Behavioral and Physiological Effects of Neem (Azadirachta indica) Seed Kernel Extracts on Larval Parasitoid, Bracon hebetor

An aqueous suspension and an ethanolic extract of neem seed kernel (NSK) at 0.3, 0.6, 1.2, 2.5, and 5.0% concentrations were tested for ovipositional deterrency, feeding deterrency, toxicity, sterility, and insect growth regulatory effects on a larval parasitoid, Bracon hebetor. Neither NSK extracts delivered in the food or by contact influenced the B. hebetor oviposition (parasitization). They also did not cause parasitoid sterility through feeding, but they showed feeding deterrent effects for a limited period. Parasitoid eggs and pupae also were unaffected by the extracts tested. The parasitoid larvae, however, were killed by feeding contaminated host larvae and also through contact with neem extracts. Thus, a minimum safety period is suggested for inundative releases of B. hebetor in integrated pest management.