Corynespora leaf spot of Ligustrum quihoui caused by Corynespora cassiicola in China

摘要

Ligustrum quihoui is a perennial shrub that has been cultivated in China as a landscape plant. In November 2020, leaf spots on L. quihoui were observed in several residential areas in the east of Anqing city. Symptoms first appeared as small dark brown dots on the leaf surface which then became larger, forming necrotic lesions and resulting in intense defoliation. To identify the pathogen, infected leaves were collected and cultured on potato dextrose agar (PDA). Three cultures were isolated from the diseased leaves, which grew to form olive green colonies after 5 days of incubation on PDA. Based on colony characteristics, morphology phylogenetic analysis of ribosome transcriptional spacers (rDNA-ITS), and pathogenicity tests, the causal agent of leaf spot on L. quihoui was identified as Corynespora cassiicola. This is the first report to show that C. cassiicola can cause leaf spot on L. quihoui.