• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.50-56
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• 2001

Thirty-three bacterial and fungal strains were isolated from the rotten soybeans and soybean sprouts to isolate pathogenic microorganisms which cause soybean sprouts rot during soybean sprouts cultivation. In pathogenicity tests of the isolates on soybean sprouts, two isolates(K-17 and K-28) caused soybean sprouts rot and were identified as Erwinia carotovora and Fusarium sp., respectively. To isolate antagonists aganist K-17 and K-28 pathogens, bacteria were isolated from various soybean-cultivated soils and screened by the inhibition zone method. A bacterial isolate(J-232) which inhibited growth of both pathogens was identified as Pseudomonas fluorescens and further examined. The culture filtrate of P. fluorescens J-232 (dilution rate of 500 times) inhibited the growth of Erwinia carotovora K-17 and Fusarium sp. K-28 both on potato dextrose agar medium and on soybean sprouts cultivated in vessel. The development of soybean sprouts rots was observed during cultivation by inoculation of soybean seeds with culture filtrate of both pathogens. The combined inoculation of soybean seeds with culture filtrate of antagonistic bacterium and that of pathogens prevented soybean sprouts rot, and the growth of soybean sprouts was similar to that of control. The soybean sprouts inoculated with antagonists culture filtrate alone did not develop soybean sprouts rot, and the growth of the seedlings was shown to be slightly promoted as compared with that of control.

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.132-138
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• 1995

우리나라 사과원에서의 토양병 발생현황과 발생실태를 1991년부터 1993년까지 3년간 조사한 결과, 전체 조사주수의 약 8.1%가 각종의 토양 병원균에 감염되어 있는 것으로 나타났다. 토양병 중 자주날개 무늬병의 발생빈도가 5.1%로 가장 높게 조사되었으며, 흰날개무늬병과 역병의 이병주율은 각각 2.5%와 0.2%로 조사되었다. 자주날개무늬병에 감염된 나무에서는 잎의 황화 및 조기낙엽, 신초생장 억제, 과실 생육 불량 등의 지상부 병징이 관찰되었고, 지하부 뿌리 표면에는 적자색 실모양의 균사나 균사속이 관찰되었다. 감염된 뿌리의 표피는 쉽게 벗겨지고 목질부로부터 잘 이탈되는 특징이 있었다. 흰날개무늬병균에 감염된 나무의 뿌리는 흰색의 균사 혹은 균사막으로 싸여 있으며 이 균사막은 시간이 경과하면 회색 내지 흑색으로 착색되었다. 굵은 뿌리의 표피를 제거하면 목질부에 백색 부채모양의 균사막과 실모양의 균사속을 확인할 수 있었다. 이 병원균은 목질부까지 부패시키므로 병의 증세가 심하게 나타났다. 자주날개무늬병은 새로 개원한 10년 이하의 과원에서 발생이 많았다. 자주날개무늬병은 왜화도가 높은 대목에서 발병율이 높았으나 흰날개무늬병은 대목의 종류에 관계없이 발명되었다. 자주날개무늬병은 식양토 과원에서 발생이 많았으며 흰날개무늬병은 사양토 과원에서 발생이 많았다.

• Journal of Life Science
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• v.22 no.7
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• pp.987-990
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• 2012

Mungbean sprout rot is one of the most serious problems of the commercial mungbean sprout industry. In this study, 70 strains of mungbean sprout rot pathogens were isolated from rotten sprouts at different time intervals. The pathogenicity of the isolated pathogens was tested. The highly pathogenic strain (YV-St-033) was identified as Pseudomonas sp. by 16S rRNA gene sequencing. In phylogenetic analysis, the YV-St-033 strain was grouped with P. mosselii, P. putita, P. fluorescens, P. entomophila, and P. lecoglossicida. The results of the 16S rRNA gene sequence analysis revealed that the YV-St-033 strain shared the highest sequence identity (more than 99%) with the P. mosselii R10 strain. The mungbean lines of Yeungnam University germplasm were screened against the YV-St-033 strain. Based on the growth rate of the sprouts after 3 days of inoculation with the pathogen, the YV148 line was highly resistant to the pathogen. The remaining lines were either partially or fully infected. The highly resistant line YV 148 is suitable for future breeding programs due to their thin sprouts and fast growing nature.

• Microbiology and Biotechnology Letters
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• v.12 no.4
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• pp.299-304
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• 1984

Saprophytic microorganisms of onion bulbs in Korea were confirmed, and effects of temperature, humidity and fumigation by Tetrachloro isophthalonitrile on Botrytis-rot were investigated in order to decrease storage loss of onions. Dominant saprophytes were Botrytis, Penicillium and Fusarium as molds which were all pathogens, and Erwinia and Pseudomonas as bacteria of which Pseudomonas was a non-pathogen. Botrytis-rot was most effectively suppressed by temperature. At $0^{\circ}C$, the incubation days at which 50% area of one onion leaf-fragment (2.5$\times$2.5cm) inoculated by Botrytis was rotten were 26.2 days and the rotting was delayed more by 21.8 days than at $25^{\circ}C$. For humidity, the effect was pretty insignificant in contrast with temperature effect. At RH 70% and $0^{\circ}C$, the incubation days at which 50% area of one onion leaf-fragment was rotten were 28.0 days and the rotting was delayed more by 1.8 days than at RH9o% and $0^{\circ}C$. By fumigation, the rotting was delayed by 3.8 days at RH 70% and $0^{\circ}C$. In case of slightly infected samples, temperature effect was reduced and the effects of humidity and fumigation were ignored, which implies that storage samples should be healthy.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.453-456
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• 2000

Antifungal activities of domestic plants were examined to develope natural antimicrobial agents, able to protect citrus fruits from spoiling microorganism during their storage. A fungus was isolated from citrus fruits' storage and identified to Penicillium sp. CF-301, based on the morphological characteristics of conidiophore and conidia; flask shape of phialide, simple branching type of conidiophore, and columnar shape of conidial head, in malt extract agar and potato dextrose agar media. Chloroform extracts of Juniperus chinesis Linnaeus, J. chinesis var. horizontalis showed remarkable antifungal activities against Penicillium sp. CF-301.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.729-732
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• 2000

Antifungal activities of domestic plants were examined to develop natural anti-microbial agents, able to protect onion from spoiling microorganisms during their storage. A fungus was isolated from spoiling onion and identified to Penicillium sp. ON-211, based on the morphological characteristics of conidiophore and conidia. Chloroform extracts of Juniperus chinesis Linnaeus, Juniperus. chi. var. horizontalis, water extract of Thujs orientalis Linnaeus' seed and the n-hexane extract of Juniperus. chi. var. horizontalis N. showed remarkable antifungal activties against this fungus.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.130-133
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• 2004

Leaf blight and fruit rot of sweet persimmon (cv. Fuyu) caused by Pestalotia diospyri were observed during the growing season and postharvest such as storage and transport, respectively. Typical symptoms on leaves developed with small brown spots and were later reddish brown colors. In the storage fruit, the white mycelial mats formed between fruit and calyx. The pathogenic fungus was isolated from infected fruits and cultured on potato dextrose agar (PDA). Colony color of the fungus was white at first on PDA. Conidia were ovoid or fusiform, 5 cells, middle 3 cells were olive, upper and lower 2 cells were colorless, and their size were $16{\sim}22\;{\times}\;6{\sim}8\;{\mu}m$. They had were $2{\sim}3$ appendage at basal cell and size $9{\sim}18\;{\mu}m$. Based on the cultural and mycological characteristics and pathogenicity test on host plants and fruits, the fungus was identified as Pestalotia diospyri Syd.&P. Syd. This is the first report on the leaf blight and fruit rot of sweet persimmon caused by Pestalotia diospyri in Korea.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.362-366
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• 2001

This survey was carried out to investigate the effect of flooding by heavy rain on growth characteristics and disease incidence of 'Fuji'/M.26 mature apple tree in 1998 at Kyongbuk province. The surveyed regions were Andong, Uisung, and Gunwi area. The six orchards were selected from one area, totally 18 orchards were surveyed. The flooded depth of surveyed orchards was from 70 to 350 cm, and the flooded duration was from 6 to 72 h. Defoliation ratio, number of abnormal budding, and flowering per tree were increased along with the increment of flooded depth and duration. Rooting ratio was decreased rapidly with the increment of flooded duration, and dead root ratio was 16.2% in flooded orchards. Marssonia blotch (Diplocarpon mali), white rot (Botryosphaeria dothidea) of fruit, and phytophthora fruit rot (Phytophthora cactorum) incidence were increased in flooded orchards. The analysis results of pearson correlation coefficient among surveyed items showed that higher relationship of abnormal growth characteristics and increment of disease incidence of 'Fuji'/M.26 apple trees with flooded duration than with flooded depth. With these results, the flooded depth was found to be the main factor for the abnormal growth characteristics and disease incidences of 'Fuji'/M.26 apple trees.

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.116-119
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• 1995

Occurrence of soft rots was observed on chicory that was massively grown in-In-jae, Kangwon-Do, Korea. At first, a creamy lesion was appeared on the chicory root, which was enlarged slowly in diameter and in depth. The affected root area became soft and mushy. This eventually resulted in wilting and death of the aboveground parts of the chicory. The causal organism isolated from the lesions was identified as Erwinia carotovora subsp. carotovora based on the physiological and chemical characteristics, and on the results of the Biolog Program (Biolog Inc. U.S.A.). Since E. carotovora subsp. carotovora is the first described bacterium that causes soft rot on chicory in Korea, we proposr to name the chicory disease caused by E. carotovora subsp. carotovora as "bacterial soft rot of chicory".

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.55-63
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• 1977

As the important pathogens of potato storage diseases, Fusarium solani, F. reseum, F. oxysporum, and Erwinia carotovora were isolated from rot potato tubers. The cut potato pieces of the three cultivars, Epicure, Irish Cobbler, and Superior were held in moist chambers of $4^{\circ},\;14^{\circ},\;24^{\circ},\;and\; 34^{\circ}C$ and 7 days and then rated for suberin and periderm development. The cut potato pieces thus treated were inoculated with the four organisms and held at $24^{\circ}C$ for 9 days and then rated for decay. As the temperature and period of holding increased, more suberin and periderm were developed with decrease in decay. Although there were differences in pathogenicity of the organisms, varietal reaction and protective barrier development, the effect of temperature and holding period had greater importance for decay prevention. At $4^{\circ}C$ within 7 days of holding period the potato pieces developed no protective barrier with severe decay. It is required to avoid placing cut potatoes directly in cold storage of the low temperature. At $34^{\circ}C$ the pieces developed abundant protective barriers even though decay occurred in somecases. Practically no decay was found with moderate protective barrier development after 3 days and 5 days at $24^{\circ}C\;and\;14^{\circ}C$, respectively. Since the potato pieces decayed occasionally during the holding period when they were held at the higher temperature, the holding at $14^{\circ}C$ for longer than 5 days is considered to be feasible for prevention of storage rots.