European ash (fraxinus excelsior) dieback – situation in Europe and Ukraine

Publications, mainly for 2013–2014, and authors' own data on ash dieback, caused by Hymenoscyphus fraxineus (anamorph Chalara fraxinea) are reviewed. Disease is known now in over 25 countries of Europe, since 2010 – in Ukraine. The presence of pathogen in Kharkiv, Sumy, Poltava, Kyiv and Zhytomyr regions is proved by molecular methods. The main symptoms of disease are: quick successive crown dieback, necrotic spots on the bark of shoots, discoloration of wood and leaves, leaf necrosis, premature leaf-shedding, stem necroses. Investigations are directed on study of pathogen development, virulence of certain fungi isolates, susceptibility of certain species and populations of Fraxinus sp. to infection, as well as on development the guidelines for prevention of negative consequences of disease spread for forest management and forest ecosystems. Key words: Fraxinus sp., ash dieback, Hymenoscyphus faxineus (Chalara fraxinea), guidelines for forest management.