Anthranilic diamide compatibility with the parasitoid Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae): based on Toxicity, Two-sex life table and ecological parameters

Abstract

Egg parasitoid wasps of genus Trichogramma Westwood are effective natural enemies of lepidopteran pests in various crops. However, the efficacy of Trichogramma parasitoids is adversely affected by insecticides applied in the field to manage these lepidopteran pests. To overcome this problem efficiently, there is an urgent need to incorporate insecticide-resistant Trichogramma strains into integrated pest management (IPM) programs. This study assessed the potential of Trichogramma chilonis Ishii to develop chlorantraniliprole resistance and characterized resistance associated fitness costs and stability. Toxicity bioassays were performed on T. chilonis using a dry film residue method. After 39 selections, a 573.64-fold level of resistance to chlorantraniliprole was developed in the resistant strain of T. chilonis (Chlr-R) when compared with a chlorantraniliprole susceptible strain (Chlr-S). Chlorantraniliprole resistance in Chlr-R resulted in a female biased sex-ratio and significantly increased the total life span and longevity of the adult female when compared to the Chlr-S strain. Based on age-stage, two-sex life table all the demographic parameters of Chlr-R increased significantly. These results indicate that T. chilonis can be mass reared and selected for chlorantraniliprole resistance under laboratory conditions, is an important step to improve the in field-based effectiveness and integration of these wasps with chemical control.