Identification and characterization of the fungus Dothiorella sarmentorum on necrotic shoots of declining ash in Slovakia

Formerly, before the current Hymenoscyphus fraxineus epidemic, symptomatic ash twigs were habitually colonized by fungi occurring occasionally in the early stages of ash diseases. Some of these fungi are endophytes or facultative parasites. The segments of diseased shoots of the studied trees were collected from a seed orchard situated in southwest Slovakia. The frequently isolated fungus Dothiorella sarmentorum was identified microscopically and characterized with the aid of morphological keys. The disease symptoms comprise wood cankers, bud necrosis, and shoot and branch dieback displayed through bleached, necrotic or discoloured canes in infected trees. Despite the Dothiorella species has not yet been recognized to have significant economic consequences, the cumulative effects of various stressful biotic and abiotic factors may induce disorder and decline of ash trees in Slovakia.