Solid-state fermentation plus extrusion to make biopesticide granules

Five fungal biocontrol agents useful in agriculture were grown on rice flou r in plastic bags. The flour, infested with Colletotrichum truncatum, an Al ternaria sp., Paecilomyces fumosoroseus, or atoxigenic Aspergillus flavus a nd A. parasiticus, was mixed with wheat flour, kaolin, and water and extrud ed into granules. The inoculum survived extrusion and fluid bed drying at 5 0 degrees C 3-92 times better than inoculum produced in liquid fermentation . Depending on the agent, the high level of flour infestation permitted a 1 :9 to 1:1600 dilution to yield the 1x10(6) cfu/g in the final product which is usually needed for biocontrol efficacy.