Effect of Bacillus velezensis 8-2 on Fire Blight Disease

Fire blight is one of the devastating bacterial diseases that occur in the rose family plants such as pears and apples. The causative bacterium is Erwinia amylovora, and it is known to be difficult to control. In this study, we prepared a suspension concentrate for microbials (SM) formulation using the eco-friendly microorganism Bacillus velezensis 8-2 and evaluated the control efficacy of B. velezensis 8-2 SM against fire blight of apples. This strain has been previously reported to produce difficidin, oxydifficidin, iturin A, fengycin, and surfactin, which have antimicrobial activity against plant pathogenic bacteria and fungi. B. velezensis 8-2 SM exhibits a strong antibacterial effect against fire blight, suggesting that these metabolites showed antimicrobial activity against E. amylovora. The B. velezensis 8-2 SM treatment group showed a similar level of control efficacy to the streptomycin wettable powder control group in both seedling and mature tree tests, and exhibits significantly higher activity than commercial biopesticide control group. In conclusion, B. velezensis 8-2 SM is an eco-friendly fire blight control agent based of antibacterial activity, which has industrial value in that it dramatically improves effectiveness compared to existing biopesticides and can overcome the limitations of antibiotics.