Fritillaria thunbergii is a valuable medicinal plant threatened by black spot disease caused by Alternaria alternata for which application of fungicides is the primary strategy. However, the detection and characterization of fungicide resistance status in F. thunbergii has not yet been reported. A total of 106 and 128 single spore isolates of A. alternata were recovered in 2015 and 2021, respectively, from 52 and 56 F. thunbergii fields located in Jinhua, Wenzhou, Hangzhou, and Ningbo, where 90% of F. thunbergii is produced. In 2015, moderate resistance to procymidone (Pro