The invention discloses a method for detecting the 
drug resistance of 
Corynespora cassiicoa to SDHI fungicides by using MAS-PCR technology and a used primer composition. 
Specific primers D95E-R, H105R-R, and G109V-R in the primer composition are reverse primers designed targeted to 
mutation sites D95E, H105R and G109V of 
succinate dehydrogenase D 
subunit of 
Corynespora cassiicoa resistant to boscalid correspondingly, corresponding sequences are at the 
mutation sites, and a 3'end base is specially designed, so that the specificity of the primers is improved. The method for detecting or auxiliary detecting the 
drug resistance of 
Corynespora cassiicoa to the SDHI fungicides can simultaneously detect the three 
mutation types of D95E, H105R and G109V in a PCR 
reaction tube, compared with otherdetection methods that can only detect a 
single mutation, the method has the advantages of time-saving, labor-saving, fast and high-
throughput, and a large number of samples can be accurately detected.