Updated 01/16/09

Eric H. LaGasa¹, Todd A. Murray², Mark Hitchcox³, and Amberlynn Pauley-Cawley³

Background

In recent years, insect surveys conducted by the Washington State Department of Agriculture (WSDA) and funded by the USDA Animal and Plant Health Inspection Service (APHIS) Cooperative Agricultural Pest Survey (CAPS) program have detected a number of exotic species of defoliating moth pests (Lepidoptera) in Western Washington State. Several of the exotic species finds represent first record of the pest in the United States, having migrated into Washington from adjacent areas of British Columbia, Canada, where they were likely first introduced into North America. In one case, the exotic pest detection was the first record for the species in North America.

Most of the new exotic pests were likely introduced into the region within the last 20 to 40 years and are now unfortunately well established here. Some may eventually impact diverse northwest economic and environmental interests, including commercial nurseries, row crops, fruit tree production, private and commercial landscape management, and industries which rely on healthy native plant communities such as timber and tourism. For almost all of the exotic newcomers, their modes of entry into North America are unknown.

Exotic plant pests found in Washington State since 1985, year found, and detection status include:

apple ermine moth (Yponomeuta malinellus Zeller) - 1985, New to United States
apple tortrix (Archips fuscocupreanus Walsingham) - 1995, New to North America
apple skeletonizer (Swammerdamia pellicaria (Retz.) - 1994, New to United States
barred fruit tree tortrix (Pandemis cerasana (Hubner)) - 1994, New to United States
cherry bark tortrix (Enarmonia formosana Scopoli) - 1991, New to United States
cherry ermine moth (Yponomeuta padellus L.) - 1993, New to United States
dark fruit tree tortrix (Pandemis heparana (D & Schif)) - 1994, New to United States
European emerald (Hemithea aestivaria (Hubner)) - 1995, New to United States
'golden' leaf roller (Croesia holmiana (L.)) - 1994, New to United States
green budworm (Hedya nubiferana (Haworth)) - 1994, New to Western U.S.
green pug moth (Chloroclystis rectangulata (L.)) - 1994, New to Western U.S.
lesser budmoth (Recurvaria nanella (Hubner)) - 1994, New to Western U.S.
oak skeletonizer (Carcina quercana (Fabricius)) - 1997, New to United States
rose shoot borer (Notocelia rosacolana Doubleday) - 1996, New to United States
straw-colored tortrix (Clepsis spectrana (Treitschke)) - 1998, New to United States

Many of these new species were reared to adult from field collected larvae during several CAPS surveys and any parasitoids present were kept for future analysis. This survey is largely an analysis of that compiled parasitoid material. Parasitoid predation is a key factor in determining whether introduced exotic species become significant economic pests here.

1999 Project Objectives

1. Identify parasitoids reared from identified exotic defoliator larvae.

2. Summarize parasitoid/host associations and determine parasitoid prevalence (e.g. percent parasitism observed).

Project Methods and Results

Parasitoid and Host Identification

Defoliating lepidopteran larvae and pupae were collected from various target areas in Western Washington and reared on either artificial diet or host plant foliage to emergence of the adult moth or parasitoid(s). (See full report for details)

Associated parasitoids were sent to identifier specialists contracted for the purposes of this survey. Braconidae specimens were identified by Dr. Michael J. Sharkey, at the University of Kentucky, and Ichneumonidae specimens were identified by Dr. David Wahl, at the American Entomological Institute.

Due to needed revisions in several large taxonomic groups of parasitoids and poorly known groups, not all parasitoids were identifiable to the species level. However, all specimens were identified to genus, and discrete species were sorted to designated species numbers (i.e. species 1, species 2, etc.).

Defoliator larvae collected and reared for identification and parasitoid analysis in WSDA surveys represented a cross section of larval sampling from many plants, although the majority were from apple trees. Apple was the exclusive host-target of 1994/1995 survey (LaGasa et. al. 1996)

Overall, defoliator species identified from reared adults included some of the exotic species listed in the background section of this report, as well as other exotic species long established here and a few native species. Parasitoids reared from historically introduced exotic and native defoliator species were also identified in this survey to detect exotic parasitoid species possibly introduced with the exotic defoliators.

A total of 261 parasitoid specimens were identified in this survey, comprising 46 parasitoid species reared from 14 species of defoliator.

At least one exotic parasitoid species, a European species not previously recorded in North America, was identified in this survey - Hormius radialis Telenga (Braconidae: Hormiinae) reared from a native defoliator, Choristoneura rosaceana, the oblique-banded leafroller.

Additionally, one apparent undescribed species was found in the reared material, a Charitopes n. sp. - D. Wahl det. (Ichneumonidae: Cryptinae: Phygadeuontini), reared from an indeterminable species of Yponomeutidae.

In the interest of providing identification resources for pest control operators and others involved in managing the impacts from defoliating pests in the Pacific Northwest, graphic images of most of the more prominent parasitoid species listed in the preceding tables are provided in the subsequent portions of this report. (See image use and distribution note at end of document) Pictured species are those identified to the species level and/or were found to be parasitizing significant economic exotic species new to the region.

A summary of the records for defoliator larvae reared during CAPS surveys since 1994 is presented in Table 3. Note that the percent parasitism shown is provided for discussion purposes and is calculated relative to the number of total rearing records shown. For a few defoliator species the total number of rearing records shown is fairly inclusive, and the overall rate of parasitism (% Parasitism) approximates rates observed in the field (A. rosanus, C. pariana, and C. holmiana). However, for most species the total number of all larvae reared is not available, thus the parasitism rates shown are inflated to some degree and are not significant.

Parasitoid Species Identified and Host Records Apanteles aristoteliae Viereck (Braconidae: Microgastrinae) Host Species Number Records Archips rosanus (L.) European leafroller 1 Argyrotaenia franciscana (Wlsm) orange tortrix 4 Choristoneura rosaceana (Harris) oblique-banded leafroller 1 Apanteles polychrosidis Vrk. (Braconidae: Microgastrinae) Host Species Number Records Archips rosanus (L.) European leafroller 2 Choristoneura rosaceana (Harris) oblique-banded leafroller 1 Spilonota ocellana (Den. & Schff.) eye-spotted bud moth 2 Apanteles xanthostigma Haliday (Braconidae: Microgastrinae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 5 Archips rosanus (L.) European leafroller 1 Pandemis heparana (Dns. & Schff.) dark fruit-tree leafroller 1 Ascogaster quadridentata Wsml. (Braconidae: Cheloninae) Host Species Number Records Spilonota ocellana (Den. & Schff.) eye-spotted bud moth 1 Charitopes n. sp. (D. Wahl det.) (Ichneumonidae: Cryptinae) Host Species Number Records Yponomeuta sp. (prob.) 1 Charmon cruentatus Haliday (Braconidae: Holobinae) Host Species Number Records Choristoneura rosaceana (Harris) oblique-banded leafroller 2 Croesia holmiana (L.) 'golden' leafroller 1 Diadegma sp. 1 (Ichneumonidae: Campopleginae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 5 Archips rosanus (L.) European leafroller 4 Choristoneura rosaceana (Harris) oblique-banded leafroller 9 Croesia holmiana (L.) 'golden' leafroller 1 Pandemis sp. 2 Diadegma sp. 2 (Ichneumonidae: Campopleginae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 20 Archips rosanus (L.) European leafroller 12 Choristoneura rosaceana (Harris) oblique-banded leafroller 10 Choreutis pariana apple and thorn skeletonizer 12 Pandemis heparana (Dns. & Schff.) dark fruit-tree tortrix 2 Spilonota ocellana (Dns. & Schff.) eye-spotted bud moth 2 Diadegma sp. 3 (Ichneumonidae: Campopleginae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 1 Choristoneura rosaceana (Harris) oblique-banded leafroller 1 Croesia holmiana (L.) 'golden' leafroller 2 Dolichogenidea clavata (Prov.) (Braconidae: Microgastinae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 1 Archips rosanus (L.)  European leafroller 1 Dolichogenidea longicauda (Wes.)(Braconidae: Microgastinae) Host Species Number Records Choreutis pariana (Clerck) apple and thorn skeletonizer 2 Pandemis heparana (Dns. & Schff.) dark fruit-tree tortrix 1 Gelis sp. (Ichneumonidae: Cryptinae) Note: a Hyperparasitoid Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 2 Archips rosanus (L.) European leafroller 2 Choreutis pariana (Clerck) apple and thorn skeletonizer 2 Coleophora seratella (L.) cigar case-bearer 1 Hormius radialis Telenga (Braconidae: Hormiinae) Note: First Record for North American (a European species) Host Species Number Records Choristoneura rosaceana (Harris) oblique-banded leafroller 1 Ischnus inquisitorius (Muller) (Ichneumonidae: Cryptinae) Host Species Number Records Archips rosanus (L.) European leafroller 1 Choristoneura rosaceana (Harris) oblique-banded leafroller 6 Pandemis sp. (prob. heparana) dark fruit-tree leafroller 1 Itoplectis quadricingulata (Prov.) (Ichneumonidae:Pimplinae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 1 Archips rosanus (L.) European leafroller 5 Choristoneura rosaceana (Harris) oblique-banded leafroller 2 Croesia holmiana (L.) 'golden' leafroller 1 Enarmonia formosana (Scop.) cherry bark tortrix 1 Pandemis heparana (Dns. & Scff.) dark fruit-tree tortrix 1 Pandemis sp. (prob. heparana) 2 Macrocentrus linearis (Nees) (Braconidae: Macrocentrinae) Host Species Number Records Choristoneura rosaceana (Harris) oblique-banded leafroller 1 Meteorus trachynotus Viereck (Braconidae: Meteorinae) Host Species Number Records Archips rosanus (L.) European leafroller 1 Choristoneura rosaceana (Harris) oblique-banded leafroller 5 Microgaster epigoges Gahan (Braconidae: Microgastrinae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 3 Archips rosanus (L.) European leafroller 7 Choristoneura rosaceana (Harris) oblique-banded leafroller 24 Spilonota ocellana (Denis & Schff.) eye-spotted bud moth 1 Oedemopsis scabricula Gravenhorst (Ichneumonidae: Tryphoninae) Host Species Number Records Choristoneura rosaceana (Harris) oblique-banded leafroller 5 Pandemis sp. (prob. heparana) 1 Oncophanes americanus (Weed) (Braconidae: Hormiinae) Host Species Number Records Archips fuscocupreanus Wlsm. apple tortrix 1 Archips rosanus (L.) European leafroller 1 Ogilus punctator (Nees) (Braconidae: Orgilinae) Host Species Number Records Coleophora serratella (L.) cigar case-bearer 3 Pimpla hesperus Townes (Ichneumonidae: Pimplinae) Host Species Number Records Enarmonia formosana (Scopoli) cherry bark tortrix 4 Scambus hirticauda Provancher (Ichneumonidae: Pimplinae) Host Species Number Records Choristoneura rosaceana (Harris) oblique-banded leafroller 3 Triclistus emarginalus Say (Ichneumonidae: Metopiinae) Host Species Number Records Choreutis pariana Clerck apple and thorn skeletonizer 17

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This project was a cooperative effort of the Washington State Department of Agriculture and the USDA Animal and Plant Health Inspection Service (APHIS). Funding for field and lab support staff were provided by a Cooperative Agricultural Pest Survey (CAPS) grant from the USDA APHIS Western Region (#99-8553-0249-CA). 1 Eric LaGasa, Chief Entomologist, Pest Program / Plant Protection Division, Washington State Department of Agriculture, P.O. Box 42560, Olympia, Washington 98504-2560, (360) 902-2063 PestProgram@agr.wa.gov 2 Research Entomologist - Washington State University, Vancouver Research and Extension Center, Vancouver, WA 98665-9752 3 Entomology Technicians (Project Positions) - Washington State Department of Agriculture, Olympia, Washington 98504-2560 This report is provided as a public resource for the detection and identification of insect pests described. This entire report, as well as individual graphic images, may be freely copied, distributed, and used in electronic and printed format as long as they are not modified for content or used for commercial purposes.