Abstract: One thousand two hundreds seventy four bacterial isolates were obtained from paddy soil, sclerotia of Rhizoctonia solani, sheath blight (ShB) lesions and healthy rice plants. Their antagonism to Rhizoctonia solani were tested in vitro. Sixty one strong antagonistic strains, 727 moderate and weak antagonistic strains and 486 non-antagonistic strains were 4.8%, 57%, and 38.1% of the total, respectively. Twenty four strains were used for biocontrol of ShB at rice tillering stage of rice in pots, 6 strains with over 60% of control effect on ShB were further tested biocontrol in the field plots. The results indicated that strain B-916 was the best in control effect on rice ShB in the field. Performance test of B-916 of biocontrol on ShB was continuously carried out during 1994-1997 at three sites (Jiangyan, Wujiang, and Jurong Cities, Jiangsu Province), the results showed that ferment product of B 916 which could effectively control rice ShB infection under field conditions, has 50.0% to 81.9% of control effect on ShB.

Key words: biocontrol, antagonistic bacteria, rice sheath blight

摘要： 从稻田土壤、纹枯菌菌核、病斑和水稻植株上共分离获得1437个细菌分离物。在离体条件下测定它们对水稻纹枯菌的拮抗能力。其中拮抗能力强的菌株61个，占4.8％；没有拮抗作用的菌株有486个，占38.1％；其余57％的菌株是略有拮抗作用。24个菌株对水稻纹枯病的防治效果的盆栽生物测定表明，其中有9个菌株的防效在60％以上。挑选了6个菌株在田间进一步测试其防效，结果证实了B916对水稻纹枯病的防治效果最好。1994～1997年连续4年在姜堰、吴江和句容3个基点示范推广使用B916发酵液防治水稻纹枯病，累计面积为2000 hm2以上。大田示范试验结果表明，拮抗菌B916发酵液能够有效地控制水稻纹枯病的为害，防效为50.0%～81.9%。

关键词: 生物防治, 拮抗细菌, 水稻纹枯病, 枯草芽孢杆菌