Diaporthe species causing shoot dieback of Acer (maple) in Henan Province, China

Maple is an important ornamental plant in China. With the increasing use of maple trees in landscaping, a symptom of shoot dieback has been observed in Henan province, China. In this study, 28 Diaporthe isolates were obtained from symptomatic shoots of maple trees between 2020 and 2023. Phylogenetic analyses based on five loci (ITS, TEF, CAL, HIS and TUB) coupled with morphology of 12 representative isolates identified three known species (D. eres, D. pescicola and D. spinosa) and one new species, namely D. pseudoacerina sp. nov. Koch's postulates confirmed that all these species were pathogenic. Additionally, D. pseudoacerina was able to infect China wingnut (Pterocarya stenoptera), pear (Pyrus sp.), and black locust (Robinia pseudoacacia). This study marks the first report of Diaporthe spinosa and D. pescicola pathogens infecting maple trees. These findings enhance the existing knowledge of the taxonomy and host diversity of Diaporthe species as, while also providing valuable information for managing of maple shoot dieback in Henan Province, China.