• The Plant Pathology Journal
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• 제39권2호
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• pp.181-190
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• 2023

The fungal pathogen Pseudocercospora fuligena, known to affect tomatoes in the tropics and subtropics, has been reported from temperate climates including the United States and Turkey in recent years. In this study, an isolate from fresh tomatoes and the disease it causes were characterized and infection mechanisms investigated. Macroscopically, both sides of tomato leaves show indistinct effuse patches but prolific production of fuliginous lesions is conspicuous on the abaxial side first but also on the adaxial side later on as infection progressed. Microscopically, fascicles of conidiophores (11-128 ㎛ × 3.5-9 ㎛) arising from stromata and conidia with up to 12 septations were observed. Molecular characterization of the isolate revealed high homology (99.8%) to other P. fuligena isolated from tomatoes in Turkey. Out of the 10 media tested, P. fuligena grew significantly well and sporulated better on unsealed tomato oatmeal agar and carrot leaf decoction agar, both supplemented with CaCO₃. Direct transfer of conidia from profusely sporulating lesions was the easiest and quickest method of isolation for in-vitro studies. Light and scanning electron microscopy on cleared and intact tomato leaves further confirmed stomatal penetration and egress as well as prevalence of primary and secondary infection hyphae. In situ, blocked stomatal aperture areas of 154, 401, and 2,043 ㎛² were recorded at 7, 12, and 17 days after inoculation, respectively. With the recent expanded horizon of the pathosystem and its consequential impact, such studies will be useful for a proper diagnosis, identification and management of the disease on tomato worldwide.

• The Korean Journal of Mycology
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• 제30권2호
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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.

• Korean Journal Plant Pathology
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• 제14권5호
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• pp.473-483
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• 1998

This paper is the sixth report about the fungal diseases of economic resource plants observed newly in Korea. It contains short descriptions on symptoms, occurrence conditions, pathogens, and some phytopathological notes for each of 10 fungal plant diseases. They are identified as circular leaf spot of Ligustrum ovalifolium by Cercospora adusta, leaf spot of Viola spp. by c. violae, leaf spot of Trifolium repens by C. zebrina, hypophyllous leaf sot of Angelica gigas by Passalora depressa, brown leaf spot of Euonymus japonicus by Pseudocercospora destructiva, brown leaf spot of Lonicera japonica by P. lonicericola, brown leaf spot of Parthenocissus tricuspidata by P. vitis, black spot of Echinops latifolius by Ramularia cynarae, leaf spot of Petasites japonicus by R. major, and leaf spot of Plantagoasiactica by R. plantaginis, respectively.

• Research in Plant Disease
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• 제28권2호
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• pp.57-60
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• 2022

Leaves of Chionanthus retusus were found to be damaged by leaf spot disease associated with a fungus in Iksan, Korea. Leaf spots were angular to irregular, vein-limited, scattered, 1-8 mm diameter, brownish-gray to dark brown when dry, with heavy fructification. The pathogen causes premature defoliation of C. retusus plant and was identified as Pseudocercospora chionanthi-retusi based on morphological and molecular-phylogenetic analyses. The phylogenetic tree was constructed using multi-locus DNA sequence data of partial actin (actA), partial translation elongation factor 1-alfa (tef1), partial DNA-directed RNA polymerase II second largest subunit (rpb2) genes, and internal transcribed spacer regions. Current study provides detail morphological description of P. chionanthi-retusi on C. retusus in Korea, with supports of phylogenetic analysis and pathogenicity test.

• The Korean Journal of Mycology
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• 제51권2호
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• pp.147-153
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• 2023

Dark brown leaf molds growing in a vein-limited pattern have been continuously observed on the lower leaf surface of Fatoua villosa in Korea. Fifteen samples deposited in the Korea University herbarium were examined for fungal morphological characterization. Two monoconidial isolates were obtained in 2022, and molecular analysis was performed based on a combined multigene dataset of the internal transcribed spacer (ITS) region and partial actin (actA), translation elongation factor 1-alpha (tef1), and DNA-directed RNA polymerase II second-largest subunit (rpb2). Based on morphological features and molecular phylogenetic analysis, the fungus Pseudocercospora fatouae was identified. To the best of our knowledge, it is the first study reporting the presence of P. fatouae on F. villosa in Korea.

• The Korean Journal of Mycology
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• 제50권2호
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• pp.131-136
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• 2022

Cornus officinalis plants that grow in several locations in Korea have been found to be infected with leaf spot disease. Symptoms include necrotic lesions, which are angular, irregularly shaped, vein-limited, and dark brown, on both sides of the leaves. The causal agent of the disease was identified to be Pseudocercospora cornicola based on the morphological characteristics of the fungus and molecular phylogenetic analysis of the obtained multi-locus DNA sequence data. This is the first report investigating P. cornicola found on C. officinalis in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 한국식물병리학회 2005년도 추계 학술발표회
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• pp.49-50
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• 2005

• Research in Plant Disease
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• 제10권4호
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• pp.341-344
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• 2004

Grapevine leaf spot caused by Pseudocercospora vitis also called leaf Isariopsis spot which is one of the most important disease in Korea. Spots on the leaves are irregular to angular. They are brown, measure 2${\sim}$20 mm in diameter. Campbell Early, the major grape cultivar in Korea, is very susceptible to this disease. Leaf spot of grape is outbreak about 95% in ratio of diseased leaves according to the areas and management state of orchards in Korea. The diseased grapevines have some difficulty in raise of the trees by early defoliation and decrease the quality of fruits by disadvantage of assimilation products accumulation. Severe outbreak of the grapevine leaf spot is one of the factors that decrease of sugar content of the fruits about 20%. The strong negative correlation was observed between disease increase of grapevine and decrease of sugar content of the fruits. The correlation equation between relative sugar content of fruits and accumulated percentage of diseased leaves was Y = 0.0009$X^2$ - 0.3717X + 116.45($r^2$= 0.98).

• Research in Plant Disease
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• 제12권1호
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• pp.10-14
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• 2006

This study was carried out to know damages of the grapevine trees by the disease to the leaf spot from 2000 to 2003. The isolates collected from different varieties and locations were identified as Pseudocercospora vitis ($(L\acute{e}v)$.) Speg. based on the morphological and cultural characteristics. According to the in vitro test, the range of temperatures for the mycerial growth and the conidical germination of the fungus were from $10^{\circ}C\;to\;35^{\circ}C$ and optimum temperature was $25^{\circ}C$. There were remarkably different features between a low infection trees group and high infection trees group in terms of number of leaves per fruit branch, length and diameter of internode and leaf area.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 한국식물병리학회 2005년도 한국식물병리학회 임시총회 및 춘계학술발표회
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• pp.40.2-41
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• 2005