Quantifying Imidacloprid Susceptibility in Alabama Populations of Aphis gossypii

Aphis gossypii Glover is a highly polyphagous pest that causes economic losses to many crops worldwide. Evolution of resistance to insecticides is a major concern when managing populations of A. gossypii, and resistance has been reported in numerous studies. In the southeastern U.S., few effective insecticides have historically been available for management of A. gossypii, and a reduction in efficacy of imidacloprid, one of the most widely used active ingredients, has been observed by stakeholders in Alabama. The objectives of this project were to: 1) conduct concentration-mortality bioassays to quantify the susceptibility of A. gossypii populations to imidacloprid in 2019-2020; and 2) examine relationships between imidacloprid susceptibility and cotton production intensity. The results from this study confirmed imidacloprid resistance in A. gossypii populations across Alabama. Results from objectives 1 and 2 will be presented, and implications for IPM and IRM will be discussed.