The ability of Thielaviopsis basicola to survive saprophytically
in soil was investigated using root tissue from susceptible
hosts as organic substrates. Inoculum densities were lower in
soils amended with root tissue than in nonamended controls after
2 and 4 weeks of incubation. The greatest decrease occurred in
soils containing the highest concentration of root tissue or in
soils in which root tissue included the soluble components of
the living root. Reproduction by T. basicola also was examined
in axenic media containing either killed root pieces or various
carbohydrates as the sole carbohydrate source. T. basicola
utilized killed root tissue as a carbohydrate source in axenic
media, particularly in cultures in which root tissue included
the soluble components. Enzymatic activities of T. basicola,
however, did not result in maceration of the root tissue. T.
basicola utilized sucrose and cellobiose, but did not utilize
structural carbohydrates such as cellulose, hemicellulose, or
pectin. Based on the absen