The occurrence of Sclerotium rot on white clover (Trifolium repens L.) caused by Sclerotium rolfsii in Korea

We observed an occurrence of sclerotium rot on white clover (Trifolium repens L.) grown as a green manure in sweet persimmon orchards of Jinju, Korea. The typical symptoms included gradual blighting, wilting, and rotting; and severely infected plants eventually died. Furthermore, mycelial mats spread over the infected white clover petioles and sclerotia formed near the soil surface. Sclerotia were globoid, 1-3 mm, and white to brown. The optimum temperature for growth on potato dextrose agar was 30 C. White mycelium formed a typical clamp connection. Based on the morphological characteristics, internal transcribed spacer (ITS) sequence analysis, and pathogenicity tests, the causal agent was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot from S. rolfsii on white clover in Korea. © 2013 Australasian Plant Pathology Society Inc.