Changes in susceptibility to conventional insecticides of a Cry1Ac-selected population of Helicoverpa armigera (Hubner) (Lepidoptera:Noctuidae)

摘要

The changes in the susceptibility of the cotton bollworm,Helicoverpa armigera (Hiibner) to three insecticides (lambda-cyhalothrin,phoxim and endosulfan) commonly used for control of this pest in China were monitored by bioassays at various generations.The insects were originally collected from Bt cotton fields and selected with CrylAc over 44 generations.In comparison with a susceptible strain,the larval resistance of the Bt-selected populations to CrylAc toxin increased 106-fold.Simultaneously,the resistance levels to lambda-cyhalothrin,phoxim and endosulfan declined dramatically.The results indicated no positive cross-resistance between CrylAc toxin and the insecticides.Evidence of the lack of cross-resistance to three commonly used synthetic insecticides in our laboratory-derived CrylAc-resistant population may suggest that growers can confidently use these insecticides if and when resistance to CrylAc cotton does occur.