Methods for the Study of Verticillium chlamydosporium in the Rhizosphere

Methods for screening isolates of the nematophagous fungus, V. chlamydosporium, for their ability to colonize the surface of plant roots are described. Significant differences in the extent of colonization were observed in sterile conditions and in soil; plant species and cultivars also differed in their ability to support a selected isolate of the fungus. Although fungal density could be estimated using a semi-selective medium, it was not possible to separate differences in vegetative growth from differences in sporulation. There was a weak positive correlation between estimates of fungal density on the roots of plants grown in sterile conditions and the extent of hyphal growth measured by direct observation.