Thebiotic function of communities of saprophytic fungi in the soil, rhizosphere, planospohere and roots of clover, orchard grass and their mixed cultures in respect to selected pathogenes of clover was examined. The pathogens were <i>Fusarium oxysporum</i> f. sp. <i>trifolii</i> and <i>Sclerotinia trifoliorum</i>. These communities were not able to resist <i>Fusarium oxysporum</i> f. sp. <i>trifolii</i>. However, most of the components of these communities limited the development of <i>Sclerotinia trifoliorum</i>.