ORTHOSIA-HIBISCI GUENEE (LEPIDOPTERA, NOCTUIDAE) - INDIGENOUS PARASITOIDS AND THE IMPACT OF EARINUS-LIMITARUS (SAY) (HYMENOPTERA, ICHNEUMOMDAE) ON ITS HOST FEEDING-ACTIVITY

A 3-year survey of apple and cherry orchards in the interior of Britis h Columbia revealed that speckled green fruitworm, Orthosia hibisci, i s the dominant fruitworm species in the south of the Okanagan Valley. Larvae of speckled green fruitworm collected from orchards that used n o or minimal insecticides experienced 22.5-29.0% parasitism in 1988-19 90. Earinus limitarus was responsible for 98.9% of the parasitism in t he 3 years. Parasitoids of minor significance included a Meteorus sp. (Hymenoptera: Braconidae) and Compsilara concinnata (Mg.) (Diptera: Ta chinidae). Data from laboratory trials indicated that feeding by O. hi bisci in the fifth and sixth instars was significantly (P < 0.05) redu ced when larvae were parasitized by E. limitarus; Orthosia hibisci in the second through sixth instars in sleeve cages damaged developing ap ples in the field. Earinus limitarus appears able to reduce O. hibisci numbers for the following year as well as immediate host feeding dama ge in at least the last two instars.