Abstract: In the field experiments during 1986-1988, seedlings of grapevine and sunflower infected with the crown gall pathogen, Agrobacterium tumefaciens, were immersed with the suspension of A. radiobacter HLB-2 strain. The inhibiting effects to the artificially infected disease on grapevine and sunflower and the naturally infested grapevine were 85.6%, 83.5% and 100%, respectively. When the crown galls on grapevines were hand-removed and treated with the HLB-2 suspension, the control effect was 73.1-88.6%.