Abstract: 240 isolates were obtained from wheat sheath infected with Rhizoctonia
cerealis using dilute plate technique and 11 of these isolates, Bacillus spp.
showed an tagonism to R. cerealis which causes wheat sharp eyespot. The inhibition zone of mycelial growth on PDA based on the fungus-bacteria pairing culture ranged from 6.0- 13.0 mm. The mycelial growth on the medium mingled
with bacterium was inhibited by 100% and having block zones in the plates of
Rb2, Rb13, Rb18, Rb23, Rb26 and Rb29. Rb2 and Rb26 were selected to be
goodan tagonists. The metabolites of Rb2 and Rb26 inhibited the mycelial
growth, their EC₅₀ were 2. 8% and 1. 8% respectively. The boiled metabolites
also demonstrated the good inhibition, their EC₅₀ were 310% and 2. 1% respectively. Sclerotia form ation as inhibited significantly by boiled metabolites, but less than the unboiled metabolites. The wheat seeds were soaked in the bacterial suspension and its metabolite, which was prepared from liquid culture and contained abou t 6. 8 × 10⁸ colony forming units ( cfu )/m l for 24 hat 20℃, and seedlings were infected with inoculum of R. cerealis. The results demonstrated that Rb2 and Rb26 were effective for controlling wheat sharp eyespot and so were their metabolites, which implied that Rb2 and Rb26 may inhibited the disease with seed bacterization or by the metabolites.