Description

Abstract: Three components of dispersal important to the colonization of a soil matrix by fungal parasites of sclerotia were identified and measured: the percentage of the carrier granules from which hyphae extended into soil (PGH), the mean number of hyphae extending into soil from each granule (MNH), and the mean length of the hyphae extending into soil (MLH). Factors that influence dispersal were determined for strains of Gliocladium roseum, Thielavia terricola, and Trichoderma spp. The source of carbon, the source of nitrogen, and the C:N ratio of the carrier substrate significantly (p?=?0.001) affected all three components of dispersal subsequent to the placement of the carrier granules in nonsterile soil. Increased C:N ratio (12:1 to 80:1) and increased molar concentrations of both carbon and nitrogen sources (0.02 to 0.18?M maltose and 0.006 to 0.024?M arginine) gave increased PGH (17 to 82%), MNH (1 to 5 hyphae per granule), and MLH (275 to 782??m in 24?h) for G. roseum. Similar increases in PGH (80 to 100%), MNH (5 to 10 hyphae per granule), and MLH (983??m to too long and interwoven to measure after 24?h) were observed for Th. terricola. PGH and MNH were greater at high soil moistures (?0.1 and ?0.33 bars matric potential; 1 bar?=?100?kPa) than at low soil moisture (?10 bars).