Abstract:  【Aim】 To determine the resistance level of Chilo suppressalis collected from Anhui Province to diamide insecticides and to investigate the differentially expressed genes in response to tetraniliprole and chlorantraniliprole, so as to provide a theoretical basis for rational use of insecticides and resistance management of C. suppressalis. 【Methods】 The resistance levels of the 3rd instar larvae of four field populations of C. suppressalis from Nanling, Dongzhi, Lujiang and Wangjiang of Anhui Province collected in March to July, 2023 and a laboratory susceptible population (CS) of C. suppressalis to chlorantraniliprole, cyantraniliprole and tetraniliprole were tested by rice stem dipping method. PCR was used to analyze the mutation frequency of Y4667D, Y4667C, I4758M, Y4891F and G4915E in the ryanodine receptor (RyR) gene associated with the resistance to diamide insecticides among the populations of C. suppressalis from Lujiang, Dongzhi, Dangtu, Nanling, Wuwei, Susong, Wangjiang, Huoqiu and Fengtai, and the CS population of C. suppressalis. The transcriptome sequencing was performed to investigate the differentially expressed genes that may be involved in the response of C. suppressalis to chlorantraniliprole and tetraniliprole in the 3rd instar larvae of the CS population after exposure to the median lethal concentration (LC₅₀) of chlorantraniliprole and tetraniliprole. GO function annotation and KEGG pathway enrichment analysis were performed for the differentially expressed genes. 【Results】 The four field populations of C. suppressalis from Nanling, Dongzhi, Lujiang and Wangjiang had different degrees of resistance to chlorantraniliprole, cyantraniliprole and tetraniliprole, respectively. Among them, the Wangjiang population had the highest level of resistance to the three insecticides, with the resistance ratios of 253.8, 38.4 and 112.2-fold, respectively. The mutation frequencies of I4758M, Y4667D, Y4891F and Y4667C associated with the resistance to diamide insecticides in the seven C. suppressalis populations in Anhui Province were 52.8%, 32.3%, 4.7% and 0.9%, respectively, however, the mutation of G4915E was not detected. Meanwhile, no mutation was detected in the Huoqiu, Fengtai and CS populations.  The expression levels of 2 547 differentially expressed genes in the 3rd instar larvae of the CS population after exposure to LC50 of chlorantraniliprole and tetraniliprole were obviously changed as compared with those in the control group. Among the 2 547 differentially expressed genes, 2 531 differentially expressed genes had the same response patterns to the two insecticides, while only 16 differentially expressed genes had the opposite response patterns to the two insecticides. Differentially expressed genes in response to chlorantraniliprole and tetraniliprole were enriched in localization, cellular processe, cell, macromolecular complex, binding, catalytic activity, metabolism, genetic information processing and organismal systems. 【Conclusion】 The regional control measures of C. suppressalis should be implemented in Anhui Province as soon as possible. The diamide insecticides should be rationally used in the sensitive areas to delay the development of resistance. In resistant areas, comprehensive measures should be taken to control the resistance, and restore the high efficiency of diamide insecticides to improve the control efficacy.

Key words: Chilo suppressalis, diamide insecticides, resistance monitoring, ryanodine receptor, transcriptome