CYTOCHROME P450 MONOOXYGENASES ASSOCIATED WITH PYRETHROID RESISTANCE IN HELICOVERPA ARMIGERA (HÜBNER)

Abstract  The relationship between the cytochrome P-450 (cytP⁴⁵⁰ monooxygenase and insecticide resistance mechanisms in Helicoverpa armigera was studied. The level of cytP450 and activity of p -ni-troanisole ( p -NA) O-demethylase in resistant strain were 1. 71 times and 2. 21 times respectively higher as compared with those of the susceptible strain. Aldrin epoxidase activity showed 1. 35 fold strain difference. Therefore aldrin epoxidase might not be important for H. armigera resistance mechanism, the level of cytP450 and activity of p -NA O-demethylase might play a vital role in H. armigera resistance mechanisms. The reason of different resistance mechanisms among different H. armigera resistant strains is discussed.