• Mycobiology
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• v.43 no.3
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• pp.343-346
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• 2015

In 2006~2010, leaf spot symptoms, that is, small, yellow spots that turned into dark brown-to-black lesions surrounded by a yellow halo, were observed on Cymbidium spp. in Gongju, Taean, and Gapyeong in Korea. A Fusarium species was continuously isolated from symptomatic leaves; in pathogenicity testing, isolates caused leaf spot symptoms consisting of sunken, dark brown lesions similar to the original ones. The causal pathogen was identified as Fusarium subglutinans based on morphological and translation elongation factor 1-alpha sequence analyses. This is the first report of F. subglutinans as the cause of leaf spot disease in Cymbidium spp. in Korea.

• Korean Journal of Medicinal Crop Science
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• v.17 no.6
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• pp.439-444
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• 2009

This study was to set the guidelines of soil chemical components in order to assure the safety and quality of the panax ginseng from physiological disorder. The disorder symptoms appeared on the leaf with yellow spot, atrophy, yellow-brown spot, also showed red skin and rough skin of the root. Occurrence type of physiological disorder in cultivated field divided into two types : type I 'such as, yellow spot' consist of single disorder symptom; type II 'such as, yellow spot and yellow-brown spot' consist of two or more different disorder symptoms. The individual contribution of soil properties to the occurrence type was as follows ; The yellow spot was affected by Na > $NO_3$-N > salinity (EC) in soil. The same results was observed in red skin. Atrophy was affected by $NO_3$-N > salinity (EC) > Ca > Mg. Rough skin was affected by $P_2O_5$>pH>Organic material > K. It showed positive associated to $P_2O_5$, pH and K, but negative associated to organic matter. Simultaneous occurrence of two different disorder, including cases which yellow spot and yellow-brown spot, those were affected by $NO_3$-N > salinity (EC) > Na > Mg. In the case of atrophy plus yellow-brown spot, those also were affected by in the order : $NO_3$-N > salinity (EC) > Ca > Mg > Na. Red-rough skin was affected in the order : salinity (EC) > $NO_3$-N > K > Na. Soil chemical components appear to be related to occurrence of physiological disorder, particularly in salinity (EC) and $NO_3$-N. The salinity (EC) and $NO_3$-N were negative related to plant growth. In addition, exchangeable cation capacity play critical roles in attributing to complex occurrence of physiological disorder.

• Mycobiology
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• v.51 no.6
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• pp.393-400
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• 2023

During a disease survey in October 2019, leaf spot symptoms with a yellow halo were observed on Korean angelica (Anglica gigas) plants grown in fields in Pyeongchang, Gangwon Province, Korea. Incidence of diseased leaves of the plants in the investigated fields ranged from 10% to 60%. Morphological and cultural characteristics of two single-spore isolates from the leaf lesions indicated that they belonged to the genus Didymella. Molecular phylogenetic analyses using combined sequences of LSU, ITS, TUB2, and RPB2 regions showed distinct clustering of the isolates from other Didymella species. In addition, the morphological and cultural characteristics of the isolates were somewhat different from those of closely related Didymella spp. Therefore, the novelty of the isolates was proved based on the investigations. Pathogenicity of the novel Didymella species isolates was confirmed on leaves of Korean angelica plants via artificial inoculation. This study reveals that Didymella gigantis sp. nov. causes leaf spot in Korean angelica.

• Research in Plant Disease
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• v.9 no.3
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• pp.149-152
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• 2003

Black leaf spot disease occurred on Dendrobium phalaenopsis grown in farmer's fields located in Bonggangmyon, Gwangyang-eup, Jeonnam, Korea. Black small spots occurred on leaves at initial stage of infection and the infected leaves turned yellow from the tip. The yellow leaves were falled, resulting in stem blighting or eventual death of the entire plant. White mycelial colony of the causal fungus grown on potato dextrose agarturned dark violet later and optimum temperature for the mycelial growth was $25^{\circ}C$. The causal fungus isolated from the black leaf spot on D. phalaenopsis was identified as Fusarium moniliforme based on the mycological characteristics and pathogenicity. The fungus also caused same symptoms on leaves of Phalaenopsis sp. and Cymbidium sp. as well sa D. phalaenopsis by wound inoculation. This is the first report on black leaf spot of D. phalaenopsis caused by F.moniliforme in Korea.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.664-667
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• 1998

Leaf spot of Cymbidium hybrida caused by Fusarium sp. was observed at major cultivating areas including Seosan and Cheonan of Korea from 1996 to 1998. The major symptoms of the disease were small brown to black spots, 1∼2 mm I diameter, with yellow halo. Based on the mycological characteristics, Fusarium sp. isolated from the lesions was identified as Fusarium proliferatum. Macroconidia were slender, falcate to almost straight, usually 3 to 5 septate and thin walled. Microconidia were formed in chains from polyphialides, clavate or oval, usually 1-celled with flattened base. Chlamydospores were absent. The fungus showed pathogenicity to Cymbidium hybrida.

• Research in Plant Disease
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• v.10 no.2
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• pp.126-129
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• 2004

In July of 2002, leaf spot disease was found on kudzu (Pueraria lobata) leaves in Jeonbuk province. A small leaf spot was appeared on leaves as a typical symptom and the spot was then surrounded by chlorotic halo. The lesions were expended and coalesced and the infected leaves became yellow leaf and later fall out. A causal fungal pathogen was isolated and the colony of the pathogen was light gray green to dark green on PDA. The pathogen produced mostly the single conidium but rarely long chain of 3 to 8 conidia. The conidia were dark brown in color, long ellipsoid or oval and 20-60 ${\times}$ 10-25 ${\mu}{\textrm}{m}$ in size. Their septa were 4-8 transverse and 1-2 longitudinal or oblique. The pathogen was, therefore, identified as Alternaria tenuissima based on cultural and morphological characteristics. This is the first report on the leaf spot of kudzu caused by A. tenuissima in Korea.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.153-158
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• 2001

Leaf spots in Saintpaulia leaves are caused by temperature drop shock (TDS). This TDS-mediated leaf injury has not been reported in other plants besides Saintpaulia. To investigate how many and what kinds of plants are susceptible to temperature drop shock, Gesneriaceae and Acanthaceae plants were treated with TDS (from $30^{\circ}C$ to $15^{\circ}C$ or $5^{\circ}C$). Yellow or brown spots were found in 26 species or cultivars of 10 genuses of Gesneriaceae plants and in 8 species or cultivars of 7 genuses of Acanthaceae plants. Morphologically and anatomically no similarity was observed among the plants susceptible to TDS. Some plants have very thin and hard leaves, whereas other plants have thick and soft leaves. In spite of this non-similarity, the injury was restricted only to palisade cells as those of Saintpaulia leaves. Also the rapid and irreversible reduction of chlorophyll fluorescence was observed soon after TDS treatment in those plants. These results indicate that leaf injury induced by TDS is a more widespread leaf injury than has previously been thought.

• Research in Plant Disease
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• v.24 no.3
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• pp.175-181
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• 2018

Incidence rates of bacterial canker, bacterial leaf spot and postharvest fruit rot on the Korean yellow-fleshed kiwifruit cv. Haegeum were compared with those on the most popular green-fleshed kiwifruit cv. Hayward grown in several naturally infected kiwifruit orchards in 2013 and 2014. The percentages of diseased leaves caused by bacterial canker were 18.5% and 17.3% on Hayward in 2013 and 2014, but those on Haegeum were 1.2% and 0%, respectively. The percentages of diseased leaves caused by bacterial leaf spot on Hayward were 63.5% and 16.2% in 2013 and 2014, respectively, but no bacterial leaf spots were observed on Haegeum in both years. The average percentages of diseased fruits caused by postharvest fruit rot were 24.2% and 20.5% on Hayward in 2013 and 2014, while 6.3% and 4.4% and Haegeum, respectively. Botryosphaeria dothidea was turned out to be the major pathogen of postharvest fruit rot on both cultivars.

• Mycobiology
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• v.46 no.2
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• pp.168-171
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• 2018

In 2016, a severe leaf spot disease was found on Iris ensata Thumb. in Nanjing, China. The symptom was elliptical, fusiform, or irregularly necrotic lesion surrounded by a yellow halo, from which a small-spored Alternaria species was isolated. The fungus was identified as Alternaria iridiaustralis based on morphological characteristics. The pathogenicity tests revealed that the fungus was the causal pathogen of the disease. Phylogenic analyses using sequences of ITS, gpd, endoPG, and RPB2 genes confirmed the morphological identification. This study is the first report of A. iridiaustralis causing leaf spots on I. ensata in China.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.612-615
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• 2009

Lipoxygenase and Kunitz trypsin inhibitor protein are the main antinutritional factor in mature soybean seed. A new soybean cultivar, "Gaechuck#2" with yellow seed coat, lipoxygenase2,3-free and Kunitz trypsin inhibitor protein-free was developed. It was selected from the population derived from the cross between "Jinpumkong2ho" and C242. Plants of "Gaechuck#2" have determinate growth habit with purple flowers, tawny pubescence, yellow seed coat, yellow hilum, oval leaflet shape and brown pods at maturity. Seed protein and oil content on a dry weight basis were 40.7% and 18.7%, respectively. It has shown a resistant reaction to soybean necrosis, soybean mosaic virus, Cercospora leaf spot and blight, black root rot, pod and stem blight, and soybean pod borer. Gaechuck#2 matured in 4 October with plant height of 54cm and a 100-seed weight of 24.4g. Average Yield of Gaechuck#2 was 230 - 250 kg/10a in 2005 - 2007.