Dynamic Monitoring of Chilo suppressalis Resistance to Insecticides and the Potential Influencing Factors.

Chilo suppressalis is one of the most important rice pests worldwide, and chlorantraniliprole, abamectin, and methoxyfenozide have been widely used to control this pest in China. However, the control efficiency in the field has dramatically decreased in recent years. Therefore, assessing the impacts of different factors on C. suppressalis resistance is essential for maintaining control effectiveness and managing resistant populations. Herein, we investigated insecticide resistance and its potential influencing factors (biotic and abiotic factors) in C. suppressalis field populations, using bioassays and biochemical and molecular diagnostic approaches. The results showed that the resistance levels of most field populations of C. suppressalis have evolved to moderate-to-high levels to the tested insecticides. The toxicity correlation analysis indicated that there was a significant positive correlation between the resistance levels of abamectin and methoxyfenozide, whereas GST activity was positively correlated with abamectin and methoxyfenozide resistance in C. suppressalis. EST and P450 activities showed significantly positive correlation with the resistance of chlorantraniliprole and methoxyfenozide, while the increase in temperature enhanced EST enzyme activity and was positively correlated with the evolution of resistance to methoxyfenozide. Overall, our study provides a systematic understanding of the dynamic resistance status and its influencing factors of C. suppressalis to insecticides. These findings will help clarify the resistance levels and the influencing factors in the resistance development of C. suppressalis, providing a theoretical basis for the resistance management of this insect species.