Bio control efficacy of Bacillus subtilis against Tomato damping-off incited by Pythium aphanidermatum

Tomato (Solanum lycopersicum L.) is a significant vegetable crop that frequently falls victim to various diseases, resulting in substantial crop losses. Among these fungal diseases, damping-off caused by Pythium aphanidermatum is a major issue in tomato nurseries, posing a significant challenge to tomato production. This study aimed to address the problem of tomato damping-off caused by Pythium aphanidermatum by utilizing bacterial antagonists, specifically Bacillus subtilis. In a controlled laboratory setting, the effectiveness of Bacillus subtilis strains was evaluated against the pathogen. Among the ten Bacillus subtilis strains examined through dual culture, Bs7 demonstrated the highest level of inhibition, reaching 65.46%. Additionally, ten native isolates of Bacillus subtilis were screened for their ability to antagonize P. aphanidermatum using in vitro techniques, including the poisoned food technique, agar well method, and paper disc method. The culture filtrates of the bioagent Bacillus subtilis (Bs7) effectively suppressed the mycelial growth of Pythium aphanidermatum when applied at a concentration of 30%.