田间烟草赤星病菌繁殖代数与其对杀菌剂敏感性的关系

为合理用药、提高防效,探讨了田间烟草赤星病菌繁殖代数与其对杀菌剂敏感性的关系。室内进行了在田间烟草不同生长时期采集的6个赤星病菌株对杀菌剂敏感性测定,并用聚类分析方法比较了各菌株对杀菌剂敏感性差异。结果表明,不同时期采集的不同繁殖代数烟草赤星病菌株对"菌核净"的敏感性差异显著,其中4号菌株对"菌核净"最不敏感,EC50为193 3644mg/L,已产生一定的抗药性,其次为1号菌株,EC50为102 3738mg/L,对"菌核净"最敏感的是2号和3号菌株,EC50分别为42 0390和58 4109mg/L。表明不论前期还是后期采集的菌株都有对"菌核净"敏感和不敏感的,烟草赤星病菌株的繁殖代数与其对"菌核净"的敏感性无一定规律性。从聚类分析树状图也可以看出这种敏感性的差异情况。

Relationship between Number of Reproductive Generation of Alternaria alternata in Field and its Sensitivity to Fungicide

In order to study the relationship between the number of reproductive generation of Alternaria alternata in field and its sensitivity to fungicide, the sensitivity of six isolates of Alternaria alternata from different tobacco growth stages to fungicides were determined indoors, and the sensitivity differences between the isolates were analyzed with cluster analysis method. The results showed that the isolate's sensitivity to Dimethachlon was significantly different, the EC_(50) of isolates No.4, 1, 2 and 3 was 193.3644, 102.3738, 42.0390 and 58.4109mg/L, respectively. No.4 had the least sensitivity. From these data, no obvious relationship was found between the number of isolate's generation and its sensitivity to Dimethachlon. There were both sensitive and insensitive isolates in different tobacco growth stages. The difference of sensitivities to fungicides could be viewed from the dendrogram of cluster analysis also.