Effects of Bacillus subtilis on Pyricularia oryzae, causal agent of rice blast

Abstract

Antibiosis was the mechanism of antagonism showed by Bacilus subtilis against Pyricularia oryzae. Antibiotics secreted by B. subtilis were in vitro inhibitory to mycelial growth as well as to conidial germination. The antagonistic substances produced by B. subtilis were thermo-stable and they acted at low concentrations. In liquid medium with and without constant agitation, B. subtilis secreted metabolites in adequate concentration to inhibit totally mycelial growth of P. oryzae after one day of incubation. The capacity of B. subtilis to inhibit the mycelial growth of P. oryzae was not affected by fluorescent light and darkness, but the near ultraviolet light was prejudicial