山茶炭疽菌对茶树的致病性及其对杀菌剂的敏感性研究

山茶炭疽菌（Colletotrichum camelliae）是引起茶树叶部病害的优势致病菌。从中国13个产茶省的茶树病叶中分离获得65株炭疽菌菌株，基于多基因系统发育树，结合菌落和分生孢子形态特征，对分离菌株进行鉴定，结果表明，分离菌株均属于山茶炭疽菌。采用离体叶片接种的方法进行致病力测试，结果显示，所有菌株均能导致茶树叶片发病，但不同菌株间的致病力存在显著差异。YCW1180、YCW1331、YCW1382、YCW1387、YCW1419、YCW1443、YCW1451、YCW1453、YCW1454、YCW1461、YCW1613和YCW2134等12个菌株致病力显著强于其他菌株，菌株YCW1378致病力最弱。采用菌落生长速率法测试65个山茶炭疽菌菌株对25%吡唑醚菌酯的敏感性，药剂敏感性结果显示，25%吡唑醚菌酯对菌株YCW1436的菌丝生长抑制率仅为36.00%，抑菌效果最差，而对大部分菌株的抑制率高于70.00%，表明大部分菌株对该药剂高度敏感。显微镜观察结果显示，25%吡唑醚菌酯影响了山茶炭疽菌分生孢子的萌发。以上研究结果为有效防治茶树叶部病害提供了理论基础。

Pathogenicity and Fungicide Sensitivity of Colletotrichum camelliae from Tea Plant (Camellia sinensis)

Colletotrichum camelliae is the dominant species causing foliar diseases of tea plants (Camellia sinensis). In this study, 65 isolates of C. camelliae were obtained from diseased leaves of tea plants in the 13 main tea-producing provinces of China. Phylogenetic analysis based on the multigene sequences was performed on all isolates, combined with their characteristics of colony and conidia, showed that all isolates clustered with C. camelliae. Pathogenicity analysis performed on detached leaves showed that all isolates of C. camelliae could infect the tea leaves, but the virulence of the isolates displayed a significant difference. The pathogenicity of 12 isolates, including YCW1180, YCW1331, YCW1382, YCW1387, YCW1419, YCW1443, YCW1451, YCW1453, YCW1454, YCW1461, YCW1613 and YCW2134, was significantly stronger than that of other isolates. By contrast, the pathogenicity of YCW1378 isolate was the weakest. The sensitivity of 65 isolates to 25% pyraclostrobin was determined by analyzing the inhibition rate of mycelial growth. The results show that the inhibition rate of pyraclostrobin on mycelial growth of YCW1436 isolate was only 36.00%, showing the worst antimicrobial effect. However, the inhibition rate of mycelial growth of most isolates was higher than 70.00%, which suggests that most isolates were highly sensitive to 25% pyraclostrobin. Microscopic observation shows that this agent mainly affected the conidial germination of C. camelliae. Overall, this study provided a solid foundation for the effective control of the diseases.