Dynamics of carbendazim-resistant frequency of pathogen associated with the epidemic of Fusarium head blight.

Carbendazim resistance was detected using 4701 Fusarium graminearum species complex (FGSC) isolates collected from major wheat producing regions in China from 2018 to 2020. A total of 348 carbendazim-resistant isolates were identified. The majority of carbendazim-resistant isolates were detected in Jiangsu and Anhui Provinces. 227 and 88 isolates were obtained from each of Jiangsu and Anhui Provinces with the high resistance frequency of 41.12% and 20.56%. The predominant resistant isolates harboring point mutation F167Y (79.31%), followed by E198Q (16.38%) and F200Y (4.31%). Compared with F. graminearum, F. asiaticum isolates were more likely to produce carbendazim resistance. In this study, we firstly detected carbendazim-resistant isolates in Hebei, Shaanxi, Sichuan and Hunan Province. In Jiangsu, Anhui and Zhejiang, the frequency of carbendazim-resistant isolates maintained a high level resulting in stable carbendazim-resistant populations. We also found the dynamic of carbendazim-resistant frequency in most provinces showed similar trend of the epidemic of FHB. Our results facilitate the understanding of the current situation of carbendazim resistance of FHB pathogens, and will be helpful for fungicides selection in different wheat producing areas in China.