Abstract
The pathogenicity of A. alternata, F. culmorum, F. oxysporum, F. solani, P. irregulare, and R. solani isolated from oats, spring vetch, and tancy phacelia mulch soil to Scorzonera hispanica L. in the conditions of a growth chamber was studied. The pathogenicity of these microorganisms was established on the basis of the number of emerged plants and their healthiness. The studied species considerably decreased the emergencies and healthiness of the seedlings, e.g. necrosis of sprouts and roots. Differentiated harmfulness of particular microorganisms isolates was observed within a given species. The isolates of P. irregulare and F. oxysporum proved to be the most severe for the seedlings, while A. alternata the least.