Fungi associated with stem collar necroses of Fraxinus excelsior affected by ash dieback

Abstract In recent decades the vitality and physical stability of European ash trees in Germany have been reduced by dieback, especially when associated with stem collar necroses rots. This study was carried out to investigate composition fungal communities necroses. Filamentous fungi were isolated from 58 nine forest stands northern, eastern, central Germany. Obtained isolates identified a genus or species level means morphological molecular analyses. total 162 morphotypes including endophytic, saprotrophic, pathogenic isolated. For 33 found no prior reports Fraxinus excelsior recognised, Cryptostroma corticale Diplodia sapinea . None at all studied sites, though fraxini most common fungus regard frequency within , occurring seven sample sites. is followed Hymenoscyphus fraxineus Armillaria spp., Neonectria punicea Diaporthe cf. eres Fusarium lateritium Paracucurbitaria sp. order isolates. The aforementioned are characterised analysed respect their occurrence influence site conditions on described for five intensively sampled sites minimum (Schwansee, Rhüden, Berggießhübel, Satrup, Schlangen). sampling Schlangen further subdivided into four subplots different positions terrain. remaining extensive either one two trees, respectively, (Oranienbaumer Heide, Woltershausen, Wolfenbüttel, Neuhege). Over symptomatic tissue similar concerning frequent fungi, but vary greatly according singularly fungi.