Volatiles from Bacillus siamensis H30-3 Reduce Grey Mould in Pepper Plants

Rhizobacteria <oi>Bacillus siamensis H30-3 exhibited in vitro antifungal activity against Botrytis cinerea, causing grey mould in pepper plants. Mycelial growth of B. cinerea was restricted under co-cultivation with B. siamensis H30-3 and exposure to volatiles from B. siamensis H30-3. Conidial germination of B. cinerea was also delayed by volatiles produced by B. siamensis H30-3. The volatiles-mediated limitation in the mycelial growth and conidial germination was more evident by B. siamensis H30-3 grown on media containing 0.6% agar concentration than 1.5%. Grey mould lesion on the detached pepper leaves was reduced by volatiles from B. siamensis H30-3, and a higher disease protection efficacy was found by B. siamensis H30-3 grown on media containing 0.6% agar concentration than 1.5%. B. siamensis H30-3 volatiles were enough to decrease grey mould in pepper seedlings. These results suggest that B. siamensis H30-3 can be applied as a biological control agent for the pepper grey mould.