PARASITOID COMPLEX OF ZEIRAPHERA CANADENSIS (LEPIDOPTERA: TORTRICIDAE) AND EVALUATION OF TYCHERUS OSCULATOR (HYMENOPTERA: ICHNEUMONIDAE) AS A BIOLOGICAL CONTROL AGENT

Abstract

AbstractA survey of larval and pupal populations of the spruce bud moth, Zeiraphera canadensis Mutuura and Freeman (Lepidoptera: Tortricidae), conducted from 1994 to 1996 in eastern Newfoundland, disclosed that the incidence of endemic parasitism by Hymenoptera was up to 50% for Tycherus osculator (Thünberg) (Ichneumonidae), up to 15% for Earinus zeirapherae (Walley), under 3% for Ascogaster (Wesmael 1835) sp. and Clinocentrus (Haliday 1833) sp. (Braconidae), and under 1% for Lamachus (Foerster 1868) sp. and Triclistus (Foerster 1868) sp. (Ichneumonidae). Tycherus osculator, E. zeirapherae, Ascogaster sp., and Clinocentrus sp. represent new distributional range extensions to Newfoundland, and to the nearctic region in the case of T. osculator. The biology of European populations of T. osculator was studied on a natural host, Zeiraphera diniana (Guenée). Only females overwintered and ovarian maturation did not occur until after several months of exposure to near-freezing temperatures. Tycherus osculator successfully parasitized prepupae and pupae of Z. diniana of all ages but, in the laboratory, appeared to prefer pupae. Host feeding by T. osculator was common but not necessary for ovarian maturation. Tycherus osculator imported from Europe attacked and successfully developed within the spruce bud moth host in laboratory screenings. Morphological comparisons indicated that T. osculator reared from Z. canadensis were smaller than those reared from Z. diniana. Tycherus osculator obtained from either Newfoundland or Europe may have potential as a biological control of Z. canadensis in mainland Canada, where it is presently absent.