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 rosacea na (Harris), collected from commercial raspberry fields in the Fraser Valle y, British Columbia, Canada, over 3 years. Levels of parasitism ranged from 5 to 15%. Among these 14 species, five represent new host records. A polye mbryonic 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 unisexu al or mixed-gender groups. Overall male to female sex ratio was 1:4. Head c apsules of mature parasitized host larvae were significantly larger than th ose of unparasitized ones, suggesting that C. rosaceana larvae parasitized by M. nigridorsis might have an extra larval stage.