Biochemical mechanisms of organophosphate and pyrethroid resistance in red hairy caterpillar Amsacta albistriga (Lepidoptera: Arctiidae)

The red hairy caterpillar, Amsacta albistriga Walker, is an important pest of groundnut, castor and cotton in India. We determined the susceptibility of Amsacta albistriga to organophosphate and synthetic pyrethroid insecticides under laboratory conditions. Biochemical profile of esterase, acetylcholinesterase, glutathione S-transferase, and glutathione S-dehydrogenase was assessed. Synthetic pyrethroid (8.82 ppm) was highly toxic as compared to organophosphate insecticide (11.5 ppm): high esterase and acetylcholinesterase activity was observed in temephos treatment. GST activity was significantly higher in λ-cyhalothrin treatment. Esterase isozyme profiling using native PAGE shows inhibition of esterase bands in λ-cyhalothrin treatment, while three distinct bands (43, 66 and 70 kDa) were observed in temephos and dichlorvos treatment. The results of the present study suggest that esterase and AChE are dominant organophosphate detoxification enzymes in Amsacta albistriga.