Natural infection of Fraxinus angustifolia by Hymenoscyphus fraxineus in Slovakia.

The fungus Hymenoscyphus fraxineus is responsible for dieback of common ash (Fraxinus excelsior) and in some parts of Europe also of narrow-leaved ash (F. angustifolia). The first symptoms of ash dieback have been recorded on F. excelsior in Slovakia since 2004. This study reports about the first natural occurrence of H. fraxineus on F. angustifolia in Slovakia. The field investigation was carried out in 2014. The segments of diseased shoots and last year's petioles were collected in clonal seed orchard situated in southwest part of the country. The fungus was isolated from infected host tissue and identified using molecular techniques (DNA extraction from pure cultures and apothecia, conventional PCR).