Comparative study on the susceptibility of macropteous and brachypterous Nilaparvata lugens to insecticides

The susceptibility to twelve commonly used insecticides and detoxification enzyme activity of wing dimorphic Nilaparvata lugens were compared. The rice seedling dipping method was used for the bioassay of nitenpyram, cycloxaprid, dinotefuran, thiamethoxam, clothianidin, imidacloprid, chlorpyrifos, dichlorvos, buprofezin, isoprocarb, pymetrozine and etofenprox. The results showed that macropterous N. lugens was more susceptible to the neonicotinoid insecticides including dinotefuran, thiamethoxam, clothianidin and imidacloprid than that of the brachypterous speices. On the contrary, brachypterous N. lugens was more susceptible to the organophosphorus insecticide chlorpyrifos than the macropterous speices. While no significant difference in the susceptibility to nitenpyram, cycloxaprid, dichlorvos, buprofezin, isoprocarb, pymetrozine and etofenprox was observed between those two biotypes of N. lugens. The results of relative specific activity of the detoxification enzyme assay showed that the specific activity of esterase of macropteous N. lugens was significantly higher than that of the brachypteous speices, while the cytochrome P450 monooxygenase specific activity was significantly lower than that of brachypteous speices. The specific activity of glutathione S-transferase showed no significant difference. These results will be helpful for the chemical controlof the wing dimorphic N. lugens.