Effect of Insecticides on Some Biological Parameters of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammtidae)

Abstract

Bioassay carried out to determine the toxicity of seven insecticides (viz. endosulfan 0.07%, imidacloprid 0.004%, spinosad 0.01%, triazophos 0.08%, thiodicarb 0.075%, novaluron 0.01% and azadirachtin @1ml/L) to Trichogramma chilonis showed that spinosad was the most toxic in all the studies followed by triazophos. Spinosad resulted in only 17.80 per cent parasitization and 3.97 per cent adult emergence from the host eggs, Corcyra cephalonica Stainton treated before parasitization. Novaluron was found to be the safest resulting in 58.93 per cent parasitization and 89.72 per cent adult emergence from the host eggs treated before parasitization. The parasitization in other insecticides ranged from 20.00 to 40.47 per cent. Spinosad was also found highly toxic to all the immature stages of T. chilonis resulting in only 0.46, 0.66 and 0.65 per cent adult emergence when the parasitoid was treated in the egg, larval and pupal stages, respectively. Novaluron was found to be safe to all the immature stages of the parasitoid resulting in 86.75, 87.84 and 87.46 per cent adult emergence when treated in egg, larval and pupal stages, respectively. The parasitoid adult emergence in other insecticides ranged from 57.95 to 88.63 per cent when treated in egg stage, 53.97 to 87.12 per cent when treated in larval stage and 61.46 to 87.15 per cent when treated in pupal stage.