Biological control of major fungal causal agent of root and crown rot of bean in Zanjan province with antagonistic bacteria

Root and crown rot of bean caused with Fusarium solani, Rhizoctonia solani and Fusarium oxysporum, is one of the important diseases of bean in Zanjan province. Using native biocontrol agents integrated with chemical agents is one of the effective management strategies. This is also important to choose control methods effective against all major fungal pathogens and mixed contamination of bean, with them. This research was conducted to study synergistic effect of three major fungal pathogens and biocontrol effects of some native rhizobacteria on disease. During the mid-summer of 2011, 46 bacterial isolates were obtained from bean rhizosphere in Zanjan bean fields. Two isolates of each three fungal species (pathogenic on bean) were also received from mycology collection of Zanjan University. Two isolates of Rhizobacteria were chosen as the best biocontrol agents against all three fungi in terms of production of antibiotic, volatile metabolites, HCN and protease and selected for in-vitro antagonistic experiments. Greenhouse results showed that, seed treatment of bean with bacteria, decreased the disease and increased some vegetative factors of the plant. There was synergistic effect among the fungal species.