First repot of leaf spot disease caused by Cladosporium allicinum on barley in Korea

Barley (Hordeum vulgare) is an important cereal crop in Korea, and its cultivation faces increasing risks of fungal diseases under changing climate conditions. In April 2021, barley (Hordeum vulgare) plants in Boseong-gun and Jangheung-gun, Korea, exhibited leaf spot symptoms with brown elliptical lesions and chlorosis. Fungal isolates (SYP-572, SYP-573, SYP-581) were obtained from symptomatic leaves and identified as Cladosporium allicinum based on morphology and multilocus phylogeny of ITS, tef1, and act genes. Colonies were dark brown with velvety texture, and conidia formed in long chains, ellipsoid to obclavate. Pathogenicity of isolate SYP-572 was confirmed on barley cv. Keunalbori-1ho, fulfilling Koch’s postulates. This study represents the first report of leaf spot caused by C. allicinum on barley in Korea and provides a basis for future disease management. [This paper was supported by Sunchon National University Glocal University Project Fund in 2025.]