Effect of Insecticides on Development and Adult Survival of Trichogramma chilonis (Trichogrammatidae: Hymenoptera)

Abstract— The effect of insecticides on development and adult survival of Trichogramma chilonis was investigated under laboratory condition. Insecticides tested were endosulfan, coragen, monocrotophos and deltamethrin+triazophos on following concentration i.e. 0.009%, 0.010%, 0.020%, 0.022% and 0.024%. Treating eggs with all the concentration of chemical insecticides caused death of the emerged adults within few hours post emergence when the treatment was carried out 4 days post parasitism or one day before adult emergence. The number of host eggs turned to black (the parasitoid larvae developed to pupae) varied according to timing of treatment. Adult emergence rate varied according to the used insecticide, the parasitoid stage and the generation. All the concentration of insecticides, with the exception of endosulfan and some cases coragen, adversely affected T. chilonis emergence from Corcyra cephalonica host eggs when exposed at 1st, 2nd, 3rd, 5th and 6th day of developmental stages (larval and pupal) of T. chilonis. Regardless of the developmental stage treated, none of the insecticides tested had a significant effect on the emergence and survival of T. chilonis male and a female significantly varied among insecticide treatments, and were significantly affected by the developmental stage of parasitoid when treated. Based on toxicity, deltamethrin+triazophos was the most toxic followed by monocrotophos, which was comparatively less toxic compounds to adult male and female T. chilonis. No parasitoids emerged from parasitized eggs treated with deltamethrin+triazophos in second generation.