Growth of Phymatotrichum omnivorum (P.o.) in Weswood silt loam and Brayon clay was measured using glass tubes (2.5 cm diam. x 53 cm) filled with the soils and inoculated at one end with sclerotia or with sorghum seed previously infested with P.o. Mycelial extension was measured under sterile and nonsterile conditions with or without the addition of several organic amendments or antagonistic microbes. The fungus exhibited linear growth in Branyon clay under sterile and nonsterile conditions whereas in the Weswood soil growth was linear under sterile conditions but reduced under nonsterile conditions and production of sclerotia was nearly eliminated. Organic amendments, with the exception of chitin, did not markedly reduce growth of the fungus. Growth was reduced slightly in tubes which had been amended with chitin and preincubated prior to inoculation with P.o. Bacterial antagonists failed to impede the growth of P.o. through the soil but growth was delayed in the presence of a gray-pigmented streptomycete.