Occurrence of southern blight disease on Cleyera japonica by Sclerotium rolfsii Saccardo

Blight-like symptoms on Cleyera japonica Thunb. were first found on plants growing on the shrine in Omura, Nagasaki, Japan on June 19, 2009. White mycelia and brown, spherical, rapeseed-sized sclerotia were observed on the diseased plants. A fungus similar to Sclerotium rolfsii Saccardo was isolated from infected plants. The optimum growth temperature of these isolates, on potato dextrose agar, was 25℃for mycelial growth and 30℃for sclerotium formation. The mycelial tufts were white to grayish brown, and the main hyphal width ranged from 4.5-7.8μm（avg. = 6.6μm）with clamp connections. These mycological characters are identical to those of S. rolfsii reported in other plants. The isolates were found to be pathogenic to C. japonica in artificial inoculation test, and could be re-isolated from infected tissue. It is proposed that the disease should be referred to as southern blight of C. japonica caused by S. rolfsii.