Submitted to: Journal of Insect Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/2/2009
Publication Date: 7/25/2010
Citation: Pfannenstiel, R.S., Unruh, T.R., Brunner, J.F. 2010. Overwintering hosts for the exotic leafroller parasitoid, Colpoclypeus florus: Implications for habitat manipulation to augment biological control of leafrollers in pome fruits. Journal of Insect Science. 10:Article 75. Interpretive Summary: Managed and native (mostly riparian) habitats were surveyed for leafrollers in the apple producing region of central Washington State and northern Oregon during September and October of 1997-99 to identify caterpillars that supported overwintering by the parasitoid, Colpoclypeus florus. C. florus requires medium to large larva to overwinter and few leafrollers of a suitable size were discovered during the study. Five potential hosts were collected over the three years. Of these, three were confirmed as overwintering hosts for C. florus. However, only one of these, the strawberry leafroller (A. comptana), was collected at many locations in central Washington and was frequently found to be an overwintering host for C. florus. The strawberry leafroller was found feeding on two Rosaceae: Wood's rose and strawberry. This leafroller appears to be the primary overwintering host for C. florus in Washington. Introduction of strawberry leafroller populations to near-orchard habitats may facilitate biological control of leafrollers that are orchard pests.
Technical Abstract: Thirty sites of managed and native (mostly riparian) habitats were surveyed for leafrollers in the apple-producing region of central Washington State and northern Oregon during September and October of 1997, 1998, and 1999 to identify species that supported overwintering by the parasitoid Colpoclypeus florus (Walker) (Hymenoptera: Eulophidae). C. florus required medium to large larva for overwintering and few suitable leafroller species were discovered during the three years. Five potential hosts were collected including three tortricids: Ancylis comptana (Froelich), Xenotemna pallorana (Robinson) and a Syndemis sp., a gelechiid, Filatima sp., and the gracillariid Caloptilia burgessellia (Zeller). Of these, A. comptana, Syndemis sp., and Filatima sp. have been confirmed as overwintering hosts for C. florus. During this study, Syndemis sp. was rare and observed at only one location feeding on red-osier dogwood, Cornus sericea L. (Cornaceae). Filatima sp. was common in the Yakima valley feeding on cottonwood (Populus blsamifiera L.) but was rarely parasitized. A. colmptana, was collected at manyu locations in central Washington and frequently found with diapausing C. florus. A. comptana was found feeding on two Rosaceae: Wood's rose (Rosa woodsii Lindl.) and strawberry (Fragaria x ananassa Duchesne). A. comptana appears to be the primary overwintering host for C. florus in Washington. Introduction of A. comptana populations to near-orchard habitats may facilitate biological control of leafrollers.