Efficacy of a simple liquid culture of Bacillus megaterium in suppressing grain discoloration disease of rice (Oryza sativa)

Abstract

Grain discoloration (GD) of rice (Oryza sativa) is a disease complex that occurs on rice panicles as a result of infection by various fungi. Bacillus megaterium, a bacterial antagonist that is effective against sheath blight of rice, was cultured using either nutrient broth, potato dextrose broth or a common household flavour enhancer. Preliminary data from a single experiment suggested that all three cultures supported growth of the bacterium. Spraying diluted bacterial nutrient-broth culture onto rice (var. RD 31) three times (41, 84 and 96 days after transplanting) reduced the mean severity of GD as a result of the field trials from three consecutive growing seasons. The spray did not affect the percentage germination of the rice seeds after they had been stored for three months in the laboratory at room temperature (26°C-32°C).