Genetic mutations and insecticide resistance in Diaphorina citri: a comparative study across Chinese citrus regions

BACKGROUND Diaphorina citri , a serious pest of citrus, causes significant economic losses due to its role in spreading Huanglongbing. Chemical treatment is the primary method for controlling D. citri . In recent years, D. citri has demonstrated varying resistance levels to a number of pesticides. Combination bioassay and amplicon sequencing approaches can provide a more accurate assessment of resistance in D. citri . RESULTS Field populations of D. citri exhibited significant variability in pesticide susceptibility depending on geographic location. The Guilin population showed the highest imidacloprid sensitivity, with a median lethal concentration (LC 50 ) of 1.14 mg L −1 , indicating a comparatively high susceptibility to this pesticide. In contrast, the Chongzuo population exhibited the lowest sensitivity, with an LC 50 exceeding 2000 mg L −1 , reflecting a significant resistance level. Molecular analysis showed that resistance levels were associated with specific genetic mutations in two key areas: VGSC_L925M, VGSC_M918T, and the acetylcholine receptor α (nAChRα_N88S). Furthermore, there was a correlation between the rate of these mutations and the resistance level. Interestingly, the VGSC_L925M mutation was prevalent in the Chongzuo population, exhibiting a significant frequency of 42.08%. The nAChRα_N88S mutation, found at a low frequency of 0.24%, was unique to the Chongzuo population. CONCLUSION The frequency of VGSC_L925M mutations linked to pyrethroid resistance and nAChRα_N88S mutations associated with neonicotinoid resistance has been revealed in D. citri from major citrus-producing regions in China. We recommend region-specific resistance management strategies, immediate reduction of pyrethroid use in Chongzuo area with high L925M mutation frequencies. This research also provides fundamental data to manage resistance in D. citri . © 2025 Society of Chemical Industry.