中文摘要：

为有效治理浙江省杭州地区桑树上严重发生的新病害，开展了病原及其特性研究。从临安市和桐庐县的青枯桑树上分离出15株致病细菌，经25项主要细菌学特性、菌落形态、致病性、Biolog、脂肪酸分析、RAPD-PCR鉴定及与4株标准菌株比较，证实了这种桑青枯病是由Ralstonia solanacearum引起，属于生化型Ⅴ和Ⅳ，它们在15株分离菌中分别占73．3％和26．7％。同时，在该病原细菌的鉴定中，建立了简便易行的桑青枯病病原细菌致病性测定新方法。

英文摘要：

The causal organism of mulberry wilt and its characteristics were studied for effective management of the disease which severely occurred recently in Hangzhou Region of Zhejiang Province, China. Fifteen bacterial strains were isolated from the samples of bacterial wilt infected mulberry plants in Tonglu and Lin ＇an counties of the province. They were identified as Ralstonia solanacearum after 25 items of bacteriological tests, colony morphology, pathogenicity test, Biolog and FAME analysis, RAPD-PCR test and compared with the 4 standard reference strains. It was confirmed that R. solanacearum is the causal organism of the mulberry wilt and demonstrated that except Biovar V certain amount of Biovar IV also exists in mulberry, which was 73.3% and 26.7% of the 15 isolates, respectively. A new simple and reliable method for mulberry pathogenicity test of the bacterium was established in this study.