Enhancing the Biocontrol Potential of Compost and Vermicompost Tea with <i>Bacillus</i> spp. Against Bacterial Wilt of Tomato

Abstract The ability to suppress Ralstonia solanacearum using compost and vermicompost tea enriched with Bacillus spp. was assessed both under in vitro and in vivo conditions in this study. Tomato is one of the most important vegetables in the world, which are highly susceptible to bacterial wilt disease. Three distinct media were used to evaluate the antagonistic efficacy of 21 Bacillus isolates, of which 14 isolates showed an antagonistic effect and three isolates, B 1 – Bacillus megaterium (B40DhanSat), B 2 – Bacillus cereus (BD49IslamSat) and B 3 – Bacillus cereus (EB36KalSat), exhibited the highest inhibition percentage, particularly in vermicompost tea media. Vermicompost and compost tea were enriched with three promising antagonistic isolates and used as treatments on the tomato variety named ‘Roton’. Disease incidence and severity [%] measured at 30, 60 and 90 days after transplanting (DAT) showed that T 4 (soil + vermicompost tea + B 2 , 8%), T 10 (soil + vermicompost tea + B 1 + B 2 + B 3 , 7.9%) and T 12 (Bactroban,7.37%) had the highest disease suppression ability than control treatment at 90 DAT, following the application of total twelve treatments. Data recorded on vegetative, reproductive, as well as biochemical parameters at various growth stages showed the best performance of T 4 , T 10 and T 12 treatments. Thus, it can be concluded that compost and vermicompost tea fortified with Bacillus spp. can have a potential suppressive effect on the bacterial wilt pathogen of tomato by reducing mycelial growth. Therefore, farmers may be guided to use eco-friendly organic amendments, ensuring efficient disease management without adverse effects on human health or environmental safety.