Study on Biological Control of Botrytis cinerea by Bacillus subtilis Strains BS-208 and BS-209

To exploit the antagonistic bacteria against Botrytis cinerea, experiment was conducted for controlling tomato gray mold by Bacillus subtilis BS-208 and BS-209 in the greenhouse and field. Inhibition effect to conidia germination and mycelium growth were also assayed. The secretion of B.subtilis BS-208 inhibited over 44% the mycelium growth of B.cinerea. Fermentation liquor of strains BS-208 and BS-209 inhibited above 90% conidia germination after diluting 10 fold. The greenhouse experiment showed that the fermentation liquor and spore of BS-208 and BS-209 had above 75% control efficacy with inoculating after 24 and 48 h, but the secretion exhibited bad control efficacy. Two years experiment in the field indicated that the formulation of B. subtilis BS-208 and BS-209 could effectively control tomato gray mould. With the increasing of concentration its control efficacy became better and 800-fold treatment had the best control efficacy. After three times treatment with the 800-fold formulation continuously, the control efficacy reached above 74% and the effect of BS-208 was better than that of BS-209's.