中文摘要：

为了减少葡萄霜霉病在经济上造成的损失，采集湖南、福建、江西三省的不同地区、不同葡萄品种的19份葡萄霜霉病菌，检测了它们的孢子囊大小和在‘户太八号’、‘夏黑’、‘醉金香’、‘紫秋葡萄’、‘维多利亚’5个不同葡萄品种的致病力差异。通过保湿培养病原菌，再接至健康叶片上，根据孢子萌发法测长度和叶盘法测其致病力。结果表明，采自不同葡萄品种的霜霉病菌孢子囊大小存在一定的差异，来源于‘刺葡萄’的病原菌孢子囊明显大于来源于‘巨峰’、‘红地球’上的霜霉病菌孢子囊；来源于江西的菌株致病性普遍较强，而来源于湖南的菌株致病性普遍较弱。欧美杂交种葡萄，如‘户太8号’、‘夏黑’、‘醉金香’，其病情指数相对较低；欧亚杂交种和东亚种葡萄，如‘维多利亚’，‘紫秋葡萄’，其病情指数相对偏高。上述结果表明，采集自不同寄主的葡萄霜霉病菌的致病力和孢子囊大小均存在一定程度的分化。

英文摘要：

The aim is to reduce the economic loss of Plasmopara viticola. 19 accessions of Plasmopara viticola from different grapes were collected from different areas in Hunan, Fujian and Jiangxi. The sporangia size was determined, and the differences of pathogenicity in ＇ Hutai No. 8＇, ＇Summer Black＇, ＇Zuijinxiang＇, ＇ Ziqiu Grape＇ and ＇Victoria＇ were detected. The pathogenic bacteria were cultivated by moisture culture, and then were inoculated to the healthy leaves. The length was detected by sporangium germination method and the pathogenicity was determined by leaf-disc method. The results showed that the size of downy mildew bacterium sporangium from different grape varieties was ＇ Spine grape＇ was obviously greater than that of ＇ Kyoho different. The pathogenic bacteria sporangium from Grape＇ and ＇Red Earth＇. The bacterial strain from Jiangxi had generally stronger pathogenicity, but the bacterial strain from Hunan had generally weaker pathogenicity. European-American cross species grape, such as ＇Hutai No. 8＇, ＇Summer Black＇ and ＇Zuijinxiang＇ had relatively low pathogenicity. European-Asian cross species and East Asian species, such as ＇Victoria＇ and ＇Ziqiu Grape＇ had relative high pathogenicity. The above result indicates that there is a certain differentiation in the pathogenicity and sporangium size of downy mildew collected from different hosts.