Morphology, phylogeny and pathogenicity analyses on Cytospora leucostoma, Phaeobotryon rhois and Diplodia gallae and two new species (C. huairouensis and C. prunina) from apricots in China identified the first two as pathogens.

Abstract

Apricot (Prunus armeniaca) is an economically important fruit tree in Beijing, China. However, canker diseases have become one of the main threats to apricot production. In the present study, a field survey was conducted in apricot orchards in Beijing and the disease incidence of apricots was surveyed (75.7%). Thirty fungal strains were isolated from branches of apricots. Five species were identified through multilocus phylogenetic (rDNA internal transcribed spacer [ITS], large subunit [LSU] and tef1-a for Botryosphaeriales; ITS, act, rpb2, tef1-a and tub2 for Cytospora) and morphological analyses, including two new species (Cytospora huairouensis and C. prunina) and three known species (C. leucostoma, Diplodia gallae and Phaeobotryon rhois). C. leucostoma and P. rhois were identified as the causal agents of canker of apricot by pathogenicity tests conducted on 3-year-old plants in the greenhouse. The current study contributed to a theoretical basis for predicting the potential risk of apricot canker in Beijing, China.