First report of Chalara fraxinea on common ash in Italy.
In many European countries, the anamorphic C. fraxinea (teleomorph Hymenoscyphus albidus) is responsible for a severe and rapidly spreading dieback of common ash (Fraxinus excelsior) since it was first reported in Poland. Recently, this disease was added to the EPPO Alert List and the NAPPO Phytosanitary Alert System. Symptomatic trees were observed in a 1.8-ha ash-maple forest in the northeastern Italy (782 m above sea level) along the Italo-Slovenian border in July 2009. Symptoms were found on approximately 10% of mature common ash and 70% of the seedlings. Main symptoms were shoot, twig, and branch dieback, wilting, and bark cankers. Fungal fruiting bodies were not found on or near the canker surface. Furthermore, longitudinal and radial sections through the cankers revealed gray-to-brown xylem discoloration. The causal agent was identified as C. fraxinea based on cultural and morphological characteristics, as well as pathogenicity tests. This is thought to be the first report of C. fraxinea in Italy.