First Report of Fusarium Wilt Caused by Fusarium oxysporum on Kohlrabi in Korea

• Main Authors: In-Young Choi, Ju Kim, Ho-Jong Ju, Ji-Hyun Park, Hyeon-Dong Shin
• Format: Article
• Language: English
• Published: Hanrimwon Publishing Company 2015-03-01
• Series: Research in Plant Disease
• Subjects: Brassica oleracea var. gongylodes; Fusarium oxysporum; Fusarium wilt; Kohlrabi
• Online Access: http://www.online-rpd.org/journal/view.html?uid=1433&pn=lastest&vmd=Full

In April 2014, Fusarium wilt was found on kohlrabi seedlings in Iksan, Korea. Symptoms included wilting of foliage, drying and withering of older leaves, and stunting of the plants. The infected plants eventually died during growth. Colonies on potato dextrose agar were pinkish white, and felted with cottony and aerial mycelium. Macroconidia were falcate to almost straight, thin walled and usually 3-septate. Microconidia were usually formed abundantly in false-heads on short monophialides on the hyphae and were hyaline, smooth, oval to ellipsoidal, aseptate or medianly 1-septate, very occasionally 2-septate, slightly constricted at the septa, 4-11 × 2.5-5 mm. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers (internal transcribed spacer rDNA and translation elongation factor 1a), the fungus was identified as Fusarium oxysporum. Pathogenicity of a representative isolate was proved by artificial inoculation, fulfilling Koch’s postulates. To our knowledge, this is the first report on the occurrence of Fusarium oxysporum on kohlrabi in Korea.