Chalara fraxinea sp. nov. associated with dieback of ash (Fraxinus excelsior) in Poland

Summary A new species of the hyphomycete genus Chalara is described. It has been frequently isolated from stems and branches and sometimes also from roots of wilting and dying Fraxinus excelsior in Poland. It differs from previously described species of Chalara by its small, short cylindrical phialoconidia extruded in chains or in slimy droplets, morphological features of the phialophores and by colony characteristics. It is non-tolerant to cycloheximide.