Biological control of groundnut stem rot by Bacillus sp. strain S20D12

Stem rot caused by the soil-borne pathogen Scleoritum rolfsii Sacc. is a destructive disease which seriously causes yield loss of groundnut in Vietnam. In this study, the antagonistic bacterial strain Bacillus sp. S20D12, which was isolated from stem-base of groundnut plant in Vietnam, was evaluated for fungal inhibition in vitro and biological control of groundnut stem rot under nethouse and farmer field conditions. Results of the study showed that cell free filtrate of Bacillus sp. significantly inhibited S. rolfsii in potato dextrose broth. The Bacillus sp. S20D12 significantly reduced stem rot under nethouse condition. Subsequent field trials conducted in central Vietnam over 2 consecutive years showed that Bacillus sp. S20D12 significantly reduced stem rot disease, significantly and consistently enhanced pod yield with increases ranging from 18.3?21.2% relative to the untreated control plants.