水稻纹枯病菌对几种常用杀菌剂的敏感性分析

Sensitivity analysis of the pathogen of rice sheath blight to several common fungicides

为明确水稻纹枯病菌对生产上常用药剂的敏感性,从江苏省及全国其他地区共分离获得纹枯病菌株293株,采用含药培养基-区分计量法测定菌株对药剂的敏感性,确定病菌对药剂的敏感基线,检测其抗性频率。结果表明:水稻纹枯病菌对噻呋酰胺、戊唑醇和丙环唑的敏感基线分别为0.129 0、0.834 3和0.660 3μg·mL^-1,以敏感基线10倍值为标准测定各地菌株对3种药剂的抗性频率发现,除5个菌株对丙环唑产生了抗性外,绝大多数菌株对3种药剂均表现敏感。据各菌株对3种药剂的敏感性相关分析显示,水稻纹枯病菌对3种药剂不存在交互抗性。所有供试菌株对井冈霉素均表现较高抗性,近70%菌株EC50值大于500μg·mL^-1。该研究说明除井冈霉素外,其他3种药剂在田间均有很好的防病效果,但应注意其用量和使用频次。

In order to detect the sensitivity of Rhizoctonia solani,the pathogen of rice sheath blight,to several common fungicides used in the field,293 isolates were isolated from the rice plants and used to determine the sensitivity baseline and resistance frequency.Results showed that the sensitivity baselines of strains to thifluzamide,tebuconazole and propiconazole were 0.1290,0.8343 and 0.6603μg·mL^-1,respectively.When the concentrations of the fungicides,used to detect the resistance frequency of the strains,were 10 folds of the sensitivivty baselines,most of the strains were sensitive except a few strains resistant to propiconazole.However,all the strains showed resistance to validamycin and the EC50 values of nearly seventy percent of the tested strains were more than 500μg·mL^-1.There was no cross-resistance to the three fungicides in R.solani.Together,these results indicated that the three fungicides,thifluzamide,tebuconazole and propiconazole,would control effectively on rice sheath blight in the field.However,the dosages and frequencies should be controlled when the three fungicides were used in the field.