Resistance to pydiflumetofen in Botrytis cinerea : risk assessment and detection of point mutations in sdh genes that confer resistance

Gray mold caused by Botrytis cinerea Pers. is one of the most significant airborne diseases. It can infest a wide range of crops, causing significant losses in yield and quality worldwide. Pydiflumetofen, a new generation succinate dehydrogenase inhibitor (SDHI), is currently being registered in China to control gray mold in a variety of crops. The baseline sensitivity, resistance risk, and resistance mechanism of Botrytis cinerea to pydiflumetofen were assessed in this study.A total of 138 strains of B. cinerea from 10 different regions were tested for their sensitivity to pydiflumetofen, and the mean ECThe fitness was significantly higher for all pydiflumetofen-resistant mutants than the corresponding parental. Two types of point mutations, sdhB-P225L and sdhC-G85A and I93V, might confer resistance to pydiflumetofen in B. cinerea. A precautionary resistance management strategy should be implemented. © 2021 Society of Chemical Industry.