Sclerotium Rot of Cowpea (Vigna sinensis King) Caused by Sclerotium rolfsii

Jin-Hyeuk Kwon 1,*   Dong-Wan Kang1   Inyoung Han1   Yong-Jo Choi1   Sang-Dae Lee1   Daeyoung Son2   

Abstract

Sclerotium rot disease on cowpea (Vigna sinensis King) was observed in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services in September 2015. Lesions were covered by white mycelial mats, and numerous sclerotia were formed on the stem near the soil line. The sclerotia were globoid in shape, 1~3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on potato dextrose agar (PDA) was 30oC, with the hyphal width of 4~8 μm. For molecular identification, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was sequenced and analyzed. Based on the mycological characteristics, ITS rDNA sequence analysis, and pathogenicity test, this fungus was identified as Sclerotium rolfsii. This is the first report of sclerotium rot on cowpea caused by S. rolfsii in Korea.

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