Abstract: Six ectomycorrhizal fungi, Boletus edulis, B. sp., Suillus grevillei, S. luteus, Chroogomphus rutilus, Xerocomus chrysenteron, have demonstrated their strong abilities to inhibit the growth of some pathogens of plant roots, such as Fusarium oxysporium, F. solani, Rhizoctonia solani, Pythium aphanidermatum, P. ultimum and Agrobacterium tumefaciens in the lab since 1981.In this antagonism experiment, these mycorrhizal fungi were found to be able to destroy the vegetative mycelia of pathogens, and fed themselves on the hyphae fhis, inhibited the formation and germination of conidia, sporangia and sclerotia of pathogens. In the study of antagonistic mechanism, it seems that mycorrhizal fungi could secrete non-volatile active substances which caused the contraction and lysis of the protoplasm of pathogens such as A. tumefaciens even after high temperature treatment at 60℃ for 30 minates. Volatile active substances were also detected. Several mycorrhizal fungi could parasitize on the hyphae of R. solani with haustoria observed under scanning electron microscope.

Key words: Ectomycorrhizal fungi, The pathogen of plant root, Antagonism