Optimizing the fermentation conditions for Bacillus sp. combination CL-8 thalli with cooperative and synergistic action and its biocontrol efficacy

The fermentation conditions for antagonistic combination Bacillus sp. CL-8 thalli were studied through single factor and orthogonal experiment. It was demonstrated that the optimum fermentation media contained corn meal 1%, bean pulp 1%, honey 0.5%, NaCl 0.5%，Na2CO3 0.2%, K2HPO4 0.2%, MgSO4?7H2O 0.02%, CaCO3 0.1%, MnSO4?H2O 0.01% and FeCl3 0.01%. The favorable fermentation conditions are as follows: the proportions of Bacillus sp. SL-13, Bacillus sp. SL-14 and Bacillus sp. SL-44 are 2︰1︰2 and initial pH value of the medium is 7.0. Bacillus sp. combination CL-8 thalli cultured under the optimum conditions was also used to inhibit Rhizoctonia solani and control damping-off of processing tomato seedling in the field. The biocontrol efficacy was 55.53%，which was much better than that by three single Bacillus sp. SL-13, SL-14 and SL-44.