Inoculum of the biocontrol agent Gliocladium virens for treatment of cotton seed has, in the past, been produced in still culture on moist millet. It can, however, be produced in an aqueous liquid culture containing 5% ground millet, a technique that is more amenable to commercial mass production of the product. Aerated cultures are grown at 25 C for 6 days, then the solids are pelletized from the medium by centrifugation, air dried, and ground to a fine powder. The powder is coated on cotton seed with the aid of a latex sticker. This biocontrol product contains a much higher proportion of chlamydospores and higher concentrations of antibiotics than does that produced by the former method. The biocontrol efficacy of the product from liquid culture is initially as good or superior to that of the moist millet culture, and in storage it retains its biocontrol efficacy and viability for a longer period of time. Treatment of cotton seed with G. virens/millet product has resulted in better stands, more vigorous plants and higher yields.