贵州省水稻纹枯病菌对丙环唑和吡唑醚菌酯的敏感性

Sensitivities of Rhizoctonia solani to Propiconazole and Pyraclostrobin on Rice Plants in Guizhou Province

【目的】明确贵州省水稻纹枯病菌对丙环唑和吡唑醚菌酯的敏感性,为水稻纹枯病的科学防治及合理用药提供参考。【方法】采用菌丝生长速率法测定从贵州省4个地区采集分离的52株水稻纹枯病菌对丙环唑和吡唑醚菌酯的敏感性及药剂间的相关性。【结果】供试菌株对丙环唑的EC50值为0.058~2.381μg·mL-1,均值为0.422μg·mL-1;供试菌株对吡唑醚菌酯的EC50值范围从0.077~0.936μg·mL-1,均值为0.313μg·mL-1。抗性水平分析表明,湄潭地区的水稻纹枯病菌对丙环唑和吡唑醚菌酯出现了低抗水平的菌株,抗性频率分别为16.7%、13.3%。聚类分析表明,水稻纹枯病菌对丙环唑和吡唑醚菌酯的敏感性差异与菌株地理来源无明显相关性,且这两种药剂的敏感性之间也无显著相关性。【结论】供试菌株中多数菌株对丙环唑和吡唑醚菌酯的敏感性较高。药剂间未产生交互抗性,生产上可以交替使用。

【Objective】 Sensitivities of Rhizoctonia solani on rice to propiconazole and pyraclostrobin were determined for proper pesticide application on the disease control in Guizhou.【Method】 Mycelium growth rate was used as the criterion for testing the pesticide sensitivities of 52 strains of R. solani collected from 4 regions in the province.【Result】 The EC50 of propiconazole on the pathogens ranged from 0.058 μg·mL-1 to 2.381 μg·mL-1, averaging 0.422 μg·mL-1. That of pyraclostrobin were between 0.077 μg·mL-1 and 0.936 μg·mL-1, averaging 0.313 μg·mL-1. Strains of low resistance to the pesticides were found in Meitan area of the province with a resistance frequency of 16.7% on propiconazole and 13.3% on pyraclostrobin. A cluster analysis showed no significant correlation between the pesticide sensitivities and the geographical origins of the pathogens, nor between the two pesticides.【Conclusion】 A large number of the R. solani isolates in the study were highly sensitive to propiconazole and pyraclostrobin, and no apparent cross-resistance observed between the two fungicides. Hence,alternative application of them for disease control was deemed appropriate.