Insecticide resistance and resistance mechanisms in the melon aphid, Aphis gossypii, in Shandong, China

The melon aphid, Aphis gossypii, is an important pest of vegetables. Insecticide resistance in A. gossypii has increased due to the frequent use of insecticides. We studied the levels and mechanisms of A. gossypii resistance to imidacloprid, acetamiprid and lambda-cyhalothrin here. The resistance levels of the three insecticides in 20 populations of A. gossypii varied. When compared to the susceptible strain (Lab-SS), there were two moderate resistance (MR) populations and nine low resistance (LR) populations to imidacloprid, respectively, two MR populations and two LR populations to acetamiprid, respectively, and, five MR populations and two LR populations to lambda-cyhalothrin, respectively. Gene mutation detection in the MR level populations showed arginine to threonine substitution (R81T) in three populations and lysine to glutamine substitution (K264E) in the nicotinic acetylcholine receptor (nAChR) beta 1 subunit in one population, respectively. No valine to isoleucine substitution (V62I) was found in the nAChR beta 1 subunit in any of the tested populations. The leucine to phenylalanine substitution (L1014F) in sodium channel alpha subunit was found in five MR populations. The relative expression of the CYP6CY13 gene was significantly upregulated in the Daiyue and Shenxian populations. The CYP6CY14 gene was significantly upregulated in Daiyue, Dongchangfu, Shenxian, Mengyin and Anqiu populations. The CYP6CY19 gene was significantly upregulated in the Dongchangfu and Mengyin populations. The relative expressions of the esterase E4 or FE4 genes were significantly upregulated in most of the MR populations. These results provide insight into the current insecticide resistance of A. gossypii and may contribute to more effective resistance management strategies.

Automated summary

Levels of resistance to imidacloprid, acetamiprid, and lambda-cyhalothrin varied among 20 populations of melon aphids. Mutations in the nicotinic acetylcholine receptor gene were detected in some populations with moderate resistance. Upregulation of certain detoxification enzyme genes was observed in multiple resistant populations. These findings provide valuable insights for developing more effective resistance management strategies for A. gossypii.