Abstract: Boscalid is widely used in control of strawberry gray mold disease. However，it is at a high risk of resistance development for Botrytis cinerea to boscalid. The resistance was mainly caused by mutations of SdhB gene. The method of AS-PCR（Allele-specific PCR）is always used to detect point mutations in DNA. In order to evaluate the resistance mechanism to boscalid of Botrytis cinerea from strawberry in Shanghai，resistance strains in 126 isolates of 2018 were SdhB-sequenced. The results showed 4 types of mutations associated to boscalid resistance in Shanghai，P225F，N230I，H272R and H272Y. Among then，H272R and P225F were the dominant type. Therefore，for rapid detection，the tri-primer including 2 specific primers was designed and selected based on AS-PCR principle，and the PCR system was optimized to develop the method，by which the 4 types of mutations could be distinguished from the wild sensitive type in one PCR reaction.

Key words: strawberry, Botrytis cinerea, AS-PCR, boscalid, detection of fungicide resistance