Biocontrol efficacy of bacillus subtilis formulations against damping-off in vegetable nurseries

Abstract:

Can biological agents replace chemical fungicides for managing damping-off in vegetable nurseries? This research evaluated two Bacillus subtilis strains (BS-12 and BS-27) formulated in talc and vermiculite carriers against Pythium aphanidermatum and Rhizoctonia solani in tomato, pepper, and cucumber nurseries at the Universidad Agraria de Castilla, Valladolid, Spain, across two seasons (2022–2023). A randomized block design with seven treatments and three replications was used. Treatments included individual and combined seed treatment (10 g kg⁻¹) and soil drenching (5 g L⁻¹), a metalaxyl check, and an untreated control. The combined BS-12 and BS-27 vermiculite formulation reduced damping-off by 69.9% and raised seedling vigor indices by 38.6% over the control. Vermiculite carriers retained higher viable counts (6.5 log CFU g⁻¹) than talc (5.3 log CFU g⁻¹) after eight weeks of storage. These findings indicate that dual-strain B. subtilis formulations offer a practical alternative to chemical seed treatments for nursery disease management.