中国河南省小麦纹枯病菌对苯醚甲环唑及戊唑醇的敏感性

为明确中国河南省小麦纹枯病菌对苯醚甲环唑及戊唑醇的敏感性，采用菌丝生长速率法测定了2种药剂对采自河南省15个地市分离的95株病菌的毒力。结果显示:供试菌株对苯醚甲环唑和戊唑醇的EC50值分别在0.014~1.609和0.002~0.064 μg/mL之间。敏感性频率分布图显示:在小麦纹枯病菌群体中已出现对苯醚甲环唑敏感性下降的亚群体，而对戊唑醇则不明显；可将其中呈连续单峰频次分布的大多数菌株群体的平均EC50值（0.165±0.101）和（0.019±0.008）μg/mL分别作为小麦纹枯病菌对苯醚甲环唑和戊唑醇的相对敏感基线。苯醚甲环唑的平均EC50值是戊唑醇的26倍，表明该病原菌对戊唑醇更为敏感。不同地区病原菌群体间对苯醚甲环唑和戊唑醇的敏感性均存在显著性差异。小麦纹枯病菌对2种杀菌剂的敏感性之间存在着微弱的正相关性。本研究结果可为河南省小麦纹枯病防控杀菌剂的合理使用提供理论依据。

Sensitivity to difenoconazole and tebuconazole of Rhizoctonia cerealis in Henan province in China

The sensitivities ofRhizoctonia cerealisto difenoconazole and tebuconazole were evaluated by measuring the mycelial growth on the fungicide-amended media using 95 isolates collected from 15 cities within Henan province, China. The results indicated that 50% effective concentration (EC50) values of all isolates to difenoconazole and tebuconazole ranged from 0.014 to 1.609 μg/mL and 0.002 to 0.064 μg/mL, respectively. The results of the frequency analysis revealed that subpopulation, which is less sensitive to difenoconazole had been discovered in the tested isolates. However, most of isolates were sensitive to tebuconazole. The mean EC50values of (0.165 ± 0.101) μg/mL and (0.019 ± 0.008)μg/mL for most isolates showed a unimodal curve distribution, which was treated as the sensitivity baseline ofR. cerealisto difenoconazole and tebuconazole respectively. The mean EC50value of difenoconazole was 26 times higher than that of tebuconazole, which meant thatR. cerealiswas more sensitive to tebuconazole. The isolates collected from different regions demonstrated different sensitivities. Especially, the correlation efficient existed between difenoconazole and tebuconazole was very low. The results provided a theoretical basis for the efficient application of fungicides in the control of wheat sharp eyespot in the field in Henan province.