• The Plant Pathology Journal
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• v.21 no.1
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• pp.27-32
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• 2005

Leaf anthracnose was observed on leaves of Japanese spindle tree in Seoul, Korea from autumn 2003 to spring 2004. The causal fungus was purely isolated from he leaf spot lesions and cultured on PDA. The colony on PDA was cream to orange but blackish in the center n old cultures. Conidia were formed in blackish orange asses and were cylindrical in shape, measured 13-17${\times}$5-7 ${\mu}$m in size. Blackish brown setae were often observed on PDA and ranged up to 100 ${\mu}$m in length. Based on morphological and ITS region sequence analyses, the fungal strain was identified as Colletotrichum boninense. Koch’s postulates were fulfilled by inoculating tree leaves with 1 ${\times}$ $106^6$ conidia per ml in a moist chamber. This is the first study on the pathogenicity, growth and phylogenetic characteristics of C. boninense causing leaf anthracnose on Japanese spindle tree in Korea.

• Research in Plant Disease
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• v.25 no.1
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• pp.33-37
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• 2019

From 2016 to 2018, approximately 15% of kohlrabi were observed displaying significant clubroot symptoms in farmer's fields in Jeju, Korea. The initial infection appeared as hypertrophy of root hairs, and as the disease progressed, galls formation occurred on the main roots, finally disease progress resulted in yellowing and wilting of leaves. Pathogenicity was proven by artificial inoculation of plants with resting spore suspension, fulfilling Koch's postulates. The resting spore is one-celled, spherical and subspherical, colorless, and $3-5{\mu}m$ in diameter. On the basis of the morphological characteristics and phylogenetic analyses of internal transcribed spacer rDNA, the causal agent was identified as Plasmodiophora brassicae. To our knowledge, this is the first report on the occurrence of P. brassicae on kohlrabi in Korea.

• Research in Plant Disease
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• v.21 no.1
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• pp.27-31
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• 2015

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, $4-11{\times}2.5-5{\mu}m$. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers (internal transcribed spacer rDNA and translation elongation factor $1{\alpha}$), 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.