Screening of insecticides against egg parasitoid Trichogramma brasiliensis Ashmead (Hymenoptera: Trichogrammatidae)

The cotton bollworms become serious pests and attain resistance to broad-spectrum insecticides. Trichogramma brasiliensis, an egg parasitoid could be used for control of these in their egg stages. A study was conducted to select pesticides that are less inimical to T. brasiliensis, for incorporation into integrated pest management (IPM). Adult parasitoids were exposed to glass vials treated with recommended doses of thirteen pesticides including biopesticides. Against adults seven insecticides were extremely toxic while four were slightly toxic and two chemicals were harmless. At pupal stage abamectin and imidaclorprid were slightly toxic with > 50 per cent emergence but extremely toxic to emerged adults after 24 hours i,e. < 10 per cent survival. Endosulfan, monocrotophos and cypermethrin were slightly toxic for adult and pupa with maximum survival in cypermethrin. Dimethoate showed slight toxicity to adult but extremely toxic to pupa.