First report of Cryphonectria carpinicola on Carpinus betulus in Serbia

When monitoring the health status of various woody host plants in urban areas in Serbia, symptoms indicative of Cryphonectria-like infection were recorded on European hornbeam (Carpinus betulus) trees in the natural monument ‘Arboretum of the Faculty of Forestry in Belgrade’. One tree was affected by crown dieback while another one showed dieback of branches. Bark lesions were found on stems which contained numerous stromata with fruiting bodies and orange tendrils. Conidiomata were recorded solely in the infected tissue, producing hyaline, aseptate and bacilloid-shaped conidia with dimensions of 3.4 ± 0.46 × 1.2 ± 0.12 μm. In the isolation tests, all plated bark pieces were positive, and 25 isolates were obtained. Colonies on different agar media were white in the beginning, turning into orange-red colour during ageing. Optimum temperature for growth was 25°C and no growth was recorded at 30°C. A GenBank blast search and a phylogenetic analysis of ITS rDNA sequences of five representative isolates revealed their identity as Cryphonectria carpinicola. To our knowledge, this is the first report of C. carpinicola on hornbeam trees in Serbia, and implications of this finding are discussed.