Abstract:Rice seed is one of the most important resources of biocontrol agents. Its necessary for us to understand distribution of the antagonistic bacteria against sheath blight of rice under different culture patterns and their characteristics in order to gain satisfied biocontrol agents in Zhejiang Province. A field survey and isolation of the antagonistic bacteria was conducted. It was showed that the isolation frequency of the antagonistic bacteria from rice seeds of direct broadcast-seeding was significantly higher than those from direct row-seeding and transplanting. Thirteen strong antagonistic bacteriae against Rhizoctonia solani were screened in vitro from 1 000 bacterial isolates obtained from 3 different culture patterns of rice. Pathogenicity test showed that isolate S270262 produced lesions on rice plant and other 12 strains were non-pathogenicity,which were used for rice seed bacterization against R.solantiv in the screening-house and greenhouse and spraying in paddy field and identified by Biolog. The results showed the 10 strains had growth promoting effect on rice plant and 2 inhibiting the growth. Strain T300363, S300265 and S90132 had better performance in pot and field plot experiments. They were identified by Biolog as Salmonella subsp. 1 G, Pseudomonas aeruginosa and Pseudomonas spp.