The Diagnosis of the Pathogen of Mulberry Bacterial Wilt in Zhejiang Province

One hundred and fifty-one bacterial strains were isolated from the roots and stems of wizened mulberry in Ling'an and Tonglu counties of Zhejiang Province.Pathogenicity test results show that all of the strains can induce the mulberry wilt,and the shape,size,dye-reaction and culture characteristics of the mulberry wilt were similar to those of the tomato bacterial wilt.Based on PCR results,125 bacterial strains were identified as Ralstonia solanacearum.Based on the symptom in farm,the mulberry wilt were diagnosed as bacterial wilt.Among them,16 typical strains were also classified as the physiological race 1 by Haywind's classification criterion,and 75% of which were Ralstonia solanacearum biovar Ⅴ,25% were Ralstonia solanacearum biovar Ⅲ.