The inhibition activity was tested by dual culture method and microscope observation，and the
control efficacy of Bacillus subtilis NBF809 on tomato Corynespora leaf spot was investigated by pot experiment.
The results showed that NBF809 strain had good inhibition activity in dual culture. The distortion，swelling and
deformation of mycelium were observed under microscope. Result of pot experiment demonstrated that the control
efficacy of NBF809 strain on tomato Corynespora leaf spot reached 73.26%. Polymerase chain reaction was used
to detect antibiotics produced by NBF809 strain. These antibiotics were amplified to bacD，ituC，ituD，mrsM
and mycC 5 genes，involving respectively in the biosynthesis of 4 antibiotics：Bacilysin，Iturin，Mersacidin and
Mycosubtilin.