Identification and fungicide resistance of anthracnose pathogen in Cunninghamia lanceolata in Hunan Province

To clarify the pathogen species and fungicide resistance characteristics of Chinese fir anthracnose in Hunan Province, China, this study collected samples from four regions （Huaihua, Xiangtan, Chenzhou, and Youxian County of Zhuzhou） in Hunan, obtaining 124 Colletotrichum isolates. Through phylogenetic analysis of the ApMat gene sequence combined with morphological characteristics, all strains were identified as Colletotrichum cangyuanense Z.F. Yu. The resistance of these isolates to four fungicides （carbendazim, diethofencarb, tebuconazole, and prochloraz） was evaluated using discriminatory dose assays. The results demonstrated that 28 isolates （22.6%） exhibited resistance to carbendazim, while 26 isolates （20.9%） showed resistance to tebuconazole, including 4 isolates （3.2%） displaying dual resistance to both fungicides. Sequence analysis of the β-tubulin gene revealed no mutations in all 28 carbendazim-resistant isolates. This study confirms the emergence of resistance to carbendazim and tebuconazole in C. cangyuanense populations infecting Chinese fir in Hunan, while no prochloraz resistance was detected, providing critical evidence for developing control strategies.