The bacterium Bacillus subtilis has been studied for several years as a biological control agent as well as a plant growth promoting rhizosphere inhabiter. Studies conducted on peanuts indicate that seed treatment with this organism can provide protection of the taproot from Rhizoctonia solani, as well as stimulation of plant emergence, mid-season vigor, and root growth. Yields are consistently improved with treatment, but greater improvements occur if used on peanuts planted in cool soils, and/or in fields with a history of legumes in the past two cropping seasons.