Recent observations of sooty bark disease of sycamore maple in Prague (Czech Republic) and the phylogenetic placement of Cryptostroma corticale

The anamorphic fungus Cryptostroma corticale (Xylariaceae) causing sooty bark disease (SBD) of Acer pseudoplatanus has been reported within the past decade in several European countries. In the last decade, severe drought conditions during summer also resulted in an outbreak of SBD in park areas in Prague (Czech Republic). Trees with the typical syndromes were recorded in four localities in Prague. Some trees were also located in the alluvial plain of the Vltava River with groundwater available all year long. We suppose that the trees were stressed by full water saturation for several months after flood in 2012 and that SBD was triggered by anoxia and subsequent phytopththora root rot. Sterile fungi isolated from one tree and one lesion were identified as C. corticale based on the similarity of their ITS rDNA sequences with strains of C. corticale in a public collection. Furthermore, C. corticale was placed in the family Xylariaceae within the genus Biscogniauxia based on phylogenetic analysis of four genes (ITS nrDNA, actin, RPB2 and β‐tubulin). The closest relatives are B. bartholomei and Graphostroma platystoma.