broad host range and the high survival rate of sclerotia under various environmental conditions (Groth et al., 2006). So far, no rice variety completely resistant to this fungus has been found, although extensive evaluation of rice germplasm has been conducted (Oard et al., 2004). In the absence of a desired level of host resistance, the disease is currently managed by excessive application of chemical fungicides, which have drastic effects on the soil biota, pollute the atmosphere, and are environmentally harmful. Some potentially effective fungicides are highly phytotoxic to rice and, if the disease is not severe, these fungicides may reduce yield (Groth et al., 1990). It is difficult to achieve control through host resistance or fungicides, therefore, biological control may be effective in minimizing the incidence of sheath blight (Das and Hazarika, 2000).