Occurrence of Sclerotium Rot of Cucumber Caused by Sclerotium rolfsii

Research in Plant Disease 2013;19(3):229-232.
Published online September 30, 2013.

Sclerotium rolfsii에 의한 오이 흰비단병 발생

권진혁 ( Jin Hyeuk Kwon ) , 이상대 ( Sang Dae Lee ) , 최옥연 ( Ok Ryun Choi ) , 신순선 ( Shun Shan Shen ) , 심홍식 ( Hong Sik Shim )

Occurrence of Sclerotium Rot of Cucumber Caused by Sclerotium rolfsii

Jin-Hyeuk Kwon1*, Sang-Dae Lee1, Okryun Choi2, Shun-Shan Shen3 and Hong-Sik Shim4

¹Gyeongsangnam-do Agricultural Research and Extension Services, Jinju 660-360, Korea
²Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju 660-701, Korea
³College of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China
⁴National Academy of Agricultural Science, RDA, Suwon 441-707, Korea

Received: July 16, 2013 Revised: September 13, 2013 Accepted: September 14, 2013

Abstract

Sclerotium rot of cucumber (Cucumis sativus L.) occurred at the experimental field of Gyeongsangnam-do Agricultural Research and Extension Services in July 2012. The typical symptoms included wilt, rot, and water-soaking on stems and fruits and severely infected plants eventually died. White mycelial mats spread over lesions, and then sclerotia were formed on fruit and near soil line. The sclerotia were globoid in shape, white to brown in color and 1?3 mm in size and the hyphal width was 4?8 μm. The optimum temperature for mycelial growth and sclerotia formation on PDA was 30oC. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. For further identification, the complete internal transcribed spacer (ITS) rDNA region was amplified and sequenced. On the basis of mycological characteristics, ITS rDNA region comparison, and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot on cucumber caused by S. rolfsii in Korea.

Key Words: Cucumber, Cucumis sativus L., Sclerotium rolfsii, Sclerotium rot