Two new species of Colletotrichum (Glomerellaceae, Glomerellales) causing walnut anthracnose in Beijing

Abstract

Colletotrichumspecies are plant pathogens, saprobes and endophytes on various plant hosts. It is regarded as one of the 10 most important genera of plant pathogens in the world. Walnut anthracnose is one of the most severe diseases affecting walnut productivity and quality in China. In this study, 162 isolates were obtained from 30 fruits and 65 leaf samples of walnut collected in Beijing, China. Based on morphological characteristics and DNA sequence analyses of the concatenated loci, namely internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), chitin synthase 1 (CHS-1) and beta-tubulin (TUB2), these isolates were identified as two novel species ofColletotrichum, i.e.C. juglandicolaandC. peakense. Koch’s postulates indicated that bothC. juglandicolaandC. peakensecould cause anthracnose in walnut.