Studies of Diaporthe species causing hazelnut canker disease in Beijing, China, with two new species described

Hazelnut (Corylus heterophylla) is a common tree species grown as a crop with high economic value. However, many diseases caused by Diaporthe greatly affect the health of hazelnuts. In this study, 35 isolates were obtained from hazelnuts with typical canker symptoms in Beijing, China. Four species of Diaporthe were identified through multilocus phylogenetic (ITS, cal, his3, tef1-alpha and tub2) and morphological analyses, including two new species (Diaporthe donglingensis and D. huairouensis) and two known species (D. corylicola and D. eres). D. donglingensis, D. eres and D. huairouensis were confirmed as the causal agents of canker of hazelnut by pathogenicity tests conducted on 2-year-old plants in the greenhouse. The current study contributes to the identification of species causing canker disease of hazelnut and provides useful information for effective disease management.