DEVELOPMENT RATES OF TRICHOGRAMMA MINUTUM (HYMENOPTERA: TRICHOGRAMMATIDAE) AND IMPLICATIONS FOR TIMING AUGMENTATIVE RELEASES FOR SUPPRESSION OF EGG POPULATIONS OF CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

Abstract

AbstractDevelopment rates of the parasitoid, Trichogramma minutum Riley, were studied to provide information required in timing field releases of T. minutum for suppression of egg populations of the spruce budworm, Choristoneura fumiferana (Clemens). Development was observed in eggs of 2 host species, C. fumiferana and Sitotroga cerealella (Olivier), at constant temperatures of 14, 21, and 27 °C. Parasitoid development varied directly with temperature. Parasitoids developed more rapidly in eggs of S. cerealella than in those of C. fumiferana. Parasitoid males developed faster than females in some host-temperature treatments. Development of T. minutum is apparently rapid enough to allow progeny of parasitoids released early in the spruce budworm's oviposition period to mature and be available to oviposit in budworm eggs deposited later in the budworm oviposition period. Potential release strategies are discussed.