Colletotrichum species cause severe anthracnose on Aucuba japonica in China

Abstract

Aucuba japonica is an evergreen ornamental shrub with significant ecological value and has been introduced and commonly cultivated in city parks. Colletotrichum species is recognized as one of the top ten most significant pathogenic fungi worldwide, which can cause damage to the crops, fruit trees and ornamental plants, resulting in reduced plant yield or quality. Recently, severe anthracnose was observed on the leaves of A. japonica in Linan District, Hangzhou, Zhejiang Province, China, and over 80 % of the leaves were infected. Colletotrichum-like fungal isolates were isolated from the affected area through moisturizing treatment. The selected isolates were identified as Colletotrichum boninense, C. fructicola and C. gloeosporioides based on morphological characteristics and multi-gene (ITS, ACT, CAL, GAPDH and TUB2) sequencing data. Pathogenicity test was conducted by inoculating 5 mm mycelial plugs onto healthy A. japonica detached leaves followed by re-isolation and re-identification procedures, which fulfill the Koch's postulates. This represents the first report that C. gloeosporioides also can cause anthracnose on A. japonica worldwide, highlighting the diversity of this pathogenic Colletotrichum species to A. japonica and contributes to the disease management.