Insecticide Resistance Monitoring in Field Populations of the Whitebacked Planthopper Sogatella furcifera (Horvath) in China, 2019–2020

SIMPLE SUMMARY: The whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), is one of the most destructive pests that seriously threatens the high-quality and safe production of rice. Overuse of chemical insecticides has led to varying levels of resistance to insecticides in the field population of S. furcifera. In this study, we measured the susceptibility of 18 populations to 10 insecticides by the rice-seedling dip method. Enzyme assays were performed to measure the levels of esterase (EST), glutathione S- transferase (GST) and cytochrome P450 monooxygenase (P450). A risk of cross-resistance between some insecticides were found by pairwise correlation, and EST may be contributed to the resistance to nitenpyram, thiamethoxam and clothianidin in S. furcifera. Overall, our findings will help inform the effective insecticide resistance management strategies to delay the development of insecticide resistance in S. furcifera. ABSTRACT: Monitoring is an important component of insecticide resistance management. In this study, resistance monitoring was conducted on 18 field populations in China. The results showed that S. furcifera developed high levels of resistance to chlorpyrifos and buprofezin, and S. furcifera showed low to moderate levels of resistance to imidacloprid, thiamethoxam, dinotefuran, clothianidin, sulfoxaflor, isoprocarb and ethofenprox. Sogatella furcifera remained susceptible or low levels of resistance to nitenpyram. LC(50) values of nitenpyram and dinotefuran, imidacloprid, thiamethoxam, clothianidin and chlorpyrifos exhibited significant correlations, as did those between dinotefuran and thiamethoxam, clothianidin, sulfoxaflor, imidacloprid, isoprocarb and buprofezin. Similarly, significant correlations were observed between thiamethoxam and clothianidin, sulfoxaflor and imidacloprid. In addition, the activity of EST in field populations of S. furcifera were significantly correlated with the LC(50) values of nitenpyram, thiamethoxam and clothianidin. These results will help inform effective insecticide resistance management strategies to delay the development of insecticide resistance in S. furcifera.