Mycobiota of thin roots showing decay of Fraxinus excelsior L. young trees

The aims of the study were to identify the fungi associated with the decay of thin roots (1-5 mm) of 1, 3 and 15-year-old Fraxinus excelsior plants and to estimate the pathogenicity of certain fungi. In total, 400 fungal isolations were performed from which 334 cultures were obtained. Altogether, 26 species of fungi were identified. The following species were most frequently obtained, independently of plant age and origin: Alternaria alternata, Chaetomium globosum, Cryptosporiopsis sp., Fusarium oxysporum, F. solani and Cylindrocarpon destructans. The last three of these were then used in an inoculation test. F. oxysporum caused the death of over 80% of 2-month-old seedlings grown in boxes containing perlite and kept in a growth chamber.