Hymenoscyphus fraxineus on Fraxinus excelsior in Slovakia: distribution and mating types.

Hymenoscyphus fraxineus causes ash dieback in Europe and threatens the future existence of Fraxinus excelsior in large parts of its natural distribution range. In this study, we report the first documented distribution of the pathogen on the most common ash species F. excelsior in Slovakia, identified molecularly using species-specific primers and based on sequencing of the ITS region of rDNA. Analysis of the mating type genes of H. fraxineus isolates revealed the presence of both mating types in Slovakia. Hymenoscyphus fraxineus-positive trees were recorded in 70 localities with different types of management in different parts of the country, mainly in forest stands. The results indicate the widespread distribution of H. fraxineus across the entire country, wherever the host is present. [ABSTRACT FROM AUTHOR]