马铃薯晚疫病菌对瑞毒霉抗性的测定

1994年秋季，在河北、黑龙江、内蒙、甘肃部分马铃薯种植区采集晚疫病病叶或病薯，共分离到66个菌株。在室内用‘渭薯1号’进行活体测定，瑞毒霉设0．01，0．1，1，10，100，1000mol／L等6个浓度梯度和1个空白对照，结果表明：有33．3％的菌株对瑞毒霉表现高度抗性，43．9％的菌株表现为中度抗性。抗性的发生往往是伴随这个地区连续使用瑞毒霉后而出现的。

Resistance to Metalaxyl in Phytophthora infestans in Populations in Potato Crops

Samples of Potato leaves and tubers with late blight were collected in Weichang,Zhangjiakou of Hebei, Keshan of Heilongjiang, Neimeng and Gansu Provinces in 1994. 66 isolates were obtained, tested by spores inoculated on potato tuber disks dipped into the solutions of metalaxyl at different concs. The nurnber of sporangia had been detected after 7 days. 33. 3% isolates appeared to be high resistant, 43. 9% isolates intermidally resistant. Occurrence of resistance was accompanied by using of metalaxyl in these areas.