Monitoring of Insecticide Resistance and Resistance-Related Point Mutations in Field-Collected Aphis gossypii Populations in the Northern Xinjiang, China

In 2024 and 2025, field populations of Aphis gossypii were collected from eight regions in Xinjiang to monitor their resistance levels to five commonly used insecticides: sulfoxaflor, acetamiprid, imidacloprid, abamectin, and chlorpyrifos. The mutation frequencies of five sites in the acetylcholinesterase (AChE) gene (S431F, V332A, A302S, G221A, F139L) and three sites in the β1 subunit of the nicotinic acetylcholine receptor (nAChR) (R81T, V62I, K264E) were also analyzed. The results showed that from 2024 to 2025, the eight A. gossypii field populations exhibited the highest resistance to imidacloprid (primarily moderate to high resistance), followed by acetamiprid (all moderate resistance). Resistance to abamectin and sulfoxaflor was relatively low, but sulfoxaflor resistance increased rapidly (from low resistance in 2024 to moderate resistance in 2025). All populations remained consistently susceptible to chlorpyrifos. Gene analysis revealed that the mutation rate of S431F in the AChE gene was nearly 100%, while that of V332A remained stable at approximately 30%. The mutation rates of A302S and G221A showed a slight increase, whereas the F139L mutation rate was extremely low (