Biological control of bacterial wilt (Ralstonia pseudosolanacearum) in tomato (Solanum lycopersicum) using an avirulent strain, Bacillus sp., and Pseudomonas fluorescens

Bacterial wilt disease, caused by Ralstonia pseudosolanacearum, threatens tomato cultivation due to the pathogen's soil-borne nature, high genetic variability, wide host range, and potential for severe yield loss. Utilizing avirulent strains of R. pseudosolanacearum and antagonistic bacteria emerges as a promising biocontrol strategy for managing R. pseudosolanacearum, given their shared environment in soil. This research used a completely randomized design with 4 treatments, involving 3 different species of biocontrol agents: Pseudomonas fluorescens, Bacillus sp., and avirulent strain of R. pseudosolanacearum. The results showed that all biocontrol agent treatments inhibited the growth of R. pseudosolanacearum and reduce the development of bacterial wilt disease in tomatoes. Avirulent strains of R. pseudosolanacearum showed the most significant results in delaying the development of bacterial wilt disease with an incubation period of up to 13 days, suppressing the disease severity to 18.67%, disease incidence to 26.67%, infection rate of 0.0037 unit/day, and lowest AUDPC value. Furthermore, based on plant growth parameters, all antagonistic bacteria showed promising results in promoting tomato height and number of leaves. This comprehensive exploration underscores the potential of avirulent strains and antagonistic bacteria, not only in inhibiting bacterial wilt but also in enhancing the overall growth and resilience of tomato plants.