Safety of insecticides against Aenasius bambawalei hayat (Hymenoptera: Encyrtidae)

Six insecticides viz; chlorpyriphos 20 EC (0.1%), endosulfan 35 EC (0.14%), monocrotophos 36 SL (0.08%), malathion 50 EC (0.25%), dichlorvos 76 EC (0.3%), and alphamethrin 10 EC (0.02%) were evaluated for their toxicity against Aenasius bambawalei the solitary endoparasitoid of mealybug, Phenacoccus solenopsis. At the recommended field dose their residual toxicity was extremely high, registering 100% mortality at 24 hrs of exposure. However, when dose was reduced by twenty times the contact toxicity of alphamethrin (55.23%) followed by monocrotophos (78.57%) was less. It was noticed that endosulfan as contact poison was more toxic (85.23%) than as stomach poison (10.88%) and unlike alphamethrin; which showed 55.23% mortality as contact poison while 65.30% as stomach poison. The only insecticide, which did not record mortality after 1 hr exposure, was alphamethrin.