• Korean Journal Plant Pathology
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• v.1 no.1
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• pp.56-60
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• 1985

The present researches were carried out to examine the favorable nutritional conditions for mycelial growth of Cercospora kikuchii, and inhibition of bacterial growth by the fungus at various cultural conditions. As the nitrogen source, the fungus grew better on yeast-extract than the other sources of nitrogen tested. Sucrose, glucose, maltose and fructose were good sources of carbon for mycelial growth of the fungus. Two isolates of C. kikuchii, wild types A and D, inhibited the growth of bacteria on the medium containing yeast-extract or peptone as the nitrogen source, and sucrose, glucose, maltose or fructose as the carbon source, at pH 5.0. However, the albino mutant showed very little inhibitory effect under the same conditions.

• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.138-146
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• 1999

This paper is the seventh contribution towards taxonomic studies on Cercospora and allied genera, and contains ten species of Korean cercosporoid fungi; viz., Cercospora arcti-ambrosiae, C. cichorii, C. kikuchii, C. subhyalina, Neoramularia koreana, Pseudocercospora ligustri, P. oenotherae, P. rubi, P. zelkowae, and Ramularia archangelicae. Morphological characteristics of taxonomic value are described and illustrated for these species to contribute towards a mycological monograph of Korean cercosporoid fungi.

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.263-268
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• 1983

In a survey of seed-borne mycofloras of Glycine max, 21 species have been isolated. Alternaria tenuis, Aspergillus spp., Cercospora kikuchii, Penicillium spp. and Fusarium spp. were the predominant fungi. C. kikuchii was isolated more often from purple stained seed than from unstained seed, and Fusarium spp., Phomopsis sp., Aspergillus spp. and Penicillium spp. were isolated less frequently in stained than unstained seeds. In inoculation experiments, C. kikuchii, Colletotrichum dematitum, Phomopsis sp. produced mild to severe symptoms on leaves when suspension of their conidia and mycelia were sprayed on to plants. In soil inoculation experiments, Fusarium oxysporum, F. moniliforme and F. semitectum showed pathogenicity causing seed rot and seedling blight.

• The Korean Journal of Mycology
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• v.12 no.1
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• pp.27-33
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• 1984

Alternaria tenuis, Arthrobotrytis sp., Aspergillus spp., Cephalosporium sp., Cladosporium sp., Cylindrocarpon sp., Fusarium equiseti, F. moniliforme, F. semitectum, F. solani, Penicillium spp., Rhizopus sp. were saprophytic fungi and Cercospora kikuchii, Colletotrichum truncatum, Diaporthe phaseolorum var. sojae and Fusarium oxysporum were pathogenic fungi detected from 14 seed samples of soybean. Initial symptoms caused by C. kikuchii, C. truncatum, D. phaseolorum sojae and F. oxysporum on seedlings from naturally infected seed by the test tube agar method have been described and discussed. Soybean seeds infected with C. truncatum, D. phaseolorum sojae and F. oxysporum reduced germination of seeds and have influenced on the growth of soybean seedling caused by C. kikuchii. Surface-sterilized soybean seedlings became diseased in the test tube agar artificially inoculated with C. kikuchii, C. truncatum and D. phaseolorum sojae isolated from naturally infected soybean seeds. F. oxysporum showed very weak pathogenicity. Seed disinfectants of Benlate-T, Homai, Tecto and Sisthane have effective to C. kikuchii, C. truncatum, D. phaseolorum sojae and F. oxysporum. Arasan, Captan, Busan-30 and Mercron were inferior to C. kikuchii but effective against others. Seed disinfectants treated in this experiment have increased seed germination campared with non-treatment.

• The Plant Pathology Journal
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• v.18 no.4
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• pp.216-220
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• 2002

Seed decay of soybean caused by Diaporthe phaseolorum, Colletotrichum truncatum and Cercospora kikuchii is a serious disease when soybean is harvested under warm and wet weather conditions. Benomyl has been used for controlling the disease, however, benomyl application may be limited due to common occurrence of resistance. The efficacy of 21 fungicides against the pathogens was evaluated in vitro. Among the fungicides tested, benomyl, carbendazim, fluazinam, iprodione+propineb, thiophanate-methyl, and triflumizole were found effective and were evaluated for their ability to control the seed pathogens. Fluazinam completely inhibited mycelial growth at a concentration of 100 $\mu\textrm{g}$/$\textrm{m}{\ell}$ for D. phaseolorum; and at a concentration of 500 $\mu\textrm{g}$/$\textrm{m}{\ell}$ for C. truncatum and C. kikuchii. $EC_90$ values of fluazinam were similar to that of benomyl. Because fluazinam, iprodione+propineb, and triflumizole were found effective against the seed pathogens, these were subjected for field-testing. Suppression of pod and seed infection by fluazinam and iprodione+propineb was as high as that of benomyl without any reduction in agronomic characters of soybean. This study shows that fluazinam and iprodione+propineb may be used in combination with benomyl to control seed pathogens, manage resistance, and ensure production of high quality soybean seeds.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.23-26
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• 1982

The present study was carried out to investigate the change of peroxidase activity of soybean seed infected with Cerrospora kikurhii. The protein content, polyphenol oxidase activity and peroxidase isozyme pattern in health and infected soybean seed were also compared. 1. The peroxidase activity was substantially higher in the infected soybean seeds than that in the healthy seeds either cracked or not. No significant differences in protein content were recognized among the seeds tested. 2. No significant differences in peroxidase activities and protein contents were notified between healthy and infected seeds from the measurements on each parts of dissected seeds, cotyledon and seedcoat, however the peroxidase activity in the seed coat of the stained seed was 2.5 times to healthy seed. 3. The activities of polyphenel oxidase were undectable in both healthy and diseased seeds. 4. The electrophoretic Patterns of the Peroridase isozyme were the same between healthy and in footed seed. 5. Therefore, the increase of peroxidase activity in infected soybean seedcoat was mainly due to the biochemical reaction against the pathogen.

• Korean journal of applied entomology
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• v.20 no.3 s.48
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• pp.131-134
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• 1981

Native soybean collections were evaluated to search a resistant gene source to purple blotch caused by Cercospora kikuchii. Among 467 native lines, about $28.9\%$ of the lines was less than $0.1\%$ and $13.4\%$ was over $2\%$ in natural infection of purple blotch. Natural infection seemed to be significantly associated with weather conditions at the early podding stage. A significant correlation between natural infection and purple discoloration by seed inoculation was observed and this method seemed to be effective as a preliminary screening technique for resistance to purple blotch. Most of the late maturing native soybeans showed susceptible reaction by the seed inoculation contrary to low infection under natural conditions, indicating that the low natural infection might be due to disease escaping by the late maturing instead of their genetic resistance.

• Research in Plant Disease
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• v.7 no.2
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• pp.107-111
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• 2001

Deterioration of pod and seed quality by pod and stem blight and purple blotch is a serious problem in the production of vegetable soybean. Major inoculum sources for the causal pathogens, Phomopsis spp. and Cercospora kikuchii, are soybean straw and debris. Phomopsis spp. have been known to be either limited for hyphal growth or latent in immature soybean tissues. In this experiment, cultural practices using these ecological traits of the pathogens were applied as a control measure. In plastic mulching, seed infection was remark ably reduced by drip irrigation as compared to overhead sprinkling, but not reduced in no mulching cultivation. Control value of plastic mulching was 28.0% for pod and stem blight and 29.3% for purple blotch, which was lower than that of benomyl application. By the first week in June, 78% of overwintered soybean straw examined contained matured alpha spores in pycnidia, acting as primary inoculum. Secondary inoculum of phomopsix spp. was observed abundantly throughout from mid June to September on fallen cotyledons from current crops and subsequently was found on petiole debris. Consequently, both plastic mulching and drip irrigation were effective to some extent for controlling pod and stem blight and purple blotch without significant reduction in soybean yield, and the cultural practices in combination with field sanitation resulted in removing more the secondary inoculum.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.11-15
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• 1977

Natural infection of purple stain seemed to be higher in early maturing lines comparing to late maturing group. It was positively correlated with length of the period from flowering to maturity and significantly associated with weather conditions during the maturing period.

• The Plant Pathology Journal
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• v.39 no.5
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• pp.513-521
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• 2023

Seed-borne diseases reduce not only the seed germination and seedling growth but also seed quality, resulting in the significant yield loss in crop production. Plant seed harbors diverse microbes termed endophytes other than pathogens inside it. However, their roles and application to agricultures were rarely understood and explored to date. Recently, we had isolated from soybean seeds culturable endophytes exhibiting in-vitro antagonistic activities against common bacterial and fungal seed-borne pathogens. In this study, we evaluated effects of seed treatment with endophytes on plant growth and protection against the common seed-borne pathogens: four fungal pathogens (Cercospora sojina, C. kikuchii, Septoria glycines, Diaporthe eres) and two bacterial pathogens (Xanthomonas axonopodis pv. glycines, Pseudomonas syringae pv. tabaci). Our experiments showed that treatment of soybean seeds with seed endophytes clearly offer protection against seed-borne pathogens. We also found that some of the endophytes promote plant growth in addition to the disease suppression. Taken together, our results demonstrate agricultural potential of seed endophytes in crop protection.