Effect of novel insecticides to Trichogramma chilonis and Snellenius maculipennis, the potential parasitoids of castor semilooper

Abstract

Aim : The present investigation was undertaken to evaluate the toxicity of seven novel chemical and biological insecticides [flubendiamide 39.35 SC, chlorantraniliprole 18.5 SC, emamectin benzoate 5 SG, novaluron 10 EC, indoxacarb 15.8 EC and two Bacillus thuringiensis var. kurstaki (Btk) formulations] and five conventional chemical insecticides (dimethoate 30 EC, malathion 50 EC, monocrotophos 36 SL, profenofos 50 EC and lambda-cyhalothrin 5 EC) against the parasitoidsof castor semilooper. Methodology : The toxic effect of insecticides was evaluated by treating the parasitized eggs using an atomizer in the case of egg parasitoid, Trichogramma chilonis, while topical bioassay and dry film residue method was used against pupal and adult stages of larval parasitoid, Snellenius maculipennis, respectively. The effect was categorized as per International Organisation for Biological Control Safety Classification. Results : The toxicity of insecticides against T. chilonis revealed that Btk formulations, flubendiamide, chlorantraniliprole, indoxacarb and novaluron had lesser effect on adult emergence and categorized as harmless (< 30% mortality). Topical bioassay with pupae of S. maculipennis revealed that Btk formulations, novaluron, flubendiamide, chlorantraniliprole, emamectin benzoate, indoxacarb, dimethoate and profenofos were rated as harmless (< 30% mortality). Dry film residue method using adults of S. maculipennis revealed that Btk formulations, novaluron, flubendiamide and chlorantraniliprole were rated as harmless (< 30% mortality). Interpretation: Btk formulations, flubendiamide, chlorantraniliprole and novaluron were found harmless to both egg parasitoid, T. chilonis and larval parasitoid, S. maculipennis. These safer insecticides can be incorporated in IPM module to unify thesafeandsustainable use of chemical and bio-control methods.