Soil-borne plant pathogenic fungi in relation to some collembolan species under laboratory conditions

Interactions between springtails (Onychiurus armatuss, O. tuberculatus, Fol somia candida) and plant pathogenic fungi (Gaeumannomyces graminis var. tri tici, Fusarium culmorum, Bipolaris sorokiniana and Rhizoctonia cerealis) li ving in the same soil layer were investigated under laboratory conditions. The fungi are responsible for the foot and root disease complex of winter c ereals and can cause serious reduction in yield. Since these species coexis t in agricultural soils, feeding preference tests were performed in such a way that the springtails were allowed to interact simultaneously with all t he tested fungi. O. armatus, O. tuberculatus and F. candida fed on the myce lia of G. graminis var. tritici, F. culmorum and R. cerealis: in the first hours of the trials individuals of all springtail species distributed thems elves among the colonies, though moving from one to the other. Subsequently F. culmorum mycelium became the preferred food of all species tested; howe ver, the other two fungi continued to be consumed. Mycelia of G. graminis v ar. tritici, F. culmorum and R. cerealis were shown to be an adequate food source for reproduction of Folsomia candida. Bipolaris sorokiniana mycelium had both repellent and lethal effects on F. candida and O, armatus is, whe reas this fungus was lethal, although not repellent. for O. tuberculatus. L ong-term experiments on T. candida indicate that conidia of B. sorokiniana were eaten and proved to be a sufficient diet for reproduction.