Invasive Species Compendium

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Abstract

First report of Corynespora cassiicola causing leaf spot on Akebia trifoliate.

Abstract

During the summer of 2012, a leaf spot disease was detected on A. trifoliata grown in Nanning, Guangxi, China. The disease occurred and spread rapidly in July under conditions of high temperature and high humidity. The symptoms appeared in three sites, and disease incidence was more than 80%. Initial symptoms consisted of small (less than 5 mm in diameter), circular, purple-brown leaf spots. Spots later enlarged and became elliptical, circular, or irregular with grey-white centres and dark brown rims. The centres were slightly concave. The spots could coalesce with each other, resulting in leaf desiccation and wilting. A fungal isolate was obtained from symptomatic leaf tissue. The morphological characteristics of the isolate were similar to the descriptions of C. cassiicola. The genomic DNA of the isolate was extracted and used for PCR amplification of rDNA-ITS (internal transcribed spacer) sequence with primers ITS1 and ITS4. The PCR products were purified and sequenced. The sequence (GenBank Accession No. KC977496) was used in BLAST searches to interrogate GenBank for sequence similarity. High sequence similarity of 100% was obtained with several C. cassiicola strains. This is thought to be the first report of C. cassiicola on Akebia species worldwide.