PARASITOIDS REARED FROM THE OBLIQUEBANDED LEAFROLLER (LEPIDOPTERA: TORTRICIDAE) INFESTING RASPBERRIES

Fourteen species of parasitoids (13 hymenopterans, 1 dipteran) were reared from larvae or pupae of the obliquebanded leafroller, Choristoneura rosaceana (Harris), collected from commercial raspberry fields in the Fraser Valley, British Columbia, Canada, over 3 years. Levels of parasitism ranged from 5 to 15%. Among these 14 species, five represent new host records. A polyembryonic wasp, Macrocentrus nigridorsis Viereck (Hymenoptera: Braconidae), was the most abundant parasitoid. External feeding on the final host instar is obligatory for M . nigridorsis to complete development. On average, each parasitized host larva produced about 36 M . nigridorsis , in either unisexual or mixed-gender groups. Overall male to female sex ratio was 1:4. Head capsules of mature parasitized host larvae were significantly larger than those of unparasitized ones, suggesting that C . rosaceana larvae parasitized by M . nigridorsis might have an extra larval stage.