Effect of Bacillus polymyxa seed treatments on control of black-rot and damping-off of cauliflower

A strain of Bacillus polymyxa, BP1, isolated from cauliflower seeds, inhibited in vitro a wide range of microorganisms. The studies of sterilized bacterial culture supernatant suggested that antagonism was due to the production of antibiotics and indicated that the strain has potential as a biological control agent for plant disease. The number of Xanthomonas campestris pv. campestris cells per plant was significantly reduced by treating infested seeds with BP1, but not eliminated. BP1 reduced damping-off due to Alternaria brassicicola when it was applied to infested seeds in the greenhouse. The effectiveness of BP1 against the fungus was also observed in nursery conditions. No significant in vivo effect was noticed against Rhizoctonia solani.