Laboratory studies on the interactions between some species of Collembola and the most important pathogenic fungi of the foot and root of cereals were performed. Onychiurus armatus and Onychiurus tuberculatus actively grazed on the hyphae of Gaeumannomyces graminis var. tritici, Fusarium culmorum and Rhizoctonia sp. They did not have a higly specific feeding preference; they fed on the mycelium of all the three fungi even when present contemporaneously.Experiments carried out utilising another cereal pathogenic fungus, Bipolaris sorokiniana, indicate that its hyphae were repellent and produced one or more non-volatile metabolites that were lethal at least for some species of Collembola. Our investigations suggest that B. sorokiniana did not produce the toxic metabolite or metabolites throughout its entire life cycle. The substance(s) is/are produced when only hyphae are present, whereas we observed that Onychiurus pseudogranulosus actively fed on conidia that the forms only later.