada, Summerland

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Douglas College

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B.C. Ministry of Forests, Lands and Natural Resource Operations

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B.C. Ministry of Forests, Lands and Natural Resource Operations

Directors, first term:

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Directors, second term:

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University of Northern British Columbia Lorraine Maclauchlan, Robert Cannings, Steve

huber@unbc.ca Periman, Lee Humble, Rob McGregor,

Robert Lalonde, Hugh Barclay

Assistant Editor: Ward Strong

Technical Editor: Tanya Stemberger Editors Emeritus: Peter and Elspeth Belton

J. ENTOMOL. SOc. BRIT. COLUMBIA 108, DECEMBER 2011

Seasonal patterns of capture of Helicoverpa zea (Boddie) and

Heliothis phloxiphaga (Grote and Robinson) (Lepidoptera:

Noctuidae) in pheromone traps in Washington State.

L. CAMELO|, T. B. ADAMS P. J. LANDOLT?, R. S. ZACK‘, and C.

SMITHHISLER

ABSTRACT

In each of the 6 years of this study in south central Washington state, male corn earworm

moths, Helicoverpa zea (Boddie), first appeared in pheromone traps in late May to mid June,

and thereafter were present nearly continuously until mid to late October. Maximum numbers

of male corn earworm moths captured in pheromone traps occurred in August and early

September. Male Heliothis phloxiphaga (Grote and Robinson) moths first appeared in traps

baited with corn earworm pheromone and conspecific pheromone in April, and were generally

present throughout the season until mid to late September. In some years, two peaks of trap

capture of H. phloxiphaga males was suggestive of two generations per season, with one flight

in April and May and the other in July and August. Although both species were caught

primarily in traps baited with their appropriate conspecific pheromone, smaller numbers of

both species were captured in traps baited with the heterospecific pheromone. Heliothis

phloxiphaga captured in corm earworm pheromone traps can be misidentified as corn

earworm, resulting in false positives for corm earworm in commercial sweet corn or

overestimates of corn earworm populations.

Key Words: Seasonal phenology, Helicoverpa zea, Heliothis phloxiphaga, corn earworm,

trapping, pheromone

INTRODUCTION

Helicoverpa zea (Boddie), the corn

earworm (CEW), is a pest of many

agricultural crops, particularly corn, tomato,

and cotton (Metcalf and Metcalf 1993). The

moth is monitored in cropping systems with a

four component sex pheromone (Klun ef al.

1980). In the irrigated farming areas of south

central Washington, the corn earworm is the

key pest of sweet corn, and numerous

pesticide applications are required per season

to control it. Heliothis phloxiphaga (Grote and

Robinson) is generally not a pest but is

important as a non-target insect that is

sometimes captured in corn earworm

pheromone traps (Adams 2001, Hoffman et al.

1991). Heliothis phloxiphaga males respond

to the corn earworm pheromone, due to the

overlapping chemistries of pheromones of

these two species (Kaae et al. 1973, Klun ef

al. 1980, Raina et al. 1986). Because of their

' 2700 Seminis Inc., Camino del Sol, Oxnard, CA 93030

overlapping size and coloration, H.

phloxiphaga in CEW pheromone traps may be

wrongly identified, giving false positive

indications for CEW and potentially leading to

unnecessary pesticide applications (Adams

2001, Hoffman et a/. 1991). Photographs of

the adult stage of both species are figured by

Covell (1984), Powell and Opler (2010), and

on the Noctuoidea of Canada Website

(Troubridge and Lafontaine 2011).

Monitoring of the male corm earworm

moth flight with pheromone traps provides

information to growers and field scouts that is

used to make pest management decisions.

Growers of sweet corn in Washington use the

traps to indicate the onset of arrival of corm

earworm moths, and the need to begin a spray

program. In this area, the corn earworm has

one to three generations per year (Mayer ef al.

1987), while H. phloxiphaga may be

* Oregon State Department of Agriculture, 635 Capitol St. NE, Salem, OR, USA 97302

3 Corresponding author. peter.landolt@ars.usda.gov

4 Department of Entomology, Washington State University, Pullman, WA 99164

univoltine (Piper and Mulford 1984). Sweet

com is first planted in May in eastern

Washington, becomes susceptible to attack by

the corn earworm in mid July, and is grown by

staggered planting dates into October.

Growers need to know when to expect corn

earworm moth flight, and when to be

concerned with distinguishing corn earworm

from H. phloxiphaga moths in corn earworm

pheromone traps. Seasonal patterns of corm

earworm captures in traps have been

determined for other geographic and climactic

areas (Parajulee et al. 2004, Weber and Ferro

1991) but these reports may not be applicable

to irrigated agriculture of Washington.

J. ENTOMOL. SOc. BRIT. COLUMBIA 108, DECEMBER 2011

The primary objective of this study was to

determine the seasonal occurrences of adult H.

zea and H. phloxiphaga in central Washington.

We determined seasonal patterns of moths

present as indicated by captures of moths in

pheromone-baited traps. In addition, we note

responses of the two species to their

conspecific and heterospecific sex

pheromones. Differences and similarities in

the seasonal patterns of the two species should

help with interpretation of trap catch data and

reduce errors caused by the capture of both

species in traps used for corn earworm pest

management programs.

MATERIALS AND METHODS

Trapping studies were conducted in 1999

to 2004 in south central Washington. The

multicolored (white bucket with yellow cone

and green lid) Universal Moth Trap (Great

Lakes IPM, Vestaburg, MI) was used, with a

6.4 cm2 piece of Vaportape™ (Hercon

Environmental, Emigsville, PA) stapled to the

inside wall of the trap bucket to kill captured

insects. In all cases, traps were checked and

captured insects removed each week, and

Vaportape™ and lures were replaced every 4

weeks.

Corn earworm lures were the pheromone

identified by Klun et al. (1980) consisting of

86.7% (Z)-ll-hexadecenal, 3.3% (Z)-9-

hexadecenal, 1.7% (Z)-7-hexadecenal, and

8.3% hexadecanal in a total pheromone load

of 1.0 mg per septum, following the methods

of Halfhill and McDunough (1985).

Pheromone lures for H. phloxiphaga (Raina et

al. 1986) were 92% (Z)-11-hexadecenal, 0.4%

(Z)-9-hexadecenal, 4.8% hexadecanal, and

2.8% (Z)-11-hexadecen-l-ol in a total

pheromone load of 1.0 mg per septum.

Pheromone was loaded into red rubber septa

(West Co., Lyonville, PA ) that had been pre-

extracted twice with methylene chloride in a

tumbler. Pheromone was applied to septa as a

solution in hexane, at a dosage of 200

microliters per septum. Chemicals were

purchased from Farchan Chemicals (Atlanta,

GA) and Aldrich Chemical Co. (Milwaukee,

WI), and all chemicals were 95% or greater

purity. The aldehydic pheromone compounds

were purified by elution through a silica gel

column with 5% ether in hexane. Pheromone

dispensers were stored in glass vials in a

freezer until placed in traps in the field.

Pheromone lures were placed in the plastic

baskets provided at the center of the inside of

the tops of the traps

Traps were set up early in the season near

fields to be planted to corn, and were

maintained until the moth flights ended in late

autumn. Traps were either hung on fences or

from stakes put into the ground, at a height of

0.7 to 1.0 m. Traps were checked each week,

and Vaportape™ and pheromone lures were

replaced each month. Moths in traps were

placed in labeled Ziploc® plastic bags for

transport to the laboratory, where moths were

sorted, identified, and counted. Voucher

specimens are deposited in the James

Entomological Collection, Department of

Entomology, Washington State University,

Pullman, WA.

Season-long monitoring of CEW with

pheromone traps. Corn earworm moths were

trapped throughout the seasons of 1999-2004,

with from 4 to 9 trap sites used per season

(Table 1). One trap baited with corn earworm

pheromone was placed at each site. Trapping

sites were selected based on abundant acreage

of commercial sweet com to be planted

nearby. At the end of the season, traps were

recovered from the field, washed with hot

soapy water, rinsed with tap water, and

exposed outside to sun and open air in wooden

bins for a minimum of 30 days before indoor

winter storage, to reduce risk of long term

contamination of the trap by pheromone.

Season-long monitoring of H.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

phloxiphaga with pheromone traps.

Heliothis phloxiphaga moths were monitored

with traps baited with H. phloxiphaga

pheromone, during 1999-2001. Trapping sites,

trapping dates, and trap maintenance were the

same as those indicated above for corn

earworm pheromone traps during the same

years (Table 1). One trap baited with 4H.

phloxiphaga pheromone was placed at each

site, more than 90 meters from the corn

earworm pheromone trap.

We also report H. phloxiphaga moths

captured in traps baited with CEW pheromone

from 1999-2004, and CEW moths captured in

traps baited with H. phloxiphaga pheromone,

from 1999-2001. Statistical comparisons were

made of numbers of CEW and H. phloxiphaga

moths trapped in response to conspecific

versus heterospecific sex pheromone lures,

using a paired t-test.

Table 1.

Dates and lures for season long monitoring of corn earworm.

No. of ; d Pheromones

Year Start Date Sites Site Locations ey

Yakima Co., Mabton & CEW

1999 paneny ? Toppenish Benton Co., Prosser H. phloxiphaga

CEW

2000 20 April ) Grant Co., Mattawa H. phloxiphaga

; Grant Co., Moses L. Franklin Co., CEW

200) popu) : Pasco H. phloxiphaga

002 25 March 4 Yakima Co., Wapato, Granger, CEW

Donald, Toppenish

3003 29 March Yakima Co., Toppenish & Moxee CEW

Benton Co., Prosser

3004 yl Yakima Co., Toppenish & Moxee CEW

Benton Co., Prosser

RESULTS

Generally, first male corn earworm moths

were captured in late May, and males were

present continuously through the summer into

October (Figure 1). In all years, maximum

numbers of male moths were captured in

August. However, in 2002 and 2003, a smaller

peak of activity was apparent in June.

Numbers of moths per trap per week varied

widely from year to year, with a maximum of

over 250 per trap per week in 2002, but under

70 moths per trap per week in 1999, 2000, and

2003.

For 1999-2001, data for H. phloxiphaga

are from traps baited with conspecific

pheromone, and for 2002-2004, data for H.

phloxiphaga are from traps baited with CEW

pheromone. Generally, male H. phloxiphaga

moths were first captured in pheromone traps

in April (Figure 2). In 1999 and 2000, traps

were not placed in the field early enough to

determine the onset of H. phloxiphaga flight

and males were captured during the first week

of the study. In all 6 years, there were two

separate periods of flight activity of male H.

Phloxiphaga. The first period was in late April

to early June, and the second period was mid

July to late August. Numbers of moths trapped

varied greatly from year to year, with a

maximum of over 24 male moths per trap per

week in 2004, and a maximum of fewer than 5

moths per week in 1999.

Traps baited with CEW pheromone

captured primarily CEW moths, and traps

baited with H. phloxiphaga pheromone

captured primarily H. phloxiphaga (Table 2).

In 1999, 2000, and 2001, when the

pheromones of both CEW and H. phloxiphaga

were maintained throughout the season, CEW

moths were captured primarily in traps baited

with the CEW pheromone, with relatively few

captured in traps baited with the H.

phloxiphaga pheromone. Numbers of male H.

phloxiphaga captured were numerically but

not significantly greater in traps baited with

J. ENTOMOL. Soc. BRIT. COLUMBIA 108, DECEMBER 2011

the H. phloxiphaga pheromone compared to

traps baited with the CEW pheromone

(Table 2).

DISCUSSION

The primary objective of this study was to

characterize the seasonal patterns of captures

of CEW and H. phloxiphaga moths in traps in

southcentral Washington as an indicator of

adult moth presence in corn fields. Particular

aspects of moth seasonal patterns that are

potentially of interest include the onset of

moth flight in the spring and cessation in

autumn, peak activity periods, and numbers of

generation per year. In this case, we are also

eT ET re ere SE

280

210

148

CORN EARWORM MALES/TRAP/WEEK

G ,* + i jy i 4

DF OSS 44 ARE M2 MOH WI 8G TT ME BS VIB YI WS VS WIS WL

1993 DATE

CORN EARWORM MALES/TRAP/WEEK

5 oft OA

ak wv aNG

dg = ba.

0 bbb eet ee

SH? SGt BAS B68 GAZ SHE ENO ES NF HR BH BAB Wt ONS BUG wars rH?

2000 DATE

CORN EARWORM MALES! TRAP/WEEK

SHS BRB aN?

2001 DATE

SOO tS SAB BHD RSS ERD HANTS 828

CORN EARWORM MALES/T RAP/WEEK CORN EARWORM MALES/TRAP/WEEK

CORN EARWORM MALES/TRAP/WEEK

interested in determining periods of risk of

misidentifying H. phloxiphaga as CEW, in

relation to CEW pest management. Although

numbers of CEW moths captured in

pheromone traps varied greatly from year to

year, the cessation, termination, and peak

periods of moth activity were similar

throughout this 6 year period. The period

during which corn earworm moths were active

broadly encompasses the entire period during

350

280

210

140

70 OF

BB WV? 4 419 33 $87 5B

B83 VR TM WG SB BAT GS 99 188 1DIT 1033

2002 DATE

Mig SOR AT BGS 53 SUH GE EKO ATH RE ONT oKE TOR 1008

2003 DATE

350

280

2168

140

a Ly

ChE FQ WE 20 BIG BLE 910 OMS 10GB 10

2004 DATE

M2 Bh aM 3a3 8? 2 wa

Figure 1. Mean (+ SE) numbers of male corn earworm moths captured per week per trap, in traps

baited with corn earworm pheromone, for 1999, 2000, 2001, 2002, 2003, and 2004.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

H. PHLOXIPHAGA MALES/TRAPAWEEK

Mi WS) Aid BIA TIZARD OFZD_ 10/43. TORT

4999 DATE

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2000 DATE

H. PHLOXIPHAGA MALES/TRAP/WEEK

H. PHLOXIPHAGA MALES/TRAPIWEEK

B35 329 SZ ABB SIS SIH BIZ 8G TH 723 HE BO OOS BHT IU 1OsTS 1023

2001 DATE

p 4

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2002 DATE

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2003 DATE

H. PHLOXIPHAGA MALES/TRAP/WEEK

WR NSE 48 ws BW B21 GH ENB MR TG TF BIS BAZ IO 2A OM 12

2004 DATE

Figure 2. Mean (t SEM) numbers of male H. phloxiphaga moths captured per week per trap, in traps

baited with H. phloxiphaga pheromone (1999, 2000 and 2001) or corn earworm pheromone (2002,

2003, 2004).

which corn is grown in this same area. Corn is

normally first planted after last frost, in mid to

late May, and staggered plantings and

harvesting continue into early October.

However, corn is a suitable oviposition site for

CEW beginning with the silking stage, which

starts in late June. Earlier in the season, CEW

moths might be infesting alternate host plants,

possibly weed and wild flower species

(Hardwick 1965, 1996; Neunzig 1963;

Robinson et al. 2002). It is assumed that the

end of moth flight in autumn may occur

primarily as a result of decreasing

temperatures making moth flight impossible.

In contrast to evidence for CEW migrating

from south to north (Hartstack et al. 1982;

Westbrook et al. 1997), there is no

documentation of north to south migration. If

such a migration occurs, it could explain in

part the disappearance of the moth in early

autumn in south central Washington.

Mayer et al. (1987) reported 1-3

generations of CEW per year in Washington.

Our data show nearly continuous moth

activity for 5 months, from late May into mid

to late October, without evidence of distinct

generations. Corn earworm may overwinter in

the southern Columbia Basin of Washington,

as pupae in soil (Eichman 1940, Klostermeyer

1968), first emerging in May. The

interpretation of trap catch data may be

complicated by immigration of CEW

populations from the southwestern U. S. In

other areas of North America, CEW moths

migrate (Hartstack et al. 1982; Hendrix et al.

1987; Lingren et al. 1993, 1994; Westbrook et

al. 1997). Strong increases in numbers of male

CEW moths in pheromone traps in August

may have been due to reproduction by earlier

emerging moths, and/or migrating moths that

arrive in south central Washington with

infrequent weather fronts.

The seasonal activity and abundance of the

com earworm moth varies geographically,

probably in response to climactic factors and

their impact on migration, reproduction, and

other behaviors, as well as regional makeup

and abundance of crops and crop planting and

harvest cycles. The amplitudes of the seasonal

patterns of catches of CEW moths in

pheromone traps in south central Washington

were small compared to that observed in

Texas by Parajulee et al. (2004). Captures of

moths in pheromone traps often began in April

in Texas, compared to May in Washington,

and ended in October as it did in our study in

Washington. In Mississippi, CEW males were

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

captured in pheromone traps sporadically from

early June to the end of September (Hayes

1991). In Massachusetts, CEW moth flight

appears to begin much later than in south

central Washington despite a similar latitude.

Weber and Ferro (1991) captured CEW moths

in pheromone traps in Massachusetts from

early July into early September, which is a

seasonal activity period that is nearly 2

months shorter than seen in our study.

Piper and Mulford (1984) reported that H.

Dhloxiphaga was univoltine in Washington.

The data presented here indicate consistently

over the 6 years that there were two periods of

increased catches of moths in traps, indicating

possibly two generations per year. The

apparent two maxima of activity indicated by

pheromone traps suggests that a first adult

generation occurred in April/May and a

second generation in July/August. However,

Hoffman et al. (1991) did not see more than

one peak of captures of H. phloxiphaga in

corn earworm pheromone traps in California,

although adult activity was noted over a

period of 6 months, from February to

September. Certainly, multiple generations of

a moth species can occur within a season

Table 2

Mean (+SE) numbers of male corn earworm and H. phloxiphaga moths captured per season per trap

baited with corn earworm and H. phloxiphaga sex pheromones.

Moth species Corn earworm

captured pheromone

1999

Corn earworm 218.3 + 64.2a

H. phloxiphaga 6.9+2.4a

2000

Corn earworm 427.6 + 52.3a

H. phloxiphaga 25.2 + 6.4a

2001

Corn earworm

H. phloxiphaga

415.8 + 144.0a

22 ea

H. phloxiphaga -

pheromone

14+1.1b 9

12.4+3.9a 9

3.8 +'1.0b 5

44.2+ 10.9a 5

2.) + 0.9b 4

16.0+5.8a 4

Means within a row followed by the same letter are not significantly different by a paired t-test at P <

0.05.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

without the appearance of distinct separated

periods of flight indicated in pheromone traps.

In all six years of our study, the first flight

of H. phloxiphaga began about one month

before the first catches of CEW moths in

traps, and captures of H. phloxiphaga moths

ended about one month before the last

captures of CEW moths. Peak numbers of

possible second flight H. phloxiphaga

populations overlapped somewhat with peak

numbers of CEW in early August, although

the numbers of H. phloxiphaga in H.

Dhloxiphaga pheromone traps were

considerably less than CEW moths trapped

with corn earworm pheromone. It appears then

that CEW monitoring traps in May might

easily provide misleading information from

the capture of H. phloxiphaga misidentified as

CEW, but before the expected appearance of

CEW. Also, in August, H. phloxiphaga

captured in CEW pheromone traps may inflate

counts of CEW trap catch, if misidentified.

However, those numbers would usually be

minor in relation to the numbers of CEW

moths trapped at that time. It is most

important to positively identify the two

species early in the season, and again in late

summer when both are present, but in

situations where corn earworm populations are

expected to be low.

Although the chemistry of the H.

phloxiphaga sex pheromone overlaps with that

of the CEW pheromone, H. phloxiphaga

responses to the CEW lure are not consistently

a problem with CEW monitoring programs in

North America. Weber and Ferro (1991) found

5 non-target species of noctuids captured in

CEW monitoring traps in Massachusetts, but

did not indicate the trapping of ok

phloxiphaga. Chapin et al. (1997) reported

non-target moths captured in corn earworm

traps, but captured only one H. phloxiphaga

moth compared to over 25,000 CEW.

However, in eastern Washington, H.

phloxiphaga is consistently present throughout

much of the corn growing season and is

routinely captured in corn earworm

pheromone traps (Adams 2001), and Hoffman

et al. (1991) trapped it in sweet corn fields

throughout California. Growers can reduce

costs and pesticide used by distinguishing the

two species when captured in com earworm

traps, and by recognizing that corm earworm

are unlikely to be present before late May.

ACKNOWLEDGEMENTS

Assistance with lures, traps, and moths was

provided by J. Brumley, P. Chapman, J.

Dedlow, D. Larson, D. Lovelace, and C.

Martin. We thank L. Anderson, A. Bassani, R.

Earl, L. Elder, R. Halvorson, C. Martin, R.

Martinez, J. Rice, H. Sealock, P. Smith and B.

Thorington for access to their fields. Del

Monte Corporation, Toppenish, WA provided

a vehicle for use in this study. This work was

supported in part by funding from the

Columbia Basin Vegetable Processors

Association, the America Farmland Trust

Foundation, the Environmental Protection

Agency, and a USDA, Western Region IPM

grant.

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Chapin, J. B., D. R. Ganaway, B. R. Leonard, S. Micinski, E. Burris, and J. B. Graves. 1997. Species composition

of Heliothinae captured in cone traps baited with synthetic bollworm or tobacco budworm pheromones.

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Covell, C. V., Jr. 1984. A Field Guide to the Moths of Eastern North America. Houghton-Mifflin Co., Boston. 496

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Eichman, R. D. 1940. Corn earworm hibernates in Washington State.

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J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Occurrence of the Western Flower Thrips, Frankliniella

occidentalis, and potential predators on host plants in near-

orchard habitats of Washington and Oregon (Thysanoptera:

Thripidae)

EUGENE MILICZKY!”, and DAVID R. HORTON!

ABSTRACT

One hundred thirty species of native and introduced plants growing in uncultivated land

adjacent to apple and pear orchards of central Washington and northern Oregon were sampled

for the presence of the western flower thrips (WFT) Frankliniella occidentalis (Pergande,

1895) and potential thrips predators. Plants were sampled primarily while in flower. Flowering

hosts for WFT were available from late-March to late-October. Adult WFT occurred on 119

plant species and presumed WFT larvae were present on 108 of 119 species. Maximum

observed WFT density on several plant species exceeded 100 individuals (adults and larvae)

per gram dry weight of plant material. The most abundant predator was Orius tristicolor

(White, 1879) (Heteroptera: Anthocoridae). It was collected on 64 plant species, all of which

were hosts for WFT. The second most abundant predators were spiders (Araneae). Small

spider immatures (first and second instars) of several species were common on certain host

plants, and are likely to feed on WFT.

Key Words: Frankliniella occidentalis, western flower thrips, host plants, predators, Orius

tristicolor, Araneae, spiders.

INTRODUCTION

The western flower thrips (WFT)

Frankliniella occidentalis (Pergande, 1895),

was originally distributed throughout western

North America (Kirk and Terry 2003). In the

past 30 years WFT has spread to much of the

rest of North America and now also occurs

throughout Europe and parts of North Africa

(Kirk and Terry 2003). It is a pest in both the

field and the greenhouse, attacks a large

number of crops, and causes damage by

feeding, oviposition, and most importantly,

transmission of Tospoviruses (Reitz 2009).

WET is an important secondary pest of certain

apple varieties in the Pacific Northwest,

producing a pale, cosmetic blemish known as

a pansy spot that forms around the site of

oviposition (Venables 1925; Madsen and Jack

1966). Although the damage is superficial,

affected fruit may be downgraded at harvest

(Madsen and Jack 1966; Terry 1991). Control

of WFT on apple can be challenging because

it occurs on trees primarily when pollinators,

especially honeybees, Apis mellifera

Linnaeus, 1758, are active in the orchard

canopy. It has also been difficult to determine

when, during fruit formation, damage-causing

Oviposition occurs and, consequently, when

control measures are most needed (Cockfield

et al. 2007).

Host plant utilization by WFT is very

broad. Bryan and Smith (1956) found it on

139 plant species (representing 45 families) in

California, which is within the pest’s original

geographic range. In areas to which it has

spread, host plant utilization is also broad, and

in Hawaii it was found on 48 plant species on

the island of Maui (Yudin ef al. 1986).

Chellemi et al. (1994) found it on 24 of 37

plant species surveyed in Florida within a

decade after its first detection. In a study done

barely ten years after the insect was first

reported all 49 plant species sampled in

Turkey harbored WFT (Atakan and Uygur

2005). In Chile, where it has become a serious

' Yakima Agricultural Research Laboratory, United States Department of Agriculture — Agricultural Research

Service, 5230 Konnowac Pass Road, Wapato, WA 98951

Corresponding author: gene,miliczky@ars.usda,gov

agricultural pest, WFT occurred on 50 of 55

plant species and appears to have supplanted a

native species of Frankliniella as the most

common thrips species (Ripa et al. 2009).

A number of predators are known to attack

WFT (Sabelis and Van Rijn 1997). Few of the

studies that have reported on WFT’s

occurrence on non-crop plant species have

also reported on the presence of predator

species. Northfield et al. (2008) studied the

population dynamics of WFT on seven

uncultivated host plants and also reported on

the occurrence of the important thrips predator

Orius insidiosus (Say, 1832) (Heteroptera:

Anthocoridae). Tommasini (2004) monitored

Orius populations on known host plants of

WEFT in Italy and found that several species of

Orius commonly occurred at high densities on

J. ENTOMOL. SOc. BRIT. COLUMBIA 108, DECEMBER 2011

a number of these host plants, apparently in

association with WFT.

In this study, we surveyed native and

introduced plant species in fruit-growing

regions of central Washington and northern

Oregon where WFT is a secondary pest of

certain apple varieties. Our objectives were to

1) gain an understanding of WFT utilization of

non-cultivated host plants typical of near-

orchard habitats in the study areas, 2) develop

a better understanding of WFT phenology

across the season, and 3) improve our

understanding of known and potential WFT

predators occurring on these non-cultivated

host plants, with emphasis on minute pirate

bugs (Heteroptera: Anthocoridae) and spiders

(Araneae).

MATERIALS AND METHODS

Study Sites. This study was conducted at

11 sites in Washington State and two sites in

northern Oregon (Table 1). Virtually all

sampling was done in native habitat

immediately adjacent to orchards, generally

within 100 m of an orchard edge; a few plant

species of interest that occurred in the

understory of orchards were also sampled.

Most of the sites were in Yakima County,

Washington, located in the south-central part

of the state. Two sites were near Hood River

in northern Oregon (Table 1).

With one exception, each tract of native

habitat was at least several hectares in area

and adjacent to orchard habitat. The only

exception was a tract comprising a 25 m wide

strip of native vegetation occurring between

an orchard and an irrigation canal. Native

habitat at all Yakima County and the Grant

County locales was sagebrush steppe (Table

1). Sagebrush steppe at Hambleton, Durey,

and Sunset fell within the lithosol zone of

Taylor (1992), and is characterized by thin,

rocky soils and a diverse flora. In mid-May at

these locations we noted 25 or more plant

species in flower simultaneously. Sagebrush

steppe at the remaining Yakima County sites

and the Grant County site fell within the

standard-type zone (Taylor 1992),

characterized by moderately deep soil and

vegetation dominated by grasses and _ tall

sagebrush, Artemisia tridentata Nutt.

(Asteraceae). The Ing, Wells, and Alway sites

consisted of mixed hardwood/coniferous

woodland. Trees included Pinus ponderosa

Dougl. (Pinaceae), Pseudotsuga menziesii

(Mirbel) Franco (Pinaceae), Acer

macrophyllum Pursh (Aceraceae), and

Quercus garryana Dougl. (Fagaceae).

Understories at all three sites consisted of a

variety of shrubs and forbs.

Sampling for thrips and predators. The

Yakima County study sites were visited at

approximately weekly intervals during 2002

from early April to late October. Due to

greater travel distances the Grant County site

was visited bi-weekly, and the Chelan County

and Oregon sites were visited monthly from

April to July. Sampling in 2003 was limited to

selected plant species (see below) at sites in

Yakima County. Durey and Hambleton were

visited weekly from late March to late

October, while the other Yakima County sites

were visited when species of interest were in

flower. During each visit, observations were

made of plants in flower and whether a

species was at early, full, or late bloom. Notes

were also made of species that had recently

passed out of bloom and of those that were

about to come into bloom.

Samples were collected by removing

inflorescences or individual flowers with

scissors or pruning shears and immediately

placing them in 3.8L, self-sealing, plastic

bags. Care was taken when removing flowers

to avoid dislodging insects and spiders. Since

J. ENTOMOL. Soc. BRIT. COLUMBIA 108, DECEMBER 2011

Table 1.

Sampling sites, habitat type at each site, and sampling frequencies.

frequency!

Site Location (county)

Hambleton 3.5 km N Tieton (Yakima)

D 4.5 km NNW Tieton

urey

(Yakima)

Sunset 4.5 km S Tieton (Yakima)

Caren 3 km SSE Union Gap

(Yakima)

Leach 6 km NNE Zillah (Yakima)

Lynch 5.5 km NE Zillah (Yakima)

Hattrup 5 km SSE Moxee (Yakima)

Valicoff oe cane

USDA 18 km ESE Moxee (Yakima)

Knutson 10 km SE Mattawa (Grant)

Alway Peshastin (Chelan)

Ing (Oregon) 2 km SSE Hood River

(Hood River)

Wells (Oregon) : wae feet

Sampling

Habitat 2002 2003

Sagebrush-steppe W W

Sagebrush-steppe W I

Sagebrush-steppe BW --

Mixed hardwoods and conifers M --

|W, weekly; BW, bi-weekly; M, Monthly; I, irregularly.

WFT is primarily associated with flowers,

non-flower plant parts such as leaves and

stems were kept to a minimum in samples

during the bloom periods. Samples taken

outside of the bloom period included primarily

rapidly growing vegetative tissue. Samples

were transported in a cooled ice chest to the

laboratory where they were held in a

refrigerated room until processed, generally

within 24 h. The amount of plant material

collected for a sample varied from species to

species depending upon its abundance at a site

and the nature of its inflorescence. Abundant

species with large or bulky inflorescences

were collected in sufficient quantity to loosely

fill a bag. Smaller quantities were obtained of

less abundant species and those with small,

more difficult to collect flowers. Blooms were

collected from several individual plants per

species at a site to obtain a sample. The

number of individual plants sampled per

species depended upon the density of that

species at the site.

We were interested in each plant species

primarily during its bloom period. A single,

flowering period sample was obtained for

some species, but many were sampled more

than once during bloom. Several species were

sampled weekly while in flower with

additional samples taken during the pre-bloom

and post-bloom periods. The extreme example

was bitterbrush Purshia tridentata (Pursh) DC

(Rosaceae), which was sampled weekly at the

Durey site from 16 April to 28 October 2003,

for a total of 29 sample dates. Most species

were sampled at one or two locations, but

samples from arrowleaf balsamroot

Balsamorhiza sagitatta (Pursh) Nutt.

(Asteraceae), a common, widespread species,

were obtained at nine sites. In 2002, most of

the plant species at each site were sampled on

at least one date. Based on the 2002 findings,

16 species that supported high numbers of

thrips and predators were monitored in 2003.

Extraction of arthropods. Thrips and

predatory arthropods were extracted from

plant material using Berlese funnels. Heat

from 40 watt light bulbs was used to force

arthropods out of the plant material and into

500 ml plastic jars each containing 50 ml of

70% isopropyl alcohol. Samples were held in

the funnels for 24-48 h depending on the

quantity of plant material. This length of time

was sufficient to dry the plant material, which

was then weighed on an electronic balance.

We calculated thrips numbers per gram dry

weight of plant material.

Processing of samples. WFT was the only

thrips identified to species (by comparison

with vouchers). Species other than WFT were

generally few in number (see Results). Larval

thrips were counted but were not identified.

When the adult thrips in a sample were

exclusively WFT we assumed that all larval

thrips were that species. If adults of more than

one species were present the number of larval

WFT was estimated based on the proportion

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

of adult WFT in the sample. If the number of

thrips in a sample appeared to be less than

300, an exact count was made. For samples

that obviously contained a greater number, the

number of thrips was estimated by counting a

subsample (an exception was made for the

maximum density from each plant species,

which was always determined by an exact

count). To obtain estimates from subsamples,

the thrips (in alcohol) were poured into a

plastic Petri dish inscribed on the bottom with

Six Squares each 1 cm x 1 cm in size. The dish

was agitated until the thrips were distributed

approximately uniformly over the bottom of

the dish. The thrips within each square were

counted, the average number per square was

computed, and this average was multiplied by

the area of the dish to obtain an estimate of the

total.

Exact counts were made of all predators.

For minute pirate bugs, Orius spp., the

number of males, females, and each of the five

nymphal instars was determined. Samples

were composed almost entirely of Orius

tristicolor (White, 1879), although scattered

individuals of Orius diespeter Herring, 1966

were likely present in the Peshastin samples

(Lewis et al. 2005). Immature spiders of

several species were common in some

samples. In most cases it was possible to

identify these to species based on our

familiarity with the local fauna. It was also

possible to estimate the nymphal stage of

many of these spiders based on comparison

with reference specimens of known stage.

RESULTS

Host plant characteristics. One hundred

and thirty plant species were sampled,

representing 34 plant families and 101 genera

(Table 2). Ninety-nine species were native to

the study area, while 31 species were

introduced. The Asteraceae was represented

by the most species (32), and the wild

buckwheat genus Eriogonum (Polygonaceae)

was the best represented genus with seven

species. Samples from red clover Trifolium

pratense L., white clover Trifolium repens L.,

and alfalfa Medicago sativa L. (all Fabaceae)

were collected only within orchards. Plant

growth form varied, but perennial forbs were

the most common (62 species) followed by

shrubs (20 species) and annual forbs (16

species).

Host plant utilization by Frankliniella

occidentalis. Adult WFT were extracted from

119 plant species, while thrips larvae were

extracted from 108 of these same 119 species

(Table 2). Plant species that harbored both

adult and larval WFT are assumed to be

reproductive hosts for the insect. Of the 11

species that did not yield WFT, eight were

sampled only once, five have rather small or

inconspicuous flowers, and one blooms early

in the spring. Two of the species that did not

yield WFT, (Lomatium triternatum (Pursh)

Coult. and Rose and Erigeron pumilus Nutt.)

had congeneric species that yielded both adult

WEFT and larval thrips. It is likely that more

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011 [5

Table 2

Plant species sampled for Frankliniella occidentalis (WFT) indicating presence (+) or absence (-) of

WET and presumed WFT larvae. Max. WFT density is the maximum density (# of adults plus larvae

per gram dry weight of plant material) recorded for a plant based on an exact count. Abbreviations:

N=native species; I=introduced species; F=forb; H=herb; S=shrub; T=tree; V=vine; A=annual;

B=biennial; P=perennial.

Max.

Plant Typeof WFT WET No.

ET Grist plant adults larvae mn ak ie

density P

ACERACEAE

Acer macrophyllum Pursh N T + - 0.7 2

APIACEAE

Daucus carota L. I BF a a 0.2

Lomatium columbianum Mathias and N PF i a 05 \

Constance

Lomatium grayi Coult. and Rose N PF + + 21.6 8

Lomatium nudicaule (Pursh) Coult. N PF i 1 02 )

and Rose

Lomatium triternatum (Pursh) Coult. N PF ; ; 0 ;

and Rose

APOCYNACEAE

Apocynum androsaemifolium L. N PF + at 24.8 2)

ASCLEPIADACEAE

Asclepias speciosa Torr. N PF - + 25009 8

ASTERACEAE

Achillea millefolium L. N PF + af: 62.5 63

Agoseris glauca (Pursh) Raf. N PF =p a5 0.2 2

Ambrosia artemisiifolia L. I AF a7 2 12 l

Artemisia tridentata Nutt. N S si =F 30.4 80

Artemisia sp. N S ae a 3 6

Balsamorhiza hookeri Nutt. N PF + Ss 20.4 6

Balsamorhiza sagittata (Pursh) Nutt. N PF + ++ 27.8 a7

Centaurea cyanus L. I AF tr sa 2168 4.

Centaurea diffusa Lam. I A/BF se + 9.9 13

Chaenactis douglasii (Hook.) Hook. N B/PF i 7 191 14

and Arn.

Chrysothamnus es (Hook.) N S ue = 58.7 84

Cirsium arvense (L.) Scopoli I PF ar a 34.4 2

Cirsium undulatum (Nutt.) Spreng. N B/PF + = 1.8 y)

Crepis acuminata Nutt. N PF = + 15.7 14

Crepis occidentalis Nutt. N A/PF + + 0.7 4

Crocidium multicaule Hook. N AF F - 11.4 l

Dieteria canescens (Pursh) Nuttall N B/PF +f =F 7 10

Ericameria nauseosa (Pall. ex Pursh)

G. Nesom and G. Baird N * ue ree ue

Erigeron filifolius (Hook.) Nutt. N PF + + 10.5 8

Erigeron linearis (Hook.) Piper N PF af - 4.3 8

Erigeron pumilus Nutt. N PF - - 0 1

Eriophyllum lanatum (Pursh) J. N PF a 03 5

Forbes

Helianthus cusickii A. Gray N PF “p + 61.1 7

Iva axillaris Pursh N PF ag - 107.2 d

16 J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Max.

Plant Typeof WET WET No. of

Host plant eet WEFT

O lant dult larvae ;

rigin plan adults arv density samples

Lactuca serriola L. I AF - - 0 6

Layia glandulosa (Hook.) Hook. and N AF i re 19 3

Arn.

Nothocalais troximoides (A. Gray) N PF i rs 13 5

Greene

Pyrrocoma carthamoides Hook. N PF ss + 0.6 8

Senecio integerrimus Nutt. N BF + SE 6.2 4

Solidago lepida DC N PF + + 35) 15

Stephanomeria tenuifolia (Raf.) H. N PF i " 08 3

M. Hall

Tragopogon dubius Scop. I A/BF a a 13 8

BERBERIDACEAE

Berberis aquifolium Pursh N S a5 a 0.8 S)

BORAGINACEAE

Amsinckia lycopsoides Lehm ex

Fisch. and C.A. Mey N ae i aa :

Amsinckia tessellata A. Gray N AF a 62.1 10

Cynoglossum grande Dougl. ex N PF ; F 0 ,

Lehm.

Lithospermum ruderale Dougl. ex N PF ; 12 3

Lehm.

Mertensia longiflora Greene N PF =z: a l 2

BRASSICACEAE

Chorispora tenella (Pall.) DC I AF ss - 0.4 1

Descurania sophia (L.) Webb and AF nt es 5 | 5

Prantl

Erysimum capitatum (Dougl. ex N B/PE fs a 22 )

Hook.) Greene

Lepidium perfoliatum L. I A/BF - + 10.7 3

Phoenicaulis cheiranthoides Nutt. N PF ce zs a 1

Sisymbrium altissimum L. I A/BF + + 60.7 9

Thelypodium laciniatum (Hook.) N BF : a 97.5 4

Endl.

CAPRIFOLIACEAE

Lonicera ciliosa (Pursh) Poir. ex DC. N PV - - 0 l

Sambucus cerulea Raf. N S t: + 31.7 4

Symphoricarpos albus (L.) Blake N S + + 6.2 8

CHENOPODIACEAE

Kochia scoparia (L.) Schrad. I AF + a 30.4 8

Chenopodium album L. I AF =F a 9 2)

Grayia spinosa (Hook.) Mog. N S =f + 18.2 10

Salsola tragus L. I AF ale aL (ey) 12

CLUSIACEAE

Hypericum perforatum L. I PF BE i 1.2 l

CORNACEAE

Cornus sericea L. N S + = <0.1 2

FABACEAE

Astragalus sp. N PF + A 14.9 3

Cytisus scoparius (L.) Link I S AG ay 4.9 3

Lupinus lepidus Doug]. ex Lindl N PF + + 23 4

Lupinus wyethii Wats. N PF =e 2 36.9 10

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011 by

Max

lant f WET WET ; No.

Host plant Be sae hee WET once

rigin _— plant adults larvae : samples

density

Medicago sativa L. I A/PF f a 138.7 14

Melilotus officinalis (L.) Lam. I A/PF =p i 178.2 19

Trifolium a (Pursh) N PF ie me 1.9 )

Trifolium pratense L. I B/PF at aa 28.4 3

Trifolium repens L. I PF + + 128.4 22

GROSSULARIACEAE

Ribes aureum Pursh N S + Si 0.9 |

Ribes cereum Dougl. N S a af l Z

HYDRANGEACEAE

Philadelphus lewisii Pursh N S ete ob 89.4 a

HYDROPHYLLACEAE

Phacelia hastata Doug}. ex Lehm. N PF 3 - 23423 13

Phacelia linearis (Pursh)Holz. N AF cf + 10.8 J

IRIDACEAE

Olsynium douglasii A. Deitr. N PF - - 0 l

LAMIACEAE

Agastache occidentalis (Piper) Heller N PF si SE 29.4 18

Salvia dorrii (Kellogg) Abrams N S ate a 17.6 p)

LILIACEAE

Allium acuminatum Hook. N PF +r 2 255 Z

Asparagus officinalis L. I PF +r =f 26.2 l

Calochortus macrocarpus Doug}. N PF ai + 1.9 l

Triteleia grandifora Lindl. N PF + + 4.1 ps

Zigadenus venenosus S. Wats. N PF a - 0.3 +

MALVACEAE

Sphaeralcea grossulariifolia (Hook.

and Arn.) Rydb. “ a - = 2 :

Sphaeralcea munroana (Doug] ex

Lindl.) Spach ex Gray a me z 7 he :

ONAGRACEAE

Epilobium angustifolium L. N PF as - 4 l

PLANTAGINACEAE

Plantago major L. I PF - ~ 0 l

POACEAE

Bromus tectorum L. I AH + =F 1.1 |

Schedonorus arundinaceus (Schreb.) I PH ; : 0 ,

Dumort.

Secale cereale L. I A/BH ate =f 1.8 l

POLEMONIACEAE

Collomia ene Dougl. ex N AF a rm 09 A

Ipomopsis aggregata (Pursh) V. Grant N B/PF af ef <0.1 1

Phlox hoodii Richards N PF af =f coe) 10

Phlox longifolia Nutt. N PF a ete S71 5

Phlox speciosa Pursh N PF + + 2.6 6

POLYGONACEAE

18 J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Max.

Plant Typeof WEFT WET No. of

Host plant - WEFT

Origin lant adults larvae ; sampl

P density ee

Eriogonum compositum Doug. ex N PF i i 61.5 6

Benth.

Eriogonum elatum Dougl. N PF =f F 150.9 86

Eriogonum heracleoides Nutt. N PF + + 48.2 6

Eriogonum microthecum Nutt. N PF a cs 35.8 15

Eriogonum niveum Douglas ex Benth. N PF a a 23.4 at

Eriogonum strictum Benth. N PE + + 76.4 4

Eriogonum thymoides Benth. N PF + + ie) 4

Rumex crispus L. I PE + ete 12.9 if

RANUNCULACEAE

Clematis ligusticifolia Nutt. N PV + +- TA 28

Delphinium nuttallianum Pritz. ex

Walp. N PF 5 se 0.9 3

RHAMNACEAE

Ceanothus as Hook. & N S ne i 4] 6

Ceanothus velutinus Doug}. ex Hook. N S =F + 0.1 2

Frangula purshiana (DC.) Cooper N S/T te as 2D 2

ROSACEAE

Amelanchier alnifolia (Nutt.) Nutt. ex N S/T i a 04 6

M. Roemer

Crataegus douglasii Lindl. N S/T + - <0.1 y)

Holodiscus discolor (Pursh) Maxim. N S + = 40.3 3

Prunus avium (L.) L. I T + + Li2 4

Prunus emarginata (Dougl. ex Hook.) N S/T - Ei 05 7

D. Dietr.

Prunus virginiana L. N S/T tr - 1.4 4

Purshia tridentata (Pursh) DC N S SF + 18.7 aA

Rosa woodsi Lindl. N S =f; ate 88.7 1]

Rubus armeniacus Focke I S/V — = 23.4 4

RUBIACEAE

Galium aparine L. N AF - - 0 1

SALICACEAE

Salix exigua Nutt. N S/T =F as Sia 15

SANTALACEAE

Commandra umbellata (L.) Nutt. N PF i a 0.9 fl

SAXIFRAGACEAE

Heuchera cylindrica Doug]. ex Hook. N PE + - 0.6 Z

Lithophragma parviflorum (Hook.) N PF ; ; 0 7

Nutt.

SCROPHULARIACEAE

Castilleja thompsoni Pennell N PF a str 34.1 9

Collinsia parviflora Lindl. N AF - - 0 l

Linaria dalmatica (L.) Mill. I PF a a 1.2 2

Penstemon humilis Nutt. ex Gray N PF 1 Ss 8.8 6

Verbascum blattaria L. I BF aE - 0.1 l

Verbascum thapsus L. I BF an - <0.1 2

URTICACEAE

Urtica dioica L. N PF + + 9.3

—

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

intensive sampling would have found WFT on

both L. triternatum and E. pumilus.

Frankliniella occidentalis reached very

high densities on some host plants, exceeding

100 individuals per gram dry weight of plant

material in samples from eight species (Table

2). Many of our nearly 1200 samples

contained several thousand thrips. For

example, an exact count of thrips from an 86.2

g sample of flowering Ericameria nauseosa

(Pall. ex Pursh) G. Nesom and G. Baird

(Asteraceae) yielded 10,320 adult WFT, 26

unidentified adult thrips, and 1,079 larvae. A

25.2 g sample of flowering Asclepias speciosa

Torr. (Asclepiadaceae) produced 5,503 adult

WFT, 26 unidentified adults, and 951 larvae.

This was the highest density recorded during

the study, at 255.9 WFT per gram of plant

tissue. WFT was by far the most abundant

species of Thysanoptera on the majority of the

host plants sampled during this study. Samples

from Eriogonum elatum Dougl.

(Polygonaceae) (86 samples over two years)

ylelded 26,255 total adult thrips and 61,162

larvae. Only an estimated 143 adults (<1%)

were not WFT.

These other thrips included a species

tentatively identified as another Frankliniella.

This thrips occurred on most Asteraceae and

in some samples equaled or exceeded WFT in

number. The most extreme example was

Pyrrocoma carthamoides Hook. (Asteraceae).

This plant was sampled for eight consecutive

weeks in 2002 from the pre-bloom stage to the

post-bloom stage. Although WFT was found

in each sample it was greatly exceeded in

abundance by the second putative

Frankliniella species. Other genera of

Thysanoptera were also abundant on occasion.

A species of Haplothrips (probably

Haplothrips verbasci (Osborn, 1897); Horton

and Lewis 2003) was dominant on Verbascum

thapsus L. (Scrophulariaceae). A sample of V.

thapsus late in its 2002 flowering period

yielded 1040 Haplothrips (adults and larvae)

but only four WFT.

Plant phenology and thrips counts. We

present phenology data from two extensively

sampled sites (Durey and Hambleton; Table 1)

west of Tieton (Fig. 1); the two sites are

separated by approximately 1 km. Plant

diversity was high in the habitat adjacent to

the orchards at both sites. Plants in flower

were present at the two sites on all dates

between early-April and mid-October (Fig. 1).

Species that bloomed early included

Balsamorhiza sagittata and other forbs. Late-

flowering species included Chrysothamnus

viscidiflorus (Hook.) Nutt. (Asteraceae) and

Eriogonum microthecum Nutt. (Polygonaceae)

(Fig. 1). One plant species, Eriogonum

elatum, had a very long flowering period, first

showing blooms in late-June and flowering

well into October (Fig. 1).

WET was present, often in large numbers,

throughout the sampling period at these sites

(Fig.1). Generally, WFT occurred at only low

densities on plants in the weeks preceding

bloom. WFT density increased during the

flowering period, and larval thrips greatly

outnumbered adults in some samples from

some plant species. For example, a peak

bloom sample from Phacelia hastata Dougl.

ex Lehm. (Hydrophyllaceae) yielded 297

WFT adults and 2594 thrips larvae. Post-

bloom densities of thrips were usually low,

and the near disappearance of the insect

during the immediate post-bloom period could

be rapid (see also section on thrips and

predator phenology, below). The perennial E.

elatum was notable for its lengthy flowering

period and relatively high densities of thrips.

Throughout the flowering period WFT was

present at densities as high as 150.9 per gram

dry weight of E. elatum plant material.

Densities on E. elatum remained high well

into October when most other plant species

had passed out of bloom (Fig. 1). From late

June to late September larvae usually

outnumbered adults and comprised up to 90%

of a sample. Since WFT were virtually the

only adult thrips in our samples most larvae

were undoubtedly this species. Thus E. elatum

appears to be an excellent reproductive host

for WFT.

Shrubs, which remain relatively green and

succulent throughout the season, often

supported WFT even when not in flower.

Chrysothamnus viscidiflorus, Ericameria

nauseosa, and Artemisia tridentata flower in

late-summer or fall, but pre-bloom samples as

early as mid-May from all three species

yielded WFT adults and thrips larvae at low

densities (<1.0/gram dry weight).

Purshia tridentata presented an interesting

case. Purshia flowers heavily for about four

weeks in late-spring (Fig. 1). WFT density

peaked late in the flowering period or during

early post-bloom and then declined gradually

over the next several weeks. From mid-July to

early-September it was present at very low

densities, and no adults were found in some

samples. Then, in mid-September, adults

began to show up in increasing numbers and

were present through the end of October (Fig.

1), despite the absence of blooms. These late

season individuals were almost exclusively

females. WFT was found in the surface soil

and litter beneath Purshia shrubs in late

autumn, apparently in preparation for

overwintering (unpublished observations).

Predators of Frankliniella occidentalis

and predator phenology. Minute pirate bugs

(O. tristicolor) were the most abundant thrips

predators collected. Adult and/or nymphal

pirate bugs were collected from 64 host plants

(Table 3) all of which also hosted WFT. Orius

generally attained its highest densities on host

plants that also supported high densities of

WFT, such as Achillea, Medicago,

Eriogonum, Clematis, and Trifolium (Tables 2

and 3). Plants on which both insects reached

high densities tended to have long flowering

periods, and 18 of the 20 species on which the

Eriog. microth.

Chrysothamnus

Eriog. elatum

Iva

Crepis

Allium

Eriog. compos.

Agastache

Phacelia

Achillea

Enigeron

Purshia

Castilleja

Amsinckia

Lupinus

Balsamorhiza

April

May

June

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

highest WFT densities were recorded had

flowering periods lasting a minimum of four

weeks. A second factor that may contribute to

high Orius and WFT densities on some plants

may be flowering phenology. Chrysothamnus

viscidiflorus, Ericameria nauseosa, and

Artemisia tridentata flowered during late

summer and fall. This phenological pattern

may have tended to concentrate insects on

these plants because fewer species are in

flower so late in the season (Fig. 1).

Orius phenology appeared to track bloom

and thrips phenology. The phenologies of the

bloom, the WFT, and Orius on three plant

species chosen because of differences in

flowering times are compared in Figure 2:

Achillea millefolium L. (Asteraceae) (early

bloom), Chrysothamnus viscidiflorus (late

bloom), and Eriogonum elatum (season-long

bloom). The samples were obtained at the

Hambleton site in 2002. Densities of Orius

appeared to peak during bloom, and at or just

following peak numbers of thrips (Fig. 2).

Densities of both insect species declined

rapidly following bloom. In Figure 3, we show

age structure of the Orius specimens for each

x No thrips in sample

@ 0-5 thrips perg

10-20 thrips per g

>20 thrips per g

©ee@eeo oXeoKxNxx eo XX GS oo e

July Aug Sept Oct

Figure 1. Flowering periods (shaded bars) of selected WFT host plants based on the Durey and

Hambleton sites near Tieton, WA, and densities of WFT in pre-bloom, bloom, and post-bloom

collections. Most plant species occurred at both sites.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

of these host plants. Adults and nymphs were

present in virtually all samples in which Orius

was collected. The results for E. elatum

suggest that Orius completed two generation

on this one host species (Fig. 3). Females

dominated the last two collections on E.

elatum (Fig. 3).

The other common taxon of predators

found during this study was the Araneae.

Eleven families and at least 20 genera of

spiders were collected from 69 plant species

(Table 3). The spiders occurred in large

numbers and considerable diversity on several

plant species. In general, those plant species

on which WFT was abundant also had high

spider abundance.

Several spider species were found on

certain host plants primarily as first and

second instar spiderlings (Table 3). Because of

their small size, prey for these young spiders

is probably restricted to small arthropods.

Given its great abundance on many of the host

plants, WFT would appear to provide a readily

available supply of prey for these small

predators. Thirty-seven plant species had one

Or more spider genera represented by small

spiderlings, among the more important plants

being Achillea, Chrysothamnus, Medicago,

Agastache, Eriogonum elatum, and Clematis.

Small crab spiderlings in the genus Xysticus

(Thomisidae), especially Xysticus cunctator

Thorell, 1877, occurred on 33 of the plants. A

second thomisid, Misumenops lepidus

(Thorell, 1877), was found as small

spiderlings on 13 plants.

Generally, positive species identification of

spiders requires examination of adults.

Because of our familiarity with the local

fauna, however, we were able to identify

many of the immatures in our samples. The

genus Xysticus was represented primarily by

X. cunctator, Misumenops by M. lepidus, and

Sassacus (Salticidae) by Sassacus papenhoei

Peckham and Peckham, 1895. Local

Phidippus species (Salticidae) are difficult to

distinguish during the first two or three

instars. Based upon our knowledge of the

local fauna, the Phidippus complex in our

samples probably included Phidippus johnsoni

(Peckham and Peckham, 1883), Phidippus

comatus Peckham and Peckham, 1901,

Phidippus clarus Keyserling, 1885, and

Phidippus audax (Hentz, 1845). All seven of

these species occur in local orchards.

Predators other than Orius and _ spiders

were found on 38 species of plants, but were

uncommon compared to those two groups.

Fourteen insect families were represented.

Predaceous Miridae (Deraeocoris brevis

(Uhler, 1904) and Campylomma_ verbasci

(Meyer-Diir, 1843)) were extracted from18

host plants. Several species of lady-beetle

adults and larvae (Coccinellidae) were

extracted from 17 plant species, but the

number found in a given sample was rarely

more than five individuals. The next most

common families were: Geocoridae (found on

13 plant species), Chrysopidae (9),

Hemerobiidae (6), Anthocoridae (Anthocoris

spp.) (6), Phymatidae (6), Nabidae (6), and

Reduviidae (5). The remaining families were

each taken on only one or two plant species:

Raphidiidae, Melyridae, Syrphidae,

Coniopterygidae, and Cleridae.

Ants (Formicidae) occurred in samples

from 64 plant species and were represented

primarily by workers, although an occasional

alate form was taken. The number of

specimens in a sample was rarely more than

two or three, and many collections from host

plants sampled multiple times contained no

specimens. For example, 56 samples were

collected from Artemisia tridentata at seven

sites in 2002, but ants occurred in only two of

them. Some ant species are predaceous, but

we made no attempt at identification below

the family level.

DISCUSSION

The western flower thrips, causative agent

of pansy spot on apple, was found on 92% of

the plant species sampled in near-orchard

habitats during this study. These results

(indicating a broad utilization of available,

non-cultivated host plants) are in agreement

with findings from other parts of the thrips’

native range (Bryan and Smith 1956; Yudin ez

al. 1986) and also regions into which WFT

has been introduced (Chellemi eft al. 1994;

Atakan and Uygur 2005). Madsen and Jack

(1966), Pearsall (2000), and Cockfield ef al.

(2007) reported WFT from a number of non-

cultivated host plants in near-orchard habitats

22 J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Table 3

Occurrence and maximum density (# per gram dry weight of plant material) of Orius spp. and spiders

on sampled host plants. Maximum spider density includes all spiders found in the sample. Plants on

which neither Orius nor spiders were found are not included. Orius stages: m=male; f=female; 1, 2, 3,

4, 5 indicate the five nymphal instars. Abbreviations for spider taxa: A=Anyphaena; Ar=Araneidae;

C=Coriarachne; D=Dictynidae; E=Ebo; H=Hololena; Ha=Habronattus; L=Linyphiidae;

M=Misumenops; Mi=Misumena; O=Oxyopes; P=Phidippus; Pe=Pelegrina; Ph=Philodromus;

Ps=Phanias; S=Sassacus; T=Theridion; Te=Tetragnatha; Ti=Tibellus; X=Xysticus. ‘Indicates a spider

taxon represented primarily by 1‘ and 2"4 instar spiderlings. See text for further explanation.

Orius stages Max.Orius Max. spider

Host plant DEeSent density Spider taxa present density

Acer -- -- L <0.1

Daucus 5 0.1 M! 0.2

Lomatium grayi = -- D <0.1

L. columbianum -- -- L <0.1

Apocynum m,2,3,4 <0.1 X1.M,D,L <0.1

Asclepias f,m,3,4,5 0.6 X!.Ph,S,P,D 0.5

Achillea f,m,1,2,3,4,5 29 X!,M!,S,P!,Pe,T,Ph,Mi,C,A,L,D 0.7

Ambrosia f <0.1 -- --

Artemisia sp. f,m,2,4,5 0.3 X!,8,Pe <0.1

A. tridentata f,m,1,2,3,4,5 <0.1 X,M.S,Pe,T,Ph,L,D,H,Ha 0.2

Balsamorhiza hookeri 3,4 <0.1 M <0.1

B. sagittata {,m,1,2,5,4,5 0.6 M,S,T,0,L 0.1

Centaurea cyanus -- -- Ar <0.1

C. diffusa ,10,2,3,5 0.1 -- --

Chaenactis P2345 0.7 XE MLL 0.2

Chrysothamnus £m.1,2.3:4,5 23 X!\M!,S!,P!,Ph,Pe,D 0.4

Cirsium arvense £m.1,2.3.4;5 0.9 X!\M!.P! Ph,A,D,L 0.4

C. undulatum m,3.4 0.2 Xx! 0.1

Crepis acuminata m,5 <0.1 XL <0.1

C. occidentalis m <0.1 -- --

Ericameria f;m,1,2,3,4,5 1.3 X,M!-S!,P,Pe,A,Ph,L,D <0.1

Erigeron filifolius 2,3,4 0.4 -- --

E. linearis 23.5 0.4 Xx! 0.1

Helianthus f,m,1,2,3,4,5 0.5 -- --

Iva f,m,1,2,3,4,5 0.8 XL <0.1

Lactuca -- -- T <0.1

Layia -- -- M <0.1

Dieteria 2 <0.1 D,L 0.1

Nothocalais -- -- S 0.3

Pyrrocoma £125 <0.1 X,E <0.1

Solidago f,m,1,2,3,4,5 1.3 X!\M} .P.S,Pe,L <0.1

Tragopogon -- -- Xx! <0.1

Berberis -- -- T,O,L <0.1

Amsinckia lycopsoides 1,4 0.3 L <0.1

A. tessellata f,3,4,5 <0.1 XL <0.1

Descurania 2 <0.1 -- --

Lepidium -- -- L <0.1

Thelypodium 2,3,4 0.2 -- --

Lonicera -- -- T <0.1

Sambucus m <0.1 -- --

Symphoricarpos -- -- L <0.1

Kochia 1,2 <0.1 M!,Pe <0.1

Chenopodium 1,2,3,4,5 0.4 M,D <0.1

Grayia f,4 <0.1 -- --

Salsola f,1,2,3,4,5 0.3 T,Ph,Ps,L,D 0.2

Hypericum 3,4,5 0.2 -- =

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Host plant Orius stages Max.Orius

present density

Lupinus lepidus 3 <0.1

Medicago f,m,1,2,3,4,5 4.8

Melilotus f,m,1,2,3,4,5 1.3

Trifolium

macrocephalum > _

T. pratense f,1,2,3,4,5 1.7

T. repens f,m,1,2,3,4,5 5.2

Ribes aureum -- --

R. cereum ~ --

Philadelphus f,m 0.7

Phacelia hastata f,m,2,3,4,5 0.8

P. linearis m,1 0.2

Agastache f,m,1,2,3,4,5 4.0

Salvia f <0.1

Dado a 24,5 0.1

grossulariifolia

S. munroana f,m,1,2,3,4,5 0.5

Phlox hoodii ae <0.1

P. longifolia f <0.1

Prono £m,2,3,4,5 0.5

compositum

E. elatum f;m,1,2,3,4,5 Tad

E. heracleoides £m;1,2,3,4;5 0.8

E. microthecum f;m,1,2,3,4,5 0.3

E. niveum f;m,1,2,4 0.1

E. strictum f,m,1,2,3,4,5 0.7

Rumex f,m,1,2,3,4,5 22

Clematis f£,m,1,2,3;4,5 4.0

Ceanothus

integerrimus i a

C. velutinus -- --

Frangula -- --

Crataegus -- --

Holodiscus 5 <0.1

Purshia f,m,1,2,3,4,5 <0.1

Rosa m,1 <0.1

Rubus f,m,1,2,3,4,5 0.7

Salix m,2,3 <0.1

Castilleja f,m,2,3,4,5 0.3

Verbascum thapsus m,3,4,5 0.3

Urtica f,1,2,3,4,5 2.6

Spider taxa present Mess SP a

density

S <0.1

X/ Meo) Ph.Pe <0.1

X!\S,Ph <0.1

L <0.1

Pp? <0.1

XM.P Pb, TU 02

M,T <0.1

S =); ]

X}\S,Pe <0.1

OF 0.3

x! 0.2

X},MLL 15

X!.M <0.

X!\Ph <0.1

S,Ph,T,L 02

XMS! ,P! Pe!,O',.D,L 0.4

X! <0.1

X!\M,S!,P,Pe 0.1

M,S <0.1

XE 0.2

X! =I

X!,M!,S!,P!,A) DD! Pe,Ps,L 2.0

M,Mi,D <0.1

D <0.1

H <0.1

M,Pe <0.1

XL IVGS.P? Pe Ph DAL <0.1

X*,Pe.O, Ph, DoE <0.1

M 0.1

D <0.1

x! <0.1

X! <0.1

of the Pacific Northwest and discussed

implications for damage to apples and

nectarines. Our study concentrated on plants

growing outside of orchards, but several

species that are common components of

orchard understories, including red clover,

white clover, and alfalfa, also supported large

numbers of WFT. Venables (1925) remarked

on the occurrence of WFT on alfalfa growing

in orchards and its possible bearing on pansy

spot of apple.

Frankliniella occidentalis, like other

winged thrips, is a highly mobile insect, and

active or passive flights are the primary means

of dispersal among thrips as a group (Lewis

1973). Gravid females of many species make

local flights among host plants apparently as

they search for oviposition sites (Lewis 1997).

Flower-loving species like WFT may detect

changes in the quality of these short-lived

resources prompting movement within or

between plants as their food value declines

(Terry 1997). Madsen and Jack (1966),

Cockfield et al. (2007), and Pearsall (2000)

discussed movement of WFT between

successively blooming host species and

flowering orchards. At some of our sites,

dozens of host plant species were available

over the course of the season in the near-

orchard habitat, and additional species were

present in the orchard ground cover.

Cultural control of WFT by elimination of

alternate hosts does not seem to be a viable

option (Cockfield et al. 2007), and alternate

hosts that flower concurrently with the crop

may even mitigate damage by diluting the

thrips population (Beers ef a/. 1993). Pearsall

(2000) did not believe that a trap crop would

effectively reduce damage in nectarines.

Natural enemies are rare in nectarine orchards

in British Columbia during the spring

(Pearsall 2000), and we noted few natural

enemies in apple flowers (unpublished

<= Bloomn=>

Thrips counts (no. per g plant material)

Eriogonum elatum

RAL

May June July

Chrysothamnus viscidiflorus

80 <= Bloom —_——__>

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

observations). In apple orchards, careful

monitoring of WFT densities and application

of a suitable insecticide timed to eliminate

females that are laying eggs on developing

apples (while avoiding harm to pollinators)

may be the best management approach

(Madsen and Jack 1966; Cockfield eft al.

2007). In some cases it may be possible to

limit sprays to border rows (Miliczky et al.

2007).

Many of the same plants that were hosts

for WFT also hosted known and potential

thrips predators, sometimes in considerable

numbers. Orius spp. are important thrips

predators throughout the world (Lewis 1973).

The minute pirate bug, O. tristicolor, was the

most abundant predator on many plants

Achillea millefolium

—@— western flower thrips

++ Orius tristicolor

<= — Bloom—>

(jeeyew juejd 6 sad ‘ou) sjunod Jojepaig

Oct

Aug

Figure 2. Correspondence between flowering period, WFT abundance, and abundance of the important

thrips predator Orius tristicolor on three important WFT host plants in flower at different times during

the season. Figure is based on 2002 data from the Hambleton site.

Sept

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

ENCE NENG ENCE EEE

No Orius in samples

SANSA NNANAN

Chrysothamnus

viscidiflorus

Proportion of sample

SENSES

ples

SOK

us insam

NAAANA

Not sampled

0.4 4

No On

SAX

Proportion of sample

No Orius in samples

]

Yj);

May June July

— No Orius in samples

NSN]

SSeS

Achillea millefolium

mum Females

mea Males

ZZZ 1-3N

esa 4-5N

Not sampled

Ne) PO ph adtg

PENNE NENG NGC NCO EG?

Aug. Sept. Oct.

Figure 3. Age structure of Orius tristicolor in collections from the same three host plants as in Fig. 2 at

the Hambleton site in 2002. Number at the top of each column indicates the total number of Orius in

the sample.

sampled in this study. Barber (1936) noted

that O. insidiosus could be “swept from

almost any plant association”, and Kelton

(1963) commented on the abundance of Orius

spp. on the flowers of various plants.

Numerous plant species supported populations

of O. insidiosus near apple orchards in

Virginia (including other crops and various

weeds) (McCaffrey and Horsburgh 1986).

Kakimoto eft al. (2006) found a significant

correlation between the density of Orius

sauteri (Poppius, 1909) and thrips on spring

weeds in Japan. Tommasini (2004) showed

that non-cultivated host plants of WFT in Italy

also supported species complexes of minute

pirate bugs. Orius tristicolor occurred on 32

flowering plant species in north-central

California, in all cases feeding on thrips, most

frequently WFT (Salas-Aguilar and Ehler

1977). The early-season presence of thrips in

Indiana soybean fields led to colonization of

the crop by O. insidiosus and, in some years,

the predator was then able to hold the later

arriving soybean aphid Aphis glycines

Matsumura, 1917 at low levels (Yoo and

O’Neil 2009).

While Orvius seem to prefer thrips as prey,

they are generalist predators and a variety of

other small prey items including mites, aphids,

scale insects, leafhoppers, and Lepidoptera

eggs and larvae are fed upon (McCaffrey and

Horsburgh 1986). Pirate bugs may feed and

partially develop on pollen (Kiman and

Yeargan 1985; McCaffrey and Horsburgh

1986). Thus, an association with flowers gives

Orius spp. access to both animal and plant

food.

Sabelis and Van Rin (1997) noted that

surprisingly little was known about spider

predation on thrips, although they predicted

that thrips were most likely to be important

components of the diets of smaller species.

Thrips comprised 9% of the prey of the small,

cribellate spider Dictyna arundinacea

(Linnaeus, 1758) (Heidger and Nentwig

1985), and webs of Dictyna coloradensis

Chamberlin, 1919 often captured thrips, most

of which were probably WFT (Miliczky and

Calkins 2001). A recent greenhouse study

using caged pepper plants infested with WFT

indicated that in the presence of second instar

Xysticus kochi Thorell, 1872, thrips damage to

the peppers was reduced, and the peppers

produced were of higher quality (Zrubecz et

al. 2008).

The present study indicates that at certain

times when thrips are abundant, they likely

comprise a substantial portion of the diet of

the early instars of various spiders. Early

instars of these spiders, because of small size,

are restricted to small prey. Due to the nature

of the sampling procedure employed in this

study actual predation of thrips by spiders was

not observed. However, during a previous

study (Miliczky and Horton 2007) in which

beneficial arthropods were collected by

beating several of the same plant species at the

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

same locations, small spiderlings of the

species referred to above were observed with

thrips prey in their mouthparts (unpublished

observations).

In summary, the great majority of

flowering plant species that occur in

uncultivated land adjacent to eastern

Washington apple orchards, as well as some

ground cover species within the orchards, are

hosts to WFT. WFT colonizes host species

primarily while they are in flower, reproduces

on many of them, and often reaches very high

population levels. Small, immature spiders

(especially first and second instars) of several

species were numerous on some of the same

plant species. WFT, because of its small size,

great abundance, and ubiquitous occurrence is

probably an important component in the diet

of these small, young spiders, which because

of their size, are restricted to suitably small

prey. These spiders, as they mature and grow,

will switch to larger prey. Orius tristicolor, an

important thrips predator, occurs on many of

the same plant species as WFT, is also able to

reproduce on many of them, and builds up

high numbers on some species. Both WFT and

O. tristicolor appear to track available host

plants, moving from one to the other as

successive species come into flower.

ACKNOWLEDGEMENTS

This research was funded under an

Initiative for Future Agriculture and Food

Systems (IFAFS) grant and by a grant from

the Washington Tree Fruit Research

Commission. We thank Tom Unruh (USDA-

ARS), Elizabeth Beers (Washington State

University), and two anonymous reviewers for

their constructive comments on the

manuscript. Merilee Bayer provided

invaluable field and laboratory assistance

throughout this study. We also thank the pear

and apple growers who kindly allowed us to

sample in habitats near their orchards, and in

some cases in their orchards: Scott Leach, Rob

Lynch, Dave Carlson, Tom Hattrup, Rick

Valicoff, Orlen Knutson, Ted Alway, Harold

Hambleton, and Craig Campbell.

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J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Drymus brunneus (Sahlberg) (Hemiptera: Rhyparochromidae):

a seed bug introduced into North America

G.G.E. SCUDDER!, L.M. HUMBLE’, and T. LOH?

ABSTRACT

The occurrence of the adventive Drymus brunneus (Sahlberg) in North America is

documented, and characteristics to distinguish this Old World species from D. unus (Say) are

described and illustrated. A revised key to the Western Hemisphere species of Drymus is

included.

INTRODUCTION

Elsewhere (Scudder and Foottit 2006)

reported this Old World seed bug from

Richmond, British Columbia in 1966 as the

first record from North America. We have now

been able to assemble collection records and

appropriate illustrations to document the

identity of this species and distinguish it from

the similar D. wnus (Say), a species native to

eastern North America. A revised key to the

Western Hemisphere species of the genus

Drymus Fieber is included to assist in

identification.

Measurements (in millimeters) given in the

description below are mean and range (in

parentheses) from nine specimens of each sex

examined from the Old World. Unless

otherwise stated, all material is in the Scudder

personal collection.

DESCRIPTION

Drymus brunneus (Sahlberg)

Rhyparochromus brunneus Sahlberg 1848,

Monogr. Geoc. Fenn.:57

Pachymerus pallidus Uerrich-Schaeffer

1853, Wanz. Ins. 9:211 (Synonym)

Drymus notatus Fieber 1861, Europ.

Hem. :179 (Synonym)

Drymus brunneus, Stal 1862, Ofv. Vet.

Akad. Forh. 19:217 (Current combination)

Drymus brunneus, Slater 1964, Cat. Lyg.

World 2:884 (Bibliography)

Drymus (Sylvadrymus) brunneus, Péricart

1998, Faune de France 84B:255 (Description)

Macropterous or submacropterous, robust,

subglabrous, and somber coloured. Head and

anterior lobe of pronotal disc dark ferruginous

brown to black; rest of dorsum and venter

dark ferruginous; corium with basal third

tending to be pale ferruginous to ochraceous,

with a more or less distinct pale spot in middle

at junction with uniform darker apical two-

thirds of corium; antenna ferruginous to dark

ferruginous with apical half of third segment

dark brown, and apical half of fourth segment

pale ferruginous; legs ferruginous, with

femora darker.

Head and anterior lobe of pronotal disc

closely punctate; posterior lobe of pronotal

disc and scutellum with larger more dispersed

punctures. Head width ¢ 0.87 (0.80-0.92) ©

0.92 (0.83-0.95); first antennal segment

exceeding apex of head by half its length;

second antennal segment with short semi-

decumbent pubescence, but with longer

outstanding setae confined to apical one-fifth;

third and fourth antennal segment as thick as

or thicker than apex of second segment, with

third segment somewhat thicker in apical half

and slightly spindle-shaped; fourth antennal

segment in middle as thick as widest part of

third segment; third and fourth antennal

segments with long erect setae, in addition to

shorter, more dense, decumbent pubescence

along most of length; second antennal

' Beaty Biodiversity Centre and Department of Zoology, University of British Columbia, 6270 University

Boulevard, Vancouver, BC, V6T 1Z4.

2 Natural Resources Canada, Canadian Forest Service, 506 West Burnside Road, Victoria, BC V8Z 1MS.

3 Department of Biological Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6.

segment shorter than head length; on average

second antennal segment 0.94 times head

width, and about 1.3 times length of third

antennal segment; fourth antennal segment on

average about 1.2 times length of third

antennal segment; antennal measurements @

0.47 (0.43-0.48): 0.74 (0.60-0.78): 0.57

(0.53-0.58): 0.68 (0.63-0.72) 2 0.48

0.43-0.53): 0.77 (0.70-0.80): 0.58 (0.50-0.60):

0.68 (0.67-0.70); rostrum attaining middle

coxae.

Pronotum with disc rather convex; with

shallow transverse impression on disc just

behind middle, this impression level with

concave impression on narrowly carinate

lateral margins; on average pronotal width

about 1.4 times pronotal length; pronotal

width @ 1.40 (1.28-1.47) 2 1.49 (1.27-1.60),

pronotal length @ 1.03 (0.92-1.10) 2 1.03

(0.87-1.10). Hemelytron with costal margin

distinctly convex; corium widest just beyond

middle, level with apex of clavus; membrane

reaching middle of last abdominal tergum or

just surpassing apex of abdomen. Fore femora

with a single, minute, ventral spine in apical

half; tibiae lacking long, erect setae.

Total length ¢ 4.19 (3.80-4.40) 2 4.54

(4.40-4.80).

Material examined. (a) Old World:

ENGLAND: 36 29, Berks, Cothill, 10.viii.

1957 (G.G.E. Scudder); 14, Berks, Wytham

Wood, 30.v.1957 (G.G.E. Scudder); 19,

Oxon, Bald Hill, ix.1962; 19, Surrey, Oxshot,

28.vii.1957 (G.G.E. Scudder). RUSSIA: 2)

22, Moscow Distr., Birch Grove, 4.viii.1968

(G.G.E. Scudder). SCOTLAND: 26 29,

Dalkeith, Midlothian, 6.1x.1957 (R.A.

Crowson); 1, Fullerton Est., Troon Ayrshire,

13.ix.1957 (R.A. Crowson); 19,

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Invernesshire, Kinveachey, mixed birch and

pine litter, 15-19.vi1.1957 (R.A. Crowson). (b)

New World: CANADA: 24 19, B.C. Delta,

Alaksen Res., CWS property, pitfall trap,

1 .vii-28.vi1i.2009 (A. Caldicott and B. Bains)

[Royal British Columbia Museum, University

of British Columbia]. 1¢ 39, B.C., Richmond

Nature Park, 23.vi-13.vi1.1996 (L. Humble, J.

Seed) [Pacific Forestry Centre, Victoria;

Scudder Coll.]. 14 29, BC, Coquitlam,

Westwood Plateau, North Hoy Creek Park,

49°19'7.61"N, 122°47'38.18W, 29.viii.2010

(T. Loh) [UBC; T. Loh Coll.]; 19, id., 25.ix.

2010, ex: leaf litter, (T. Loh) [T. Loh Coll.];

34 19, BC, Vancouver, Pacific Spirit Park,

49°16'14.51"N, 123°14'12.26"W, 12.viii.2010

(T. Loh) [CNC; UBC; T. Loh Coll.]; 12, BC,

Coquitlam, Westwood Plateau, Near North

Hoy Creek, 49°18'1.03"N, 122°47'21.03"W,

8.v.2010 (T. Loh) [T. Loh Coll.]; 13 , BC,

Coquitlam, Upper Coquitlam River Trail,

49°18'5.26"N 122°46'1.31"W, 24.vu1.2010 (T.

Loh) [T. Loh Coll.]; 12, BC, Port Coquitlam,

Coquitlam River Park, 49°17'1.88"N,

122°46'22.94"W, 5.viii.2010 (T. Loh) [T. Loh

Coll.]; 1¢ 192, BC, Coquitlam, Upper

Coquitlam River Park, 49°19'36.41"N,

122°46'22.48"W, 13.x.2010 (T. Loh) [UBC; T.

Loh Coll.]; 1¢ 19, BC, Coquitlam, Westwood

Plateau, 49°17'51.66"N, 122°47'2.20"W,

18.1x.2010 (T. Loh) [T. Loh Coll.]; 19, id.,

14.viii.2010, (T. Loh) [T. Loh Coll.]; 14, BC,

Coquitlam, Coquitlam River Park,

49°17'6.04"N, 122°46'31.77"W, 20.x.2010 (T.

Loh) [UBC]; 19, id., 29.vii.2010 (T. Loh) [T.

Loh Coll.]. 24, Surrey, Crescent Park,

49°2.904’"N 122°51.647’W, Pitfall trap CPI,

5.vill-5.x.2010 (J. Heron, L. Parkinson)

[Royal British Columbia Museum].

DISCUSSION

The material from British Columbia

compares well with the description in Péricart

(1998). It also closely resembles the colour

illustration in Southwood and Leston (1959).

However, most of the New World specimens

are fully macropterous, and measurements are

at the upper limits of the range represented in

the Old World material examined. Indeed, the

pronotum of the specimens measured from

Richmond, BC, are both slightly wider and

slightly longer than the Old World specimens

studied.

Three of the Richmond, BC, specimens

were captured in a multiple funnel trap

(Lindgren 1983) baited with a high-release

rate ethanol lure (EBT 1996-0146-06) and one

was obtained in an unbaited 4-panel window

pane trap (EBT 1996-0149-03), during studies

of introduced and native Scolytidae in

southwestern British Columbia (Humble

2001). Trapping was conducted in the west

block of the Richmond Nature Park

(49°10'19.5"N_ 123°05'50"W) that preserves

the last remnants of the Greater Lulu Island

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Bog. A shore pine/Sphagnum moss

community predominates with the dominant

tree species being European white birch

(Betula pendula Roth), as well as hybrids with

the relatively uncommon native white birch

(B. papyrifera Marsh.), together with shore

pine (Pinus contorta var. contorta Dougl.).

Much of the study area has been invaded by a

dense growth of highbush blueberry

(Vaccinium corymbosum L.).

The Surrey, Crescent Park locality was in

the northwest side of the park. This is a

forested area of mostly second growth forest,

with some manicured fields.

Most of the specimens in the T. Loh

collection were obtained by sifting forest leaf

litter, especially around logs or near tree

stumps. Some were sifted or washed from

moss and litter in wet areas near forest

headwater streams (Hoy Creek specimens).

Specimens from Pacific Spirit Park in

Vancouver, BC, were collected mainly from

forest communities dominated by red alder

(Alnus rubra Bong.). Coquitlam specimens

came primarily from forests with mixed

hardwood (Alnus, Populus balsamifera

trichocarpa (T.&G.) Brayshaw, Acer) and

conifers (Zsuga heterophylla (Raf.) Sarg.,

Thuja plicata Donn, Pseudotsuga menziesii

(Mirb.) Franco. A few were collected from a

forest clearing in a backyard on Westwood

Plateau, a suburban residential neighborhood

in Coquitlam, BC. The location coordinates

for most of these records (especially in the

parks) are approximate and do not reflect the

actual location where the specimens were

found.

Southwood and Leston (1959) noted that

D. brunneus in the British Isles frequents

damp places, and is usually found on the

ground amidst litter and mosses, sometimes in

Sphagnum. The Richmond area of British

Columbia is on the coast, close to industrial

sites, where other adventive insects have been

detected.

According to Péricart (1998), D. brunneus

is largely a Euro-Siberian species, widely

distributed in the eastern Palaearctic, with a

range extending into Asia. Slater (1964) and

Péricart (1998) give details of the known

distribution in the Old World. The species

almost certainly was introduced into North

America from the Palaearctic and may

represent a recent accidental introduction.

Drymus brunneus runs to the genus

Drymus Fieber in the key to the genera of

North American Drymini in Ashlock (1979). It

is very similar to D. unus (Say), a widely

distributed native species in eastern North

America (Ashlock and Slater 1988). However,

these two species differ in the coloration of

the hemelytra and in the setation on the

second antennal segment. While both species

are often submacropterous, and have the costal

margin of the corium distinctly convex and the

widest area of the corium level with the apex

clavus. The apical half of the corium is

uniform chocolate brown and without a pale

central spot in D. wnus (Figure 1), whereas in

D. brunneus there is usually a distinct pale

spot in the centre of the basal third of the

corium, adjacent to the border of the darker

apical area (Figures. 2 and 3).

Furthermore, in D. brunneus the second

antennal segment has long erect setae

confined to the apical one-fifth (Figures 4 and

5), whereas such long erect setae occur along

the whole length of the second antennal

segment in D. unus (Figure 6).

The key to the Western Hemisphere

species of Drymus given by Slater and

Brailovsky (1997) can be modified to include

D. brunneus as follows:

Revised key to Western Hemisphere

species of Drymus

1. Distal half of fourth antennal segment

white, strongly contrasting with dark

coloration of basal half of antennae; explanate

lateral margins of pronotum broad, subequal

to width of second antennal segment; second

antennal segment subequal to head

length............ mexicanus Slater & Brialovskey

Fourth antennal segment unicolorous dark

brown to black, or if distal half pale, not white

and strongly contrasting with dark coloration

of basal half of antennae; explanate lateral

margins of pronotum relatively narrow, much

narrower than width of second antennal

segment; second antennal segment

considerably longer than head length............. p)

2. Large, 6.5-7mm; very dark brown to

almost black; anterior and posterior lobes of

pronotal disc nearly evenly punctate;

expanded lateral margins of pronotum

concolorous with dorsal surface of

PFODOMIN thse anes crassus Van Duzee

Smaller, under 5.5 mm; dull brown to

ferruginous brown; anterior lobe of pronotal

32 J. ENTOMOL. SOc. BRIT. COLUMBIA 108, DECEMBER 2011

Figure 1-6. Figs. 1-3. Dorsal view: 1. Drymus brunneus (Sahlberg) 9, British Columbia, Canada,

Richmond Nature Park, EBT96-0146-06, 23.vii-13.viii.1996 (L. Humble, J. Seed) [Scudder Coll.]; 2.

Drymus brunneus 3, Dalkeith Midlothian, UK, 6.ix.1957 (R.A. Crowson) [Scudder Coll.]; 3. Drymus

unus (Say) 2, ONT, Canada, Hilton Beach, Sugar Maple Forest, Pan trap, 16.ix-14.x.1989 (J.E. Swann)

[Scudder Coll.]; Figs. 4-6. Detailed structure of second antennal segment: 4. Drymus brunneus, BC

specimen; 5. Drymus brunneus, UK specimen; 6. Drymus unus, Ontario specimen. Photos by Don

Griffiths.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

disc more finely punctate than posterior lobe;

expanded lateral margins of pronotum usually

slightly paler than surface of anterior pronotal

3. Second antennal segment with long

erect setae confined to the apical one fifth and

margin of darker apical two-

(INIT S rors ncteuace tees vate seenetases brunneus (Sahlberg)

Second antennal segment with long erect setae

distributed along whole length of segment;

basal third of corium without a distinct pale

spot at margin of darker apical two-

not distributed along whole length; basal third ANIC S ease cosissgetvanetnaaeecuee. unus (Say)

of corium usually with a distinct pale spot at

ACKNOWLEDGEMENTS

The photographs reproduced as figure 1-6

were taken by Don Griffiths. Launi Lucas

kindly prepared the manuscript and assembled

Figures 1-6.

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J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Asciodema obsoleta (Hemiptera: Miridae): New Records for

British Columbia and First U.S. Record of an Adventive Plant

Bug of Scotch Broom (Cytisus scoparius; Fabaceae)

A.G. WHEELER, JR.! and E. RICHARD HOEBEKE’

ABSTRACT

The European plant bug Asciodema obsoleta (Fieber) develops mainly on Scotch broom,

Cytisus scoparius (L.) Link; it is one of several broom insects that apparently have been

introduced to North America with shipments of nursery stock. This mirid first was reported in

North America from British Columbia (Vancouver, Vancouver Island, Bowen Island) in 1966,

but no additional records have been published. Based on specimens in BC museums and our

recent field work, we extend the previously recorded BC distribution of A. obsoleta and

provide the first U.S. record: Washington State (Point Roberts, Whatcom County).

Key Words: Canada, Palaearctic immigrant, distribution, new U.S. record, Laburnum

anagyroides, host plants

INTRODUCTION

Scotch broom (hereafter broom), Cytisus

scoparius (L.) Link; Fabaceae), is a genistoid

legume (tribe Genisteae, subfamily Faboideae)

native to central and southern Europe.

Introduced to coastal British Columbia as an

ornamental in the 1850s, the plant became

naturalized, mostly along or near roadsides on

the Lower Mainland, Vancouver Island, and

some Gulf Islands. Although broom no longer

is planted along BC highways for ornament

and slope stabilization, it has become

sufficiently invasive in the Pacific Northwest

to hinder reforestation and threaten native

biodiversity, particularly in Garry oak and

grassland ecosystems (Zielke et al. 1992,

Peterson and Prasad 1998, Coombs ef al.

2004, Haubensak and Parker 2004). Biological

control efforts began in the 1950s, and several

European insects of broom began to be

released in the 1960s in California, Oregon,

and Washington (Andres and Coombs 1995S,

Coombs et al. 2004).

Insects of broom are especially well known

in England. From the mid-1950s to the

mid-1960s, broom insects were studied

intensively at Silwood Park (near Ascot,

Berkshire, SW of London) by J.P. Dempster,

O.W. Richards, N. Waloff and others at

Imperial College, London. Among the 35

insects consistently found on broom were 13

species of Hemiptera. Particular attention was

given to the bionomics of the mirids

Asciodema obsoleta (Fieber), Heterocordylus

tibialis (Hahn), Orthotylus adenocarpi

(Perris), O. concolor (Kirschbaum), and O.

virescens (Douglas and Scott) (Waloff and

Southwood 1960, Dempster 1964, Waloff

1968). The Orthotylus species and H. tibialis

(subfamily Orthotylinae) essentially are

restricted to broom, whereas A. obsoleta

(subfamily Phylinae) also develops on gorse

(Ulex europaeus L.), another genistoid

legume. All five mirids are univoltine and

overwinter as eggs, with their oviposition sites

not overlapping substantially. Eggs hatch

sequentially from March (sometimes April) to

mid-June; adults first appear from about mid-

May to mid-July, and, although all species can

be found concurrently on broom, their periods

of peak abundance differ; and all are

omnivores that feed on the host and

arthropods such as aphids and psyllids (Waloff

and Southwood 1960, Dempster 1964, Waloff

1968).

Three of the British broom Miridae—4.

obsoleta, O. concolor, and O. virescens—were

' School of Agricultural, Forestry, and Environmental Sciences, Clemson University, Clemson SC 29634-0310.

* Department of Entomology, Cornell University, Ithaca NY 14853-2601; current address: Georgia Museum of

Natural History, University of Georgia, Athens, GA 30602.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

accidentally introduced into the Pacific

Northwest, probably with imported nursery

stock (Waloff 1966, Wheeler and Henry

1992). Both species of Orthotylus are recorded

from British Columbia and Pacific U.S. states

(Wheeler and Henry 1992), but published BC

records of A. obsoleta have been limited to

Waloff’s (1966) original North American

study. The earliest collection was from

Vancouver (University of British Columbia

campus), 6.vi1.1959, by G.G.E. Scudder

(Barnes et al. 2000). Syrett et al. (1999)

erroneously attributed the first North

American record of A. obsoleta to Downes

(1957). Waloff (1966), during field work in

June and July 1963, recorded A. obsoleta from

Vancouver (UBC), Vancouver Island (near

Victoria), and Bowen Island (Howe Sound

NW of Vancouver); surveys for the mirid in

the Fraser Valley (and in California) were

negative. Syrett et al. (1999) updated the

status of European insects established on

broom in the Pacific Northwest, noting that no

new information was available for A. obsoleta.

Here we extend the known distribution of

A. obsoleta in BC, report Washington State as

the first U.S. record, and give golden chain

tree (Laburnum anagyroides Medik.;

Fabaceae) as a new host record. We use the

name A. obsoleta rather than A. obsoletum

because the genus Asciodema, considered

neuter by Steyskal (1973), is considered

feminine in the most recent world (Schuh

1995) and Palaearctic (Kerzhner and Josifov

1999) catalogs of the Miridae.

MATERIALS AND METHODS

We collected A. obsoleta in late June of

2010 and 2011 during efforts to update the

distributions of European Hemiptera of broom

in the Pacific Northwest (Wheeler and Lattin

2008, Hoebeke and Wheeler 2010, Wheeler

and Hoebeke 2012). The mirid was collected

into small plastic vials after broom was swept

or its branches were beaten over a shallow net.

In June of both years A. obsoleta dominated

the plant bug fauna of broom in BC. The only

other mirid present as late instars and adults

was O. virescens, whose eggs hatch later than

those of A. obsoleta (Waloff and Southwood

1960). Nymphs of A. obsoleta could be

separated in the field from those of O.

virescens by their darker color, the indistinct

opening of the dorsal abdominal scent gland,

and overall different Gestalt of the late instars.

Under magnification, the parempodia (=

arolia) of A. obsoleta appear hairlike

(setiform) rather than fleshy and apically

convergent, as in O. virescens. Fourth or fifth

instars (n = 5) identified in the field as A.

obsoleta and reared to adulthood all proved to

be that species; similarly, the identity of two

fifth instars of O. virescens was confirmed

through rearing. All collections presented

below (Specimens examined) were made by

the authors and, unless noted otherwise,

Cytisus scoparius was the host plant. Nymphs

are recorded only by the instars observed, e.g.,

IV—V. Voucher material of A. obsoleta is

deposited in the Cornell University Insect

Collection (Ithaca, NY) and the National

Museum of Natural History, Smithsonian

Institution (Washington, DC).

RESULTS AND DISCUSSION

Museum records. Several unpublished

records of the mirid are available, based on

specimens in the Canadian National

Collection of Insects, Agriculture and Agri-

Food Canada, Ottawa, ON (CNC); Royal

British Columbia Museum, Victoria, BC

(RBCM); and Spencer Entomological

Collection, Beaty Biodiversity Centre,

University of British Columbia, Vancouver,

BC (UBC): Lower Mainland: Burnaby Lake,

Burnaby, 9.vi1.1998, D.J.M. Quiring, 19

(CNC); Vancouver, 7.vii.1977, J.A. van

Reener, 52 (UBC); Southern Gulf Islands:

Galiano Island, north end, 24.vi1.1989, G.G.E.

Scudder, Cytisus scoparius, 14; Vancouver

Island: Jordan River, 27.vii.1988, G.G.E.

Scudder, C. scoparius, 14; 19 km E of Jordan

River, 27.vu1.1988, G.G.E. Scudder, C.

scoparius, 1° (CNC); Metchosin, Camas Hill

summit, 29.vii1i.—5.1x.1999, L. & C.

Rosenblood, 14, 99 (RBCM).

Field surveys. On the Lower Mainland of

BC, we found A. obsoleta in the Greater

(Metro) Vancouver area (Delta, Langley,

Lions Bay, Surrey, and West Vancouver) as far

south as the Tsawwassen community of Delta;

the plant bug also was found north of

Vancouver at Squamish and east in the Fraser

Valley at Deroche. Additional field work

probably would show that the mirid is

established farther north and east of

Vancouver than is indicated by our limited

sampling. Collections on Vancouver Island

were made from Victoria to just north of

Ladysmith. The first U.S. record is based on

the collection of late instars and adults at Point

Roberts, a small area (~12.7 km?) of

Washington State (Whatcom Co.) that is cut

off from the mainland.

We sampled broom on nearly the same

dates in both years: 26-30.vi.2010 and

22-28.vi. 2011. Populations might have been

slightly advanced in 2010, with more adults,

few of which were teneral, and fewer late-

instar nymphs compared with 2011. Earlier

instars (II-III) were observed only in 2011 at

two sites north of Vancouver. The presence of

fifth instars and teneral adults on golden chain

tree (Laburnum anagyroides), another

genistoid legume, suggests that this small

Palaearctic tree can serve as a host plant. At

all three sites where A. obsoleta was found on

L. anagyroides, broom was present within 100

m. More field work is needed to determine

whether the mirid can complete its

development on Laburnum and if this plant

association persists.

Specimens examined. CANADA: British

Columbia, Abbotsford, 49°02.387'N

122°16.306’W, 26.vi.2011, 34, 59, IV_-V;

Abbotsford, 49°03.609’'N 122°17.177'W,

27.vi.2011, 64, 29, IV—V; Delta, nr Boundary

Bay Airport, 49°04.938'N 123°00.096’W,

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

27.vi.2010, 22; Delta, Ladner, 49°05.413’N

123°02.618°W, 27.vi.2010, 34, 59,V; Delta,

Tsawwassen Ferry Causeway, 49°01.400'N

123°06.293'W, 22-23.vi.2010, 44, V;

Deroche, 49°11.454°N 122°04.062’°W, 26.vi.

2011, IV—V; Langley, 200th St. & 56th Ave.,

49°06.454’N 122°40.143’W, 28.vi.2011, 22,

12, IV-V; Lions Bay, 49°27.211'N

123°14.253' W., 27.vi.2011, 16; IV—-Ve E of

Mission, River Rd. S of Rt. 7, 49°08.919'N

122°11.018°W, 26.vi.2011, IV—V; Porteau

Point, Rt. 99, 49°32.711°'N 123°14.430'W,

27.vi.2011, II-[V; Squamish, 49°41.968'N

123°09.067'°W, 27.vi.2011, III-V; Surrey,

Guildford, 100th Ave. nr 140th St.,

49°10.994’N 122°50.195’°W, 26.vi.2010, 23,

149,V; Surrey, 16th Ave. & 192nd St.,

49°01.871'N 122°41.552’W, 28.vi.2011, 13,

IV—V; Vancouver Island, Chemainus,

48°55.701'N 123°43.257'W, 30.vi.2010, 13,

22 ex Laburnum anagyroides; Vancouver

Island, Ladysmith, Transfer Beach Park,

48°59.352°N 123°48.552’W, 30.vi.2010, 13,

2°,V; Vancouver Island, Rt. 1, 5 km N of

Ladysmith, 49°02.293'N 123°51.938'W,

28.vi.2010, 24, 69; Vancouver Island,

Saanich, Mount Tolmie Park, 48°27.449’N

23°19. 375 W, 29.vi2010, 56.50:

Vancouver Island, Victoria, Burnside Rd. W &

McKenzie Ave., 48°27.741'°N 123°24.172’°W,

29.vi.2010, 40, 59, V ex L. anagyroides;

West Vancouver, Eagle Harbour, Westport Rd.,

49°21.627°'N 123°15.463’°W, 28.vi.2010, 53,

12, V ex L. anagyroides; West Vancouver,

Marine Dr., Whytecliff Park, 49°22.297'N

123°17.426’W, 28.vi.2010, 59. UNITED

STATES: Washington, Whatcom Co., Point

Roberts, 48°58.811’N 123°04.209'°W, 24.vi.

2011, 3d’; 19, IV_V.

ACKNOWLEDGEMENTS

We are grateful to G.G.E. Scudder (Beaty

Biodiversity Centre & Department of Biology,

University of British Columbia, Vancouver)

for unpublished BC records of A. obsoleta,

with assistance from Robert A. Cannings

(RBCM, Victoria) and Michael D. Schwartz

(CNC, Ottawa), and to Leland M. Humble

(Natural Resources Canada, Canadian Forest

Service, Pacific Forestry Centre, Victoria) for

his help and hospitality in 2010. This research

was supported by the Cornell University

Agricultural Experiment Station federal

formula funds, Project No. NYC-139405 to

ERH, received from Cooperative State

Research, Education, and Extension Service,

U.S. Department of Agriculture.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011 37

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J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

SCIENTIFIC NOTE

Mortality of Metarhizium antsopliae-infected wireworms

(Coleoptera: Elateridae) and feeding on wheat seedlings are

affected by wireworm weight

WILLEM G. VAN HERK'! and ROBERT S. VERNON!

As some wireworm species are notorious

pests of common wheat, Triticum aestivum

(Vernon et al. 2009), a small study was

conducted at the Pacific Agri-Food Research

Centre (PARC) in Agassiz, BC in August

2009, to determine whether the number of

germinating wheat seedlings (cv. AC Barrie)

killed by the dusky wireworm, Agriotes

obscurus, is affected by the number and size

of the wireworms that seedlings are exposed

to. An unexpected factor appeared at the end

of the study in that many wireworms were

infected with Metarhizium anisopliae,

resulting in considerable mortality. This factor

precluded us from meeting some of the initial

objectives of the experiment, but still allowed

us to determine if mortality of seedlings was

affected by wireworm weight and number, and

if mortality of the wireworms from M.

anisopliae infection was affected by their

weight.

We filled 160 500 ml circular (dia = 11 cm,

height = 8 cm) plastic containers (Plastipak

Industries, Inc., La Prairie, QC) with 500.0

(+/- 0.2) g of soil collected from a field at

PARC, Agassiz in 2009. The soil was sieved

through a 2 mm x 2 mm screen to remove

rocks and organic material, made up to 20%

moisture by weight, and homogenized.

Containers with soil were placed in a walk-in

cooler set at 15.0 +/-0.5°C to mimic soil

temperature conditions in spring when wheat

is normally planted. Wireworms were weighed

individually on August 7, and 0-4 wireworms

were placed in each container (Table 1). All

wireworms were collected at PARC in April

2009 and stored in 401 Rubbermaid tubs

without food, at 8-10°C, until 1 wk before the

study, when tubs were brought up to room

temperature and food baits (a cup of 100 ml

moist vermiculite mixed with 10 ml wheat

seed) placed inside. Only mobile wireworms,

appearing healthy (Vernon et al. 2008) and

actively feeding 2 to 3 d prior to placement in

the containers were used for this study.

Wireworms selected ranged considerably in

weight (range: 6.6 to 46.4 mg; Table 1), but all

Wwireworms in individual containers were

similar in weight (within 5.0 mg), and an

attempt was made to have an equal number of

similar sized wireworms for each of the 1, 2,

and 3 or 4 wireworm densities to determine

the effect of wireworm weight on the number

of wheat seedlings killed.

Two days after wireworms were placed in

containers, 21 untreated wheat seeds were

planted 2 cm deep in small pre-made holes.

Seeds were spaced at equal distance (1.75 cm)

from each other, in a 3, 5, 5, 5, 3-grid pattern.

After planting, groups of eight containers were

placed in 26 cm x 47 cm x 6 cm deep nursery

flats (Eddi’s Wholesale Garden Supplies, Ltd.,

Surrey, BC), 1.01 cold water added between

the containers in the flat, and flats covered

with 14 cm high transparent plastic domes

(Eddi’s Wholesale) to prevent desiccation of

the upper layer of soil. After planting,

containers were subjected to a 12:12 light:dark

regimen.

Seedling emergence was first observed 5 d

after planting, stand counts were conducted 8

d (when domes were permanently removed

due to the length of plant shoots) and 15 d

after planting. Wireworms were removed 25 d

after planting and their health evaluated

(Vernon et al. 2008). This revealed that only

123 of 255 larvae were alive, the rest having

died from Metarhizium infection, most likely

within the first two weeks of the study as

evident from the extent of mould formation on

the surface of the cadavers. Analysis of the

proportion of wireworms dead in each

! Pacific AgriFood Research Centre, Agriculture and AgriFood Canada, P.O. Box 1000, VOM 1A0, Agassiz, British

Columbia, Canada

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Table 1.

Proportion of wheat seedlings dead or not emerging 15 days after planting. N = number of containers.

Shown are least squares means and SE estimates calculated from ANCOVA; all least squares means are

significantly different from 0 at P<0.0001.

Numbers followed by different letters in columns are

significantly different from each other at P<0.05, using a Tukey-Kramer adjustment.

No. of Wireworm Model 1: All Model 2: Surviving

wirewormsin N weight range wireworms placed N :

‘ ' ‘ wireworms alone

container (mg) in containers

0 43 0.084(0.018)A 80 0.113 (0.009) A

] 43 6.6 - 46.4 0.101(0.012)A 50 0.151 (0.012) AB

2 36 8.6 - 42.3 0.166 (0.013) B 21 0.202 (0.018) BC

3 12 25.8 - 43.7 0.233 (0.023) BC 5 0.246 (0.037) BC

4 26 8.2 - 41.3 0.250 (0.014) C 4 0.313 (0.041) C

Bee | ae F=1.18, d=19,135, F=0.97, df=19,135,

ANCOVA Flat: P=0.28 P=0.50

ae | _ F25.15, di=4,135, F=11.51, df=4,135,

Statistics No. of wireworms: P<0.0001 P<().0001

a ene: F=0.51, df=1,135, F=16.78, df=1,135,

Eee P=0.47 P<0,0001

container with ANCOVA (PROC GLM, SAS

9.1) with variable container flat and covariate

average wireworm weight in containers,

indicated that flat did not have a significant

effect (F=0.91, df=19,96, P=0.57), but

wireworm weight did (F=14.17, df=1,96,

P=0.0003). Eliminating the variable flat from

the analysis and regressing the proportion of

wireworms dead to the average wireworm

weight in each container produced the

following model: Proportion dead = 0.107 +

0.015 <x wireworm weight (SE = 0.099, 0.004;

t=1.08, 4.42; P=0.28, <0.0001, respectively;

model R* = 0.145), indicating that the

proportion of wireworms dead increased with

the average weight of wireworms in the

container.

Considering the mortality of wireworms

during the experiment, two separate analyses

were conducted to determine the effect of

Wwireworm number and weight on wheat

seedling survival. In the first analysis, the

proportion of wheat seedlings that did not

emerge by 15 d after planting was evaluated

with ANCOVA, with variables flat and the

number of wireworms originally placed in the

container, and the covariate average wireworm

weight per container (Table 1, Model 1).

Treating the number of wireworms in the

container as a variable allowed us to calculate

least squares means for the proportion of

seedlings killed per wireworm density, and

produced a similar model as when both

wireworm number and average weight were

included as covariates. The second analysis

was similar, differing only in that the number

of wireworms that survived was included.

Both models indicated that the flat in which

containers were placed did not have a

significant effect on plant mortality (P>0.05;

Table 1), and that the number of wireworms in

the container was highly significant

(P<0.0001), with the proportion of plants

killed increasing with wireworm number

(Table 1). The weight of wireworms in the

container did not appear to significantly affect

the number of plants killed if all wireworms

placed in each container were considered.

However, as heavier wireworms were more

likely to die from Metarhizium, and mortality

appeared to have occurred early in the study

when the wheat plants were most susceptible

to wireworm attack, this is probably a

misleading conclusion. When only surviving

wireworms are included in the analysis (Table

1, Model 2), it is apparent that heavier

wireworms caused more damage than smaller

ones. While this confirms the expectation that

larger wireworms are more destructive to

wheat seedlings than smaller ones, the finding

that larger wireworms are more likely to die

from Metarhizium than smaller wireworms is

novel and of importance, as it suggests that

using the fungus as a biological control agent

for wireworms may be more effective for later

than earlier instars. This relationship has

J. ENTOMOL. SOc. BRIT. COLUMBIA 108, DECEMBER 2011

apparently not been observed in wireworms

before, and should be confirmed and

explained with further study. As Metarhizium

is commonly present in Agassiz soil, all

locally collected larvae likely contain spores

and an environmental trigger (e.g. temporary

exposure to a high temperature) necessary to

induce infection. Considering the LTSO of A.

obscurus after Metarhizium infection, the

infection seen here was likely triggered prior

to wireworm placement in containers

(Kabaluk and Ericsson 2007).

ACKNOWLEDGEMENTS

We thank our summer students, Selina

McGinnis, Heike Ké6sterke, and Chantelle

Harding for helping collect and weigh

wireworms and plant wheat seeds.

REFERENCES

Kabaluk, J. T., and J. D. Ericsson. 2007. Environmental and behavioral constraints on the infection of wireworms

by Metarhizium anisopliae. Environmental Entomology 36: 1415-1420.

Vernon, R.S., van Herk, W., Tolman, J., Saavedra, H.O., Clodius, M., and B. Gage. 2008. Transitional sublethal and

lethal effects of insecticides after dermal exposures to five economic species of wireworms (Coleoptera:

Elateridae). Journal of Economic Entomology 101: 365-374.

Vernon, R.S., van Herk, W., Clodius, M., and C. Harding. 2009. Wireworm management I: Stand protection versus

wireworm mortality with wheat seed treatments. Journal of Economic Entomology 102: 2126-2136.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Symposium Abstracts: INVASION BIOLOGY!

Entomological Society of British Columbia

Annual General Meeting,

Douglas College, New Westminster, BC, Oct. 15, 2011

Climate change and invasion potential

David R. Gillespie. Agriculture & Agri-Food

Canada, Agassiz, BC

Climate change and invasive alien species

are two of the very large themes in

contemporary biology. Climate change will

clearly have impacts on the biology of

invasive species. How those impacts will

change the threats from invasive species is a

real concern. Will we cope with more invasive

species, and will those species already present

cause more injury? Some of the major trends

and ideas surrounding these questions will be

presented.

Interpreting the effects of a biocontrol

weevil released to control houndstongue

(Cynoglossum officinale) on its target weed

and a native nontarget plant.

Haley A. Catton!, Rosemarie A. De Clerck-

Floate* and Robert G. Lalonde!.

Unit of Biology and Physical Geography,

University of British Columbia Okanagan,

3333 University Way, Kelowna, British

Columbia, Canada, VIV 1V7 ?Agriculture and

Agri-Food Canada, Lethbridge Research

Centre, 5403 1°‘ Ave South, Lethbridge,

Alberta, Canada T1J 4B1

Biological control can be a very effective

way of reducing the impact of invasive plants,

and like any form of pest control includes a

risk factor. Non-target attack by a biological

control agent is undesirable, but can vary in

severity and not always outweigh the damage

the invasive host plant would inflict on an area

if left uncontrolled.

Approval for release of a weed biocontrol

Insect is contingent on strong host-specificity.

However, feeding and oviposition on related

plant species may still occur, and interpreting

and predicting this nontarget attack is an

important step in assessing potential risks in

weed biocontrol. Mogulones crucifer

(Coleoptera: Curculionidae) is a root-feeding

weevil that was approved for release in

Canada in 1997 to control houndstongue

(Cynoglossum officinale, Boraginaceae). Since

its release, M. crucifer has frequently been

successful in suppressing houndstongue, but it

also has been observed attacking native,

nontarget Boraginaceae in western Canada.

In 2009, groups of 300 M. crucifer were

released at nine rangeland sites containing the

native nontarget borage, blue stickseed

(Hackelia micrantha), either growing without

houndstongue or interspersed with the weed.

Release sites were revisited four to seven

weeks later and indications of M. crucifer

attack were observed on both plant species

within a 5 m radius of release. When plants

from three sites were harvested and dissected

10 weeks after release, M. crucifer larvae were

found in both species, but were significantly

more abundant in houndstongue (Wilcoxon

Rank Sum test, p=0.0425). Release sites were

revisited in 2010, when attack on

houndstongue continued, but indications of

nontarget attack were rare. To determine

whether nontarget attack observed in 2009

was temporary spillover, or the initial

establishment of weevils on nontargets, plants

on the 2009 release sites were harvested and

dissected in 2011 to quantify the level of

target and nontarget attack two years post

release. Preliminary results will be presented.

Recent introductions of non-indigenous

species in British Columbia

LM Humble!, MK Noseworthy!, JR

deWaard? and T. Hueppelsheuser*

'Natural Resources Canada, Canadian Forest

Service, Victoria BC *Biodiversity Institute of

Ontario, Guelph ON ?Royal British Columbia

Museum, Victoria, BC *British Columbia

Ministry of Agriculture, Abbotsford, BC

Recent establishments of invasive insect

pests such as the emerald ash borer, Asian

long-horned beetle and brown spruce longhorn

beetle in Canada have highlighted the threat

that such incursions pose to the urban and

natural forests of the country. The impacts of

non-indigenous introductions generally first

occur in urban environs, as a direct

consequence of the importation of a wide

range of commodities. Once established in the

urban environments, pest populations can

expand into the adjacent natural forests. We

provide a brief introduction to two pathways

for the introduction of non-indigenous species

of significance to forestry. The generic

composition of the urban trees planted in

Vancouver is reviewed and results of various

surveys of the insect fauna associated with the

urban forests are presented.

More than twenty-five non-indigenous

herbivores have been discovered in British

Columbia during inventories of the fauna of

urban parks and street trees or during the

construction of DNA reference libraries for

species identification. They include: eight

species of Lepidoptera; seven sawflies

(Hymenoptera: Symphyta); ten beetles

(Coleoptera: Cuculionidae and Cerambycidae)

and one gall midge (Diptera: Cecidomyiidae).

The hosts and the feeding guilds,

overwintering biology, life histories, and

native and introduced ranges of these

introductions are examined and a preliminary

analysis of the probable pathways for their

introduction is presented. Evidence for the

expansion into natural forest habitats are

presented for some species. Canadian and

international strategies to prevent the influx of

alien invasive species are discussed.

Policy, regulation and invasives: role of

CFIA

Gabriella Zilahi-Balogh Canadian Food

Inspection Agency, Kelowna, BC

The Canadian Food Inspection Agency

(CFIA) has a long history of mitigating pest

introductions resulting from international

trade. With increasing trade and increasing

movement of plant products internationally,

invasive alien species are an immediate and

growing threat to Canada's environment and

economy. The mandate of the plant health

program within CFIA is to protect plant health

and production in Canada by preventing the

introduction and spread of quarantine pests

that threaten Canada's agriculture, forestry and

horticultural resources through science based

regulation and enforcement. Examples of

measures used to mitigate the introduction and

spread of regulated pests into Canada will be

provided using the grape industry as an

example.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

The European fire ant (Myrmica rubra) in

British Columbia

Robert Higgins Thompson Rivers University,

Kamloops, BC

The identification of the European fire ant

(Myrmica rubra) in North Vancouver in the

fall of 2010 marks the first determination of

this pest ant west of southern Ontario, in

Canada, and above 49°N latitude in North

America. Since this first identification, this ant

has also been confirmed in Burnaby,

Vancouver, and Victoria. The European fire

ant is anthropogenic, most likely being

introduced in landscaping plants and then

spreading densely through lawns, raised

garden beds, small homeowner cold-frames

and greenhouses. This ant swarms rapidly

when disturbed (e.g., lawn mowing) and,

unlike most ant species in BC, readily and

noticeably stings. In this presentation, the

introduction of this species to North America

will be reviewed. The natural history of this

ant will be discussed, especially where this

differs from that of its native range, and helps

to explain the manner in which colonies

spread once established. Further, management

strategies will be considered, particularly in

the context of urban neighbourhoods.

Spotted wing Drosophila (Drosophila

suzukii): Update for coastal British

Columbia, Oct 15, 2011.

Tracy Hueppelsheuser British Columbia

Ministry of Agriculture

Spotted wing Drosophila (Drosophila

suzukii, SWD) has been present in British

Columbia fruit growing areas and the Western

United States since 2009. SWD is a temperate

fruit fly, which infests ripening fruit before

harvest. Infested fruit is not unmarketable.

SWD infests a wide range of thin-skinned fruit

including blueberries, strawberries,

raspberries, blackberries, cherries and grapes.

There are several non-crop hosts of SWD

in BC; the primary concern in coastal BC is

Himalayan blackberry Rubus discolor.

2011 Fraser Valley trapping results indicate

that the SWD population was lower and later

than in 2010. In 2011, presence of larvae in

harvested fruit was not detected until mid

August, compared to late July in 2010.

Harvested raspberry and blueberry fruit

can be evaluated for larval infestation by

submerging a known amount of fruit in a

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

solution of sugar or salt of adequate

concentration.

SWD flies were caught throughout the

winter of 2010/11, with the highest catches in

hedgerows — unmanaged mixed vegetation

adjacent to commercial fields. The lowest

catches were at building sites. Trap catches

dropped considerably after January, and

remained low to nil through the spring. Flies

caught from January onward were mostly

female.

Spotted wing Drosophila in the southern

interior valleys of British Columbia,

2010-2011

Acheampong, S.!: Thistlewood, H.?, Leaming,

C.3, Thurston, M.*, Krahn, G.°, & Holder, D.®

' Ministry of Agriculture, Kelowna, BC,

Canada “Agriculture and Agri-Food Canada,

Pacific Agri-Food Research Centre,

Summerland, BC, Canada Okanagan Tree

Fruit Cooperative, Penticton, BC, Canada

4Okanagan Tree Fruit Cooperative, Kelowna,

BC, Canada °Okanagan Tree Fruit

Cooperative, Vernon, BC, Canada °Farmquest

Consulting Ltd., Creston, BC, Canada

Spotted wing drosophila, Drosophila

suzukii, was first detected in the interior of

British Columbia in September 2009. Adult

populations were monitored with extensive

networks of apple cider vinegar-baited traps in

2010 and 2011. In 2010, D. suzukii was

widespread in the Okanagan and Similkameen

valleys, present in the Creston Valley, and

damage was reported in cherry, peach,

nectarine, apricot and berry crops as well as

domestic small fruit. In 2011, lower

population levels were recorded in the

Okanagan and Similkameen valleys than in

2010, none was found in the Creston valley

and there were no reports of economic damage

in commercial fruit. New hosts recorded in the

southern interior valleys of B. C. to date are

Oregon grape, blue elderberry, northern black

currant, honey suckle, Mahaleb cherry and

ornamental elderberry.

Presentation Abstracts

Entomological Society of British Columbia

Annual General Meeting,

University of the Fraser Valley, Abbotsford, BC, Oct. 14, 2011

Olfactory responses of Micromus variegatus

(Neuroptera: Hemerobiidae) to pepper

leaves infested with Myzus persicae and

Aulacorthum solani (Homoptera:

Aphididae).

Rob McGregor & Chloé Hemsworth Jnstitute

of Urban Ecology, Douglas College

Micromus variegatus (Neuroptera:

Hemerobiidae) is being evaluated for

biological control of pest aphids on

greenhouse-grown peppers in BC. Responses

of adult females to the odours of pepper leaves

infested with Myzus persicae and

Aulacorthum solani (Homoptera: Aphididae)

were conducted using y-tube olfactometers.

M. variegatus females show a slight

preference for the odour of M._ persicae-

infested leaves vs. clean plant odours. No

similar preference was recorded for the odour

of A. solani-infested leaves vs. clean plant

odours. Results are discussed as they relate to

the use of MZ. variegatus for biological control

of M. persicae and A. solani in BC pepper

greenhouses.

Cryptic diversity of a candidate weed

biological control agent

Chandra E. Moffat, Robert G. Lalonde &

Jason Pither Department of Biology,

University of British Columbia, Kelowna BC

We surveyed host plant use of a candidate

weed bio-control agent (a gall wasp), for

invasive hawkweeds, in its native range of

Central Europe. Despite gall occurrence on

multiple host species, when suitable species

co-occurred we found that host use was

significantly non-random, with only the most

abundant species being utilized.

Update on Balsam woolly adelgid in BC

Gabriella Zilahi-Balog Canadian Food

Inspection Agency, Kelowna, BC

The balsam woolly adelgid was

accidentally introduced into North America

from Europe in the early 1900s. It is a pest of

Abies sp. and infested trees have reduced

vigor, growth that can eventually result in tree

mortality. This pest is regulated both

provincially and federally. The history of

balsam woolly adelgid in BC, biology,

regulations and recent detections outside the

current quarantine zone will be discussed.

Cool Caterpillars: Low Temperature

Biocontrol of A Climbing Cutworm

T. Scott Johnson!, Tom Lowery’, Joan

Cossentine*, and Jenny Cory! ‘Department of

Biological Sciences, Simon Fraser University,

8888 University Drive. Burnaby, BC, V5A 1S6

Canada AAFC, Pacific Agriculture Research

Centre, 4200 Highway 97, Summerland, BC

VOH 1Z0 Canada.

Abagrotis orbis is a climbing cutworm pest

in the vineyards of the Okanagan. Much of

their active feeding periods occur under cooler

temperatures. We evaluated their susceptibility

to several entomopathogenic fungi and

nematodes across three temperatures. The

larvae were susceptible to entomopathogenic

fungi and nematodes with the highest

mortality rates occurring at higher

temperatures, though significant mortality

took place at lower temperatures.

Resistance to Bacillus thuringiensis alters

macronutrient selection, regulation and

utilization in the cabbage looper,

Trichoplusia ni: Effects on performance

and disease resistance

Ikkei Shikano and Jenny Cory Department of

Biological Sciences, Simon Fraser University

Nutritional qualities of host plants affect

both insect performance and condition.

Previous studies have shown that Bt-resistant

Trichoplusia ni exhibit significant

developmental costs when reared on certain

host plants. We examined whether susceptible

and Bt-resistant [ni select, regulate and use

macronutrients differently, and how such

differences may influence performance and

susceptibility to Bt challenge.

The influence of natal host on the fecundity

of the parasitoid, Praon unicum, on the

blueberry aphid, Ervicaphis fimbriata

Erfan Vafaie!, Sheila Fitzpatrick’, Jenny Cory!

'Department of Biological Sciences, Simon

Fraser University, 8888 University Drive.

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Burnaby, BC, V5A 1S6 Canada *AAFC,

Pacific Agriculture Research Centre, 4200

Highway 97, Summerland, BC VOH 1Z0

Canada.

We studied the effects of rearing Praon

unicum on an alternative host, Myzus

persicae, on its ability to parasitize novel

aphid hosts. A combination of potential/

realized fecundity, and fitness proxies were

used to determine the impact of an alternative

host and are discussed in the context of

augmentative control.

Identifying feeding attractants from showy

milkweed flowers for potential control of

the apple clearwing moth

Eby, C!; Gardiner, M?; Gries, R!; Judd, G?;

Gries, G! ‘Simon Fraser University,

Department of Biological Sciences, Burnaby,

BC Pacific Agri-Food Research Centre,

Summerland, BC

Adult Synanthedon myopaeformis, an

exotic pest of apples in BC, commonly feed

on showy milkweed flowers. Candidate

feeding attractants captured using floral

headspace analyses were identified using GC-

EAD and proboscis extension assays. A single

chemical was shown to be highly attractive to

both males and females in field trapping

assays.

Supporting Butterfly Conservation in

British Columbia: The BC Butterfly Atlas

Patrick Lilley Raincoast Applied Ecology,

Vancouver, BC

Mapping biodiversity information is

invaluable for the conservation of species and

their habitats. Involving citizens can extend

the reach of survey projects while also making

nature more accessible and fun. Following on

the success of the BC Breeding Bird Atlas and

butterfly atlassing projects in other

jurisdictions, the BC Butterfly Atlas is a multi-

year effort to inventory and assess the status

of butterflies in British Columbia. The BC

Butterfly Atlas aims to establish a network of

observers to observe, record, and report

butterfly sightings from across the province.

Results will be combined with existing

butterfly records to create an online atlas

documenting the distribution of butterflies in

BC. Like the Breeding Bird Atlas,

participation from a broad range of volunteer

observers, from amateurs to experts, will be

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

key to the success of the project. This talk will

introduce the elements of the BC Butterfly

Atlas project and discuss opportunities for

participation and involvement.

Estimating the impact of arthropod

predators preying upon lygus nymphs in

the Peace River region of Canada.

Letitia Da Ross & Jennifer Otani Agriculture

& Agri-Food Canada, Beaverlodge Research

Farm, Beaverlodge, AB

Lygus bugs are native pests that are often

found in abundance, feeding on canola buds

and pods. To estimate potential predation

pressure on lygus, four general predators were

collected from fields in 2010, then isolated

with 34, 4% and 5 instar lygus nymphs. The

prey preference results of these predators will

be presented.

Group morphology affects foraging success

in social spiders

Maxence Salomon Biodiversity Research

Centre, UBC, Vancouver

Social spiders that build communal webs

may rely on the architectural properties of

their webs to achieve foraging success. I

conducted a field experiment to examine

foraging dynamics in two social species of

Anelosimus spp. spiders that vary in individual

and group morphology, and show that

foraging success depends both on the

functional morphology of their communal

webs and individual cooperative behaviours.

Update on a few insect species at risk

initiatives in British Columbia

Jennifer Heron British Columbia Ministry of

the Environment, 315 — 2202 Main Mall,

Vancouver, BC, Canada V6T 1Z1

Insect conservation is one of the greatest

challenges to conservation practitioners.

Assessing the conservation status of insect

species is more challenging than other species

groups, primarily because so little information

is available on individual species. Assessing

the conservation status involves a number of

criteria developed by Natureserve

(www.natureserve.org) and the BC

Conservation Data Centre

(www.env.gov.bc.ca/cdc). Some of the

information used to assess a species’

conservation status includes 1) inventory and

search effort (e.g., including search effort with

no records); 2) species information; 3)

provincial, national and global distribution; 4)

associated habitat and habitat trends including

historic habitat trends and whether the species

is associated with an ecosystem at risk; 5)

biology and natural history; 6) population

sizes And trends; 7) limiting factors and

threats; 8) special significance of the species;

9) existing protection including both

legislative protection and other status

designations; and 10) collections examined. In

some instances, a status report is prepared at

the provincial level or at national level and

incorporates this above information as well as

other details about the species.

The Committee on the Status of

Endangered Wildlife in Canada (COSEWIC)

is the national committee that assesses

whether a species should be recommended for

listing under the federal Species At Risk Act

(SARA) (www.cosewic.gc.ca). To assist

COSEWIC status report writers (e.g., provide

more information on three insect species

currently having national status reports

prepared), targeted surveys for three insect

species were completed in 2010/11: Wester

Bumblebee (Bombus occidentalis), Audouin’s

Night-stalking Tiger Beetle (Omus audouini)

and Western Branded Skipper (Hesperia

colorado oregonia).

Once a species has been assessed by

COSEWIC and listed under the Species At

Risk Act (SARA) as extirpated, endangered,

threatened or special concern the responsible

jurisdiction (e.g., British Columbia) prepares a

recovery strategy or management plan that

outlines a plan for recovery. The recovery

strategy follows science advice given by a

group of individuals under a recovery team.

Recovery team members include

representatives from local stewardship groups,

landowners and lands managers, government

staff from all levels, researchers and private

citizens interested in conservation of the

species.

Individuals interested in the recovery of

species at risk are encouraged to contact the

recovery team chair and either engage in

participating on the recovery team or suggest

how they would like to become involved or

lead recovery actions for the species.

Recovery actions are most often linked with

reducing threats to the species (e.g., removal

of invasive plants that may be contributing to

a decline in host plant growth for a specific

butterfly), habitat restoration or studying the

species’ life history. Recovery actions also

link closely with stewardship and _ local

conservation groups, as well as other recovery

teams in order to avoid conflicts with recovery

actions for other species.

The challenges surrounding invertebrate

conservation and the path forward involve

engaging numerous agencies, groups, and

incorporating initiatives into existing

infrastructure. A present provincial

invertebrate conservation plan is being

drafted, which outlines a broad approach to

protecting this species group throughout the

province. Part of the recommendations within

this plan involves engaging stakeholders and

others interested in invertebrate conservation

into being part of recovery teams, writing

status reports on species they think are

possibly at risk, educating people on insect

identification and encouraging people to

submit records and sightings to the BC

Conservation Data Centre. Those interested

are encouraged to contact the presenter about

how they can contribute to provincial

invertebrate conservation initiatives.

Aphid mummies provide parasitoids with a

temporal refuge from predation by

ladybird Harmonia axyridis

F. Simon! and D. Gillespie? ‘Simon Fraser

University *Agriculture and Agri-Food

Canada *University of the Fraser Valley

Harmonia axyridis is a predatory ladybird,

which consumes aphids and parasitoids. This

study demonstrates that parasitoid mummies

are a refuge from predation. Additionally, H.

axyridis has differential preference for

Aphidius matricariae over Praon unicum.

Consequences of H. axyridis’ preference will

be discussed in the context of biological

control and impacts for native aphid-parasitoid

systems.

The effects of experience on intermale

competition in the western black widow

spider

Tanya L.M. Stemberger!?, Maria Modanv’,

Maydiannce C.B. Andrade? ‘Department of

Biological Sciences, Simon Fraser University

?Department of Biological Sciences,

University of Toronto Scarborough

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

Understanding factors affecting multiple

mating by males is critical to assessment of

the intensity of sexual selection. We asked

whether males with mating experience suffer a

decrease in the likelihood of future matings in

the western black widow spider (Latrodectus

hesperus). Males of this species largely cease

eating after adulthood, and so have a limited

energetic budget for mate searching, courtship

and competition. Mating includes a six-hour

long, energetically expensive courtship, and at

copulation a portion of the male’s genitalia

breaks off in the female's reproductive tract.

Although sexual cannibalism is rare and L.

hesperus males are physically able to copulate

with multiple females, we predicted mating

would decrease a male's resource holding

potential and the likelihood of remating under

competition. We paired once-mated males

with size-matched virgin rivals and allowed

them to compete for a female. Contrary to

predictions, once-mated males won

copulations as effectively as their virgin rivals,

despite the prior loss of energy to intense

courtship and genital trauma. Moreover, in all

cases, only one male out of every pair

copulated with the female. This suggests

mating success may be mediated by female

preferences rather than inter-male

competition, which may explain why

experienced males suffer no disadvantage.

Entomological biocontrol agents of illicit

drug plants

Adrian L. Behennah /829 Laval Avenue,

Victoria, BC Canada VSN 1M9

Herbivores of the botanical sources of

heroin, cocaine, and marijuana were

researched by the UN and the USA during the

past 40 years for use as biocontrol agents,

including the poppy capsule weevil,

Ceutorhynchus (Neoglocianus) maculaalba;

cocaine tussock moth, Eloria noyesi

(Lepidoptera: Noctuidae); and hemp flea

beetle, Psylliodes attenuata (Coleoptera:

Chrysomelidae).

A century of outbreaks: tracking the

western spruce budworm in BC

Lorraine Maclauchlan Ministry of Forests,

Lands and Natural Resource Operations,

Kamloops, BC

The story of western spruce budworm

(WSB), Choristoneura occidentalis Freeman,

J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011

in British Columbia reflects the changing

climatic and human patterns observed this past

century in Douglas-fir, Pseudotsuga menziesii,

dominated forest environments. WSB has less

predictable population fluctuations than other

defoliating insects, with outbreaks lasting

several years or collapsing after only one to

two years. Based upon analysis of stand

structure, geographic and topographic

features, ecosystems and defoliation history,

twelve distinct outbreak regions have been

defined. Within these geographic outbreak

regions the periodicity of budworm outbreaks

is described. BC has records of budworm

outbreaks going back to 1909 that help

illustrate population fluctuations. The first

recorded outbreaks occurred on Vancouver

Island in the early 1990s yet no outbreaks

have since occurred on the island. Thomson

and Benton (2007) attribute the cessation of

WSB outbreaks on Vancouver Island as

possibly due to warming sea temperatures that

promote early larval emergence and thus poor

synchrony between insect and host tree. Since

the 1930s all WSB outbreaks have occurred in

the interior of BC. The Coast Region has

experienced very regular, periodic budworm

outbreaks since 1940 but the scale of

outbreaks has decreased over the past two

outbreak cycles. The dry canyon forests near

Lillooet have the longest and most regular,

chronic, outbreak cycles with five distinct

outbreaks in the past century. Each outbreak

ranged from a few thousand, to over a hundred

thousand hectares of annual defoliation.

Although budworm can occur in most

Douglas-fir dominated ecosystems, there are

still some areas where there appears to be no

history of WSB outbreaks.

Budworm is present at low levels in most

susceptible forest types. However these insect

populations may or may not be able to reach

what we define as outbreak proportions unless

certain stand conditions are met or some

biological or physiological triggers occur. In

2006 Maclauchlan eft al. reported that there

were large areas or susceptible forest type in

south and central BC, such as the Cariboo-

Chilcotin, where WSB had never reached

outbreak levels. The Thompson Okanagan has

seen large, often sustained outbreak periods,

but these have all occurred within the past

three decades. Prior to the 1970s the budworm

seldom reached outbreak levels in this region.

Budworm was first mapped in the Cariboo

Region in 1974 but only over a small area and

no outbreaks were recorded until the late

1990s. Once the budworm population

expanded it spread rapidly, mingling with

existing endemic populations throughout the

Cariboo-Chilcotin. The Cariboo budworm

outbreak is one of the largest and most

sustained outbreaks ever recorded in BC. The

most recent chapter in the budworm saga now

has populations expanding north between

Williams Lake and Quesnel and into the

Kootenay Boundary Region in southern BC.

The Quesnel outbreak marks the most

northern outbreak yet recorded. Similarly,

outbreak populations built in the Princeton

and Merritt areas in the past decade where

historically there also had been few or no

records of outbreak level populations.

The WSB is reacting to our changing

climate and increasingly favourable and

available host resource. Current budworm

outbreaks are distinguished by their expansion

into higher elevations and new territory. This

change in outbreak dynamics is a response by

the insect to milder, more suitable climatic

conditions; altered stand conditions; and

forests that have little inherent resistance to

this insect. As the climate warms, budworm

may continue to expand in range toward the

limit of its primary host, Douglas-fir.

Maclauchlan, L.E., J.E. Brooks and J.C. Hodge. 2006.

Analysis of historic western spruce budworm

defoliation in south central British Columbia.

Forest Ecology Management 226: 351-356.

Thomson, A.J. and R.A. Benton. 2007. A 90-year sea

warming trend explains outbreak patterns of

western spruce budworm on Vancouver Island.

The Forestry Chronicle 83(6): 867-869.

NOTICE TO CONTRIBUTORS

The JESBC is published once per year in December and articles are also published online as they are

accepted. The JESBC is an open-access journal. Manuscripts dealing with all facets of the study of

arthropods will be considered for publication provided the content is of regional origin, interest, or

application. Authors need not be members of the Society. Manuscripts are peer-reviewed, a process that

takes about six weeks.

Submissions. The JESBC accepts only electronic submissions. Submit the manuscript in MS Word

along with a cover letter, as an e-mail attachment to the Editor. Manuscripts should be 12-point font,

double-spaced with generous margins and numbered lines and pages. Tables should be on separate,

numbered pages. Figure captions should be placed together at the end of the manuscript. Each figure

should be submitted as a separate electronic file. Figure lines should be sufficiently thick and lettering

sufficiently large so that they are clear when reduced to fit on the Journal page, 12.7 x 20.5 cm.

Preferred graphic formats are GIF and JPG at least 1500 pixels wide. Do not send raw (uncompressed)

files such as TIFF or BMP.

Submission deadline for Vol. 109 is September 1, 2012. Submit contributions to:

Dr. Dezene Huber, (Editor-in-Chief) huber@unbc.ca

Ecosystem Science and Management Program

University of Northern British Columbia

3333 University Way

Prince George BC V2N 4Z9

Canada Tel: 250-960-5119

Style and format. Consult the current volume for style and format. Style generally conforms to the

Entomological Society of America Style Guide, available at http:// www.entsoc.org/pubs/publish/style/

index.htm. Pay particular attention to the formats of References Cited. If there is no precedent, consult

Scientific Style and Format: The CBE Manual for Authors, Editors, and Publishers, 6th Ed., published

by the Council of Biology Editors.

Scientific Notes are an acceptable format for short reports. They must be two Journal pages maximum,

about four manuscript pages. Scientific Notes do not use traditional section headings, and the term

"Scientific Note" precedes the title. A short abstract may be included if desired. Notes are peer-

reviewed in the same manner as regular submissions.

Page charges. The Society has no support apart from subscriptions. The page charge for articles is $35

and includes all tables and figures except coloured illustrations. The page charge is $40 if none of the

authors are members of the ESBC. A substantial surcharge for coloured illustrations applies.

Page charge waiver. Authors whose entomological activities are not supported by universities or

official institutions, who are unable to pay page charges from their personal funds, may apply for

assistance when submitting a manuscript.

Electronic reprints. The Society provides authors with an Adobe Acrobat file of an exact copy of the

paper as it appears in the Journal. This file will also be posted on the ESBC Website (http://www.sfu.ca/

biology/esbc/) to provide free electronic access to our Journal for all interested parties.

Back issues. Back issues of many volumes of the Journal are available at $15 each.

Membership in the Society is open to anyone with an interest in entomology. Dues are $30 per year

for domestic memberships, $20 for students, and $35 for international memberships. Members receive

the Journal, Boreus (the Newsletter of the Society), and when published, Occasional Papers.

Address inquiries to:

Dr. Lorraine Maclauchlan, Treasurer lorraine.maclauchlan@gov.bc.ca

B.C. Ministry of Forests, Lands and Natural Resource Operations

441 Columbia St

Kamloops, BC Tel: (250) 828-4179

Canada, V2C 2T3 Fax: (250) 828-4154

TITUTION LIBR

= mec

Entomological Society of British Columbia

Volume 108 Issued December 2011 ISSN #0071-0733

Directors of the Entomological Society of British Columbia, 2011-2012................ 2

L. Camelo, T.B. Adams, P.J. Landolt, R.S. Zack and C. Smithhisler. Seasonal

patterns of capture of Helicoverpa zea (Boddie) and Heliothis phloxiphaga

(Grote and Robinson) (Lepidoptera: Noctuidae) in pheromone traps in

Washington State: :....c...00l.00ccis ce senaeannce uetenhtensanaedce lentes Suen ise ata ea ae 3

E. Miliczky and D.R. Horton. Occurrence of the Western Flower Thrips,

Frankliniella occidentalis, and potential predators on host plants in near-

orchard habitats of Washington and Oregon (Thysanoptera: Thripidae)............ 11

G.G.E. Scudder, L.M. Humble and T. Loh. Drymus_ brunneus (Sahlberg)

(Hemiptera: Rhyparochromidae): a seed bug introduced into North

AMET ICA. a. coc scceseey nnvdeton'sdaccceaeeuneneas ese doelles ive Bletel gee M ie ane eee 29

A.G. Wheeler, Jr. and E.R. Hoebeke. Asciodema obsoleta (Hemiptera: Miridae):

New Records for British Columbia and First U.S. Record of an Adventive Plant

Bug of Scotch Broom (Cytisus scoparius; Fabaceae)...........c:ccccsssccceessreeeeneeees 34

NOTES

W.G. Van Herk and R.S. Vernon. Mortality of Metarhizium anisopliae infected

wireworms (Coleoptera: Elateridae) and feeding on wheat seedlings is affected

by wire worm Weight.......50c0:c0iesccas-aveddecceeadescatndecneWieasees ase -tacepeneene get ee eee 38

ANNUAL GENERAL MEETING ABSTRACTS

Symposium Abstracts: Invasion Biology!. Douglas College, New Westminster,

B.C., Oct..15, 2011 sco oc este ace ae iene cece ee 42

Entomological Society of British Columbia Annual General Meeting Presentation

Abstracts. University of the Fraser Valley, Abbotsford, B.C., Oct. 14, 2011.....44

NOTICE TO THE CONTRIBUTORS. ....0....0. oc ececceeeeeeteees Inside Back Cover