Neonicotinoid resistance in Aphis gossypii Glover (Aphididae: Hemiptera) from Australian cotton

Abstract Cotton or melon aphid, Aphis gossypii Glover, is an important pest of cotton, and recently the neonicotinoid group of insecticides has provided a key option for control where they are used as seed treatments and foliar sprays. Here we document for the first time in Australian cotton, resistance to three neonicotinoids (acetamiprid, clothianidin and thiamethoxam) in A. gossypii via diagnostic discriminating concentration assays that were also associated with field control failure. Subsequent full log dose probit analysis on strains with discriminating dose survivors confirmed acetamiprid, clothianidin and thiamethoxam resistance at 6.4‐, 10‐ and 22‐fold, respectively. Further laboratory pressuring of strains caused acetamiprid resistance to significantly increase to 22‐fold but resistance factors to clothianidin and thiamethoxam were unchanged. Clearly there is a need to reduce overall neonicotinoid selection to prevent or slow any increase in neonicotinoid resistance. An effective method to contain resistance would be to move away from the more persistent neonicotinoid seed dressings to either organophosphate or carbamate‐based products and to limit the use of neonicotinoid foliar sprays.