Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen with a broad host range and a worldwide distribution.Boscalid belongs to the class of succinate dehydrogenase inhibitors (SDHIs) and exhibits a broad-spectrum antifungal activity on various crops.Numerous studies have indicated that mutations in highly conserved amino acid residues located in succinate dehydrogenase (SDH) complex are responsible for SDHI resistance in various fungi and bacteria.In S.sclerotiorum,boscalid resistance has been detected in one field isolate with a mutation H134R in SDHD gene.In this study, however, a new point mutation A11V (GCA to GTA) in SDHB gene has been detected in S.sclerotiorum boscalid resistant (BR) isolates.