Effectiveness of Bacillus and Pseudomonas Strains in Biological Control of Common Bacterial Blight Disease in Common Bean (Phaseolus vulgaris L.)

In this study, the biological control of common bacterial blight disease, which causes significant yield losses in bean plants, was investigated with bacterial strains isolated from different sources. In vitro biocontrol effect of 121 bacterial strains against Xanthomonas citri subsp fuscans was tested on a medium containing King's B Agar. It was found that 10 of the strains showed antibacterial activity by forming an inhibition zone ranging from 1.60 to 2.66 cm. Plant growth promoting properties such as nitrogen fixation, phosphorus and potassium solubility of the strains found successful in vitro were determined. Additionally, pectolytic activity and hypersensitivity reactions to tobacco were tested. The pot experiment was established according to the randomized plots design with 8 applications with 3 replications. As a result of the experiment, it was determined that Bacillus subtilis strain BSU-37 was the most effective strain (83.43%) in biocontrol of the disease. B. velezensis strain BSU-26, B. amyloliquefaciens strain BSU-14 and B. pumilus strain BSU-22 were determined to be successful strains in disease control with 75%, 59% and 58.46% effect values, respectively. In the same study, the effect of bacterial strains on plant development was evaluated. When the plants treated with only Xcf were compared with the plants treated with pathogen + antagonist bacteria, it was seen that the antagonist bacteria strains prevented plant growth despite the pathogen. It was determined that the Xcf + B. subtilis strain BSU-37 application gave the best results compared to the control group in terms of all parameters examined.