English
First Report of Anthracnose Caused by Colletotrichum spp. on Osmanthus fragrans var. aurantiacus
Seungmin Lee1, Sun Choi1, and Gyoung Hee Kim1,2*
1Department of Agricultural Life Science, School of Green Smart Farm, Sunchon National University, Suncheon 57922, Korea
2Department of Plant Medicine, College of Life Science and Natural Resources, Sunchon National University, Suncheon 57922, Korea
*Email: ghkim@scnu.ac.kr
Anthracnose symptoms were observed on Osmanthus fragrans var. aurantiacus, an ornamental plant widely cultivated in Korea, in January 2026 in Goheung, Jeonnam Province. Approximately 20–30% of leaves showed anthracnose symptoms characterized by irregular necrotic lesions developing along the leaf margins. The lesions appeared pale gray and were surrounded by a distinct yellow halo. As the disease progressed, lesions expanded along the leaf margins, resulting in partial necrosis of leaf tissues. Fungal isolates obtained from symptomatic tissues were cultured on potato dextrose agar. Based on morphological characteristics and multilocus phylogenetic analyses of ITS, ACT, GAPDH, TUB2, CHS, HIS3, CAL, and ApMat gene sequences, the isolates were identified as Colletotrichum gloeosporioides, C. siamense, and C. fioriniae. Maximum likelihood phylogenetic analysis of concatenated gene sequences placed representative isolates within the corresponding species clades. Pathogenicity tests were conducted by spray-inoculating a conidial suspension (5 × 10⁶ conidia/mL) onto leaves of O. fragrans var. aurantiacus. Typical anthracnose symptoms were reproduced on inoculated leaves, whereas control leaves remained symptomless. The pathogens were successfully re-isolated from symptomatic tissues, thereby fulfilling Koch’s postulates. To our knowledge, this is the first report of anthracnose caused by C. gloeosporioides, C. siamense, and C. fioriniae on O. fragrans var. aurantiacus worldwide.
