Potential of Laetisaria arvalis for the biocontrol of Rhizoctonia solani

Bran preparations of the fungus Laetisaria arvalis isolates LA-1, OK-60, OK-160, OK-206 and ZH-4 reduced survival and saprophytic growth of Rhizoctonia solani (AG-4) in soil. They also prevented damping-off ( R. solani) of cotton, sugar beet, lettuce and radish in the greenhouse. The six isolates of L. arvalis grown on sterile wheat bran moistened with water and incubated for 5–15 days before addition to soil at a rate of 0.5% (w/w), were equally effective in reducing R. solani inoculum. In general, 15 day old preparations were as effective as 5 day old preparations. 7 Day old bran preparations of various L. arvalis isolates added to pathogen-infested loamy sand soil at a rate of 0.5% (w/w), prevented post-emergence damping-off of cotton, sugar beet, radish and lettuce. Several treatments resulted in seedling emergence and survival similar to those in natural soils not supplemented with R. solani. Preparations of L. arvalis also prevented damping-off of cotton in three other soils.