Fungi in foliage and shoots ofFraxinus excelsiorin eastern Ukraine: a first report onHymenoscyphus pseudoalbidus

Summary In eastern Ukraine, the first symptoms of dieback on common ash ( F raxinus excelsior ) were observed in 2010, as sparse flushing of leaves, bark necrosis and wood discoloration of shoots. The aim of this study was to assess possible causal agents of the damage by studying fungal communities in both symptomatic and healthy‐looking shoots, and leaf petioles. Field sampling was carried out in 2010 in Kharkiv and Sumy regions in eastern Ukraine and included 68 segments of symptomatic shoots, 68 segments of healthy‐looking shoots and 240 segments of petioles. DNA isolation from individual segments and direct sequencing of fungal ITS rRNA resulted in 430 fungal sequences representing 29 distinct taxa. Results showed that H ymenoscyphus pseudoalbidus – the primary causal agent of ash dieback in Europe – was present at low proportion (5.6%) in symptomatic shoots. Other more frequently detected fungi were E picoccum nigrum, V enturia fraxini, C olletotrichum truncatum, A ureobasidium pullulans, A lternaria alternata, A lternaria sp. and L ophiostoma corticola . In conclusion, the study reports on the first incidence of ash decline in the Ukraine and other possible causal agents of damage which may help to evaluate and forecast the future situation with F . excelsior stands in the region.