• Title/Summary/Keyword: Sooty leaf blight

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Sooty Leaf Blight of Cymbidium spp. Caused by Pseudocercospora cymbidiicola (Pseudocercospora cymbidiicola에 의한 심비디움 검은잎마름병)

  • Han, Kyung-Sook;Park, Jong-Han;Lee, Jung-Sup;Cheong, Seung-Ryong
    • Research in Plant Disease
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    • v.13 no.2
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    • pp.126-129
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    • 2007
  • Sooty leaf blight disease of Cymbium spp. was observed on orchid fields located at Gyeonggi-do in 2005-2006. Symptoms of the disease appeared on leaves and leaf spots were circular to nearly-circular, these circular blemished were yellow, with greater amounts of brown to black flecks forming as the spots enlarge. Severely infected leaves were dry and defoliated. These symptoms were realized wrongly as symptoms by virus. But Pseudocercospora cymbidiicola were isolated from the diseased plants. Conidiophores were produced on the lesion surface of the leaf with the blemished areas andconidia formed dark brown, cylindrical and straight to slightly curved, 5-9 septate, $23.7-85.0\;{\times}\;2.0-3.4\;{\mu}m$. Mycelial growth was mostly slow on potato dextrose agar and the optimum temperature for growth was $25^{\circ}C$. We were identified as Pseudocercoepora cymbidiicola based on the morphological characteristics.

Sooty Leaf Blight of Dendrobium sp. Caused by Pseudocercospora dendrobii (Pseudocercospora dendrobii에 의한 덴드로비움 검은잎마름병)

  • Kwon, Jin-Hyeuk;Park, Chang-Seuk
    • The Korean Journal of Mycology
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    • v.30 no.2
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    • pp.173-175
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    • 2002
  • Sooty leaf blight was found on Dendrobium sp. in several farmers' fields located in Namji-eup, Changnyeong-gun, Gyeongnam province, Korea in 2001. Symptoms of the disease appeared on leaves. Sooty leaf spots were started with amphigenous, subeircular to irregular spots, with light grayish brown to black color with definite margin lines on the upper surface of leaves. Infected leaves became defoliated and whole plants eventually were died. The infection rates of the disease in the surveyed area reached up to 64.8%, in the early September. Conidiophores of the causal fungus were dark grayish brown in color, densely fasciculate, straight, curved to sinuous, branched, $5{\sim}10$ septate and $63{\sim}164{\times}3.2{\sim}4.9{\mu}m$ in size. Conidia were pale to olivaceous in color, obclavatecylindric, straight to slightly curved in shape, $1{\sim}5$ septate and $46{\sim}98{\times}3.2{\sim}3.9{\mu}m$ in size. The optimum temperature for mycelial growth of the fungus was $25^{\circ}C$. The fungus was identified as Pseudocercospora dendrobii on the basis of its mycological characteristics. This is the first report on sooty leaf light of Dendrobium sp. caused by Pseudocercospora dendrobii in Korea.