中国2种橡胶树炭疽病菌对咪鲜胺敏感性比较

Comparison of Sensitivity Between Two Colletotrichum Species from Hevea brasiliensis to Prochloraz in China

炭疽病是橡胶树上一种重要的叶部病害,主要病原有胶孢炭疽菌和尖孢炭疽菌。为了解中国各植胶区炭疽菌对咪鲜胺的敏感性,采用生长速率法室内测定来自海南、云南、广东和广西4省(区)22株橡胶树胶孢炭疽病菌和15株尖孢炭疽菌对咪鲜胺的敏感性。结果表明:供试的37株橡胶炭疽病菌菌株对咪鲜胺的EC_(50)值为0.022 0~0.272 1 mg/L,平均为(0.061 7±0.055 4)mg/L,EC_(50)最大值是最小值的12.5倍。其中89.2%参试菌株的EC_(50)值介于0~0.100 0 mg/L。根据成组t检验分析结果表明,目前中国4个植胶区的2种橡胶炭疽病菌对咪鲜胺敏感性无明显差异。除了来自海南和云南地区的尖孢炭疽菌有显著性差异外,其他来自不同省份的胶孢炭疽菌和尖孢炭疽菌对咪鲜胺敏感性均无明显差异。研究显示中国橡胶炭疽菌对咪鲜胺仍具有较高的敏感性,但菌株间敏感性有一定的差异,存在一定的潜在抗性风险。

Colletotrichum gloeosporioides and C. acutatum have been reported as the main pathogens of the rubber anthracnose, which is one of the main leaf diseases of rubber tree in China. Twenty-two isolates of C. gloeosporioides and 15 isolates of C. acutatum were isolated from diseased Hevea brasiliensis collected from 4 different provinces in China. The sensitivity of these isolates to prochloraz was determined by the mycelium growth rate method. The results indicated that the ECso values of the 37 isolates ranged from 0.022 0 to 0.272 1 mg/L, with an average value of （0.061 7＋0.055 4）rag/L, and the maximum ECso value was 12.5 times as much as the minimum. Among them, the ECso value of 33 isolates （89.2%） was from 0to 0.100 0 mg/L. There were no significant difference between the average ECso value of C. gloesporioides and C. acutatum to prochloraz in total. Except for the difference observed in the C. acutatum isolates between Hainan and Yunnan, there were no significant difference between the average ECso values of the isolates from different provinces. The results indicated high sensitivity of the two Colletotrichum species to prochloraz in China, however, the potential prochloraz-resistant risk should be paid attention due to considerable variation in sensitivity to prochloraz among the isolates of Colletotrichum spp. from Hevea brasiliensis.