In vitro screening of Bacillus subtilis isolates against Rhizoctonia solani, the causal agent of root rot of chilli

Abstract

Bacillus subtilis a gram positive, endospore forming bacteria play a major role in biocontrol and PGPR activities. Thirty isolates of B. subtilis were obtained from different rhizosphere soil samples from different parts of North Eastern Karnataka region. All the isolates were rod shaped, positive for gram reaction, green coloured colonies were grown on Hichrome Bacillus agar medium based on these tests isolates were confermed as Bacillus subtilis. All the isolates showed varied levels of antagonist activity in vitro against Rhizoctonia solani, the causal agent of root rot of chilli. Among different isolates, BS16 showed highest 46.58 per cent inhibition followed by BS 30 (44.97 %) and least inhibition of mycelial growth of 12.85 per cent was observed in case of BS17 compared to check isolate with 38.55 per cent inhibition of mycelial growth of R. Solani. The B. subtilis strains were isolated, identified and used as a promising natural bioagent in chilli disease management strategies.