METHODS FOR THE STUDY OF VERTICILLIUM-CHLAMYDOSPORIUM IN THE RHIZOSPHERE

Methods for screening isolates of the nematophagous fungus, V. chlamyd osporium, 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 cultiva rs also differed in their ability to support a selected isolate of the fungus. Although fungal density could be estimated using a semi-selec tive medium, it was not possible to separate differences in vegetative growth from differences in sporulation. There was a weak positive cor relation between estimates of fungal density on the roots of plants gr own in sterile conditions and the extent of hyphal growth measured by direct observation.