• The Plant Pathology Journal
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• v.25 no.1
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• pp.1-5
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• 2009

Root rot caused by Cylindrocarpon destructans is one of the most important diseases of ginseng (Panax ginseng C. A. Meyer). Two types of symptoms found in ginseng root rot are black root rot and rusty root (rusty spots), in which disease severities are high and low, respectively. Symptom development and related histopathological changes were examined in an inoculation test on 2-year-old ginseng roots using virulent (Cy9801) and avirulent (Cy0001) isolates of C. destructans under different temperature conditions (13, 18, 23, and $28^{\circ}C$). Black root rot was only induced by Cy9801 in the lower temperature range (13, 18, and $23^{\circ}C$) and not at the higher temperature ($28^{\circ}C$). No black root rot, but only rusty spot symptoms, were induced by Cy0001 at all temperatures tested except $13^{\circ}C$, at which no symptoms occurred on over half of inoculation sites, suggesting disease development was influenced by pathogen virulence and temperature. Wound periderms were formed in all root tissues with rust spot symptoms at $28^{\circ}C$ caused by Cy9801 and at 18, 23, and $28^{\circ}C$ temperatures caused by Cy0001. No wound periderm was formed at $13^{\circ}C$ by either Cy9801 or Cy0001. Light microscopy revealed that the wound periderm was formed by initial cell divisions in cell wall formation and/or additional cell wall layering in parenchyma cells without obvious nuclear division, followed by layering of the divided cells adjacent to the inoculation sites, blocking the spread of the rot. These results suggest that disease development declined at lower temperatures and by the formation of a wound periderm at higher temperatures, and that ginseng rusty root may develop under conditions unfavorable for further disease development of C. destructans.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.86-91
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• 1995

Isolation and pathogenicity of Fusarium spp. from mulberry shoot rot and severity of diseases which were known as bacterial blight were examined on four mulberry varieties in Suwon, Kongju and Chuncheon, A symptom of mulberry shoot rot was initiated long brown spot on young leaves and shoots. It was developed into dark brown spot and produced white mycelia and spores on the diseased symptoms. A symptom of bacterial blight showed leaf rolling and water soaking spot and produced bacterial ooze on leaf and shoot However later stage of upper two types of symptom was hardly distinguished. Severities of shoot rot and bacterial blight were 7.5% and 4.4% in Suwon, respectively. Isolation of Fusarium spp. on shoot rot symptoms was highter than that on bacterial blight symptoms, but isolation of Pseudomonas spp. was higher on bacterial blight symptoms. Trends of pathogenicity of Fusarium spp. and Pseudomonas spp. were similar to inoculation works, and isolations of pathogenic Fusarium spp. from center of symptom was higher than that from 30cm of symptom of all samples in three cultivation areas. Disease severities of shoot rot on variety of Kaeryangppong were 13.9%, 15.9% and 17.2% in Suwon, Kongju and Chuncheon, respectively. However variety of Cheongolppong was highly resistant to shoot rot disease in three cultivation areas.

• The Plant Pathology Journal
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• v.35 no.3
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• pp.189-199
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• 2019

In this research, the relationships among the 31 microsatellite markers with charcoal rot disease resistance related indices in 130 different soybean cultivars and lines were evaluated using association analysis based on the general linear model (GLM) and the mixed linear model (MLM) by the Structure and Tassel software. The results of microsatellite markers showed that the genetic structure of the studied population has three subpopulations (K=3) which the results of bar plat also confirmed it. In association analysis based on GLM and MLM models, 31 and 35 loci showed significant relationships with the evaluated traits, respectively, and confirmed considerable variation of the studied traits. The identified markers related to some of the studied traits were the same which can probably be due to pleiotropic effects or tight linkage among the genomic regions controlling these traits. Some of these relationships were including, the relationship between Sat_252 marker with amount of charcoal rot disease, Satt359, Satt190 and Sat_169 markers with number of microsclerota in stem, amount of charcoal rot disease and severity of charcoal rot disease, Sat_416 marker with number of microsclerota in stem and amount of charcoal rot disease and the Satt460 marker with number of microsclerota in stem and severity of charcoal rot disease. The results of this research and the linked microsatellite markers with the charcoal rot disease-related characteristics can be used to identify the suitable parents and to improve the soybean population in future breeding programs.

• The Plant Pathology Journal
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• v.39 no.6
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• pp.575-583
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• 2023

Fusarium root rot is an increasingly severe problem in soybean cultivation. Although several Fusarium species have been reported to infect soybean roots in Heilongjiang province, their frequency and aggressiveness have not been systematically quantified in the region. This study aimed to investigate the diversity and distribution of Fusarium species that cause soybean root rot in Heilongjiang province over two years. A total of 485 isolates belonging to nine Fusarium species were identified, with F. oxysporum and F. solani being the most prevalent. Pot experiments were conducted to examine the relative aggressiveness of different Fusarium species on soybean roots, revealing that F. oxysporum and F. solani were the most aggressive pathogens, causing the most severe root rot symptoms. The study also assessed the susceptibility of different soybean cultivars to Fusarium root rot caused by F. oxysporum and F. solani. The results indicated that the soybean cultivar DN51 exhibited the most resistance to both pathogens, indicating that it may possess genetic traits that make it less susceptible to Fusarium root rot. These findings provide valuable insights into the diversity and distribution of Fusarium species that cause soybean root rot and could facilitate the development of effective management strategies for this disease.

• Korean Journal of Microbiology
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• v.17 no.4
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• pp.179-186
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• 1979

Rotting bacteria were isolated from decayed root rot of ginseng (Panax ginseng C.A. Meyer), cultured purely, and it's pathogenicity was confirmed by reinoculation test. Two strains (E3, E7) were selected to be tested in more detailed study with respect to their morphological, cutural and biochemical characters. The strains causing red rot of ginsneg were identified as Erwinia carotovora.

• The Plant Pathology Journal
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• v.15 no.4
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• pp.236-241
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• 1999

Sclerotinia twig blight on trees and cottony rot on fruits of Satsuma mandarin were observed in Cheju, Korea in 1996 and 1997. The causal fungus causing citrus twig blight and cottony rot was identified as Sclerotinia sclerotiorum which had cup-shaped apothecia bearing hyaline and clavate asci and periphyses on sclerotium. Symptoms were produced on twigs, developing young leaves, fully developed new leaves, and fruits 2-9 days after wound inoculation, but only on twigs with young lateral buds and developing young leaves by unwound inoculation. The fungus grew well between 10 and $27^{\circ}$, but optimum temperature was $24^{\circ}$ on potato dextrose agar. Most varieties were highly susceptible to S. sclerotiorum, whereas some varieties such as Ichinan were relatively resistant among twelve Satsuma mandarin varieties in the field. This is the first record of Scledrotinia twig blight on trees and cottony rot on stored fruits of Satsuma mandarin in Korea.

• Mycobiology
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• v.46 no.2
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• pp.154-158
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• 2018

Bitter rot caused by the fungal genus Colletotrichum is a well-known, common disease of apple and causes significant yield loss. In 2013, six fungal strains were isolated from Fuji apple fruits exhibiting symptoms of bitter rot from Andong, Korea. These strains were identified as Colletotrichum fructicola and C. siamense based on morphological characteristics and multilocus sequence analysis of the internal transcribed spacer rDNA, actin, calmodulin, chitin synthase, and glyceraldehyde-3-phosphate dehydrogenase Pathogenicity tests confirmed the involvement of C. fructicola and C. siamense in the development of disease symptoms on apple fruits. This is the first report of C. fructicola and C. siamense causing bitter rot on apple fruit in Korea.

• The Plant Pathology Journal
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• v.18 no.1
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• pp.54-55
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• 2002

Soaked black rot symptom was observed on the stem of Angelica acutiloba from July to August 2000 at Kumsan, Chungnam in Korea. This disease usually occurred under humid and high temperature conditions. The lesions on the stem appeared as soft rot with brown elliptical spots, which developed into large black spots at a later stage. When the bacterial isolates from the diseased plants were inoculated onto healthy plants by artificial needle prick method, symptoms similar to that observed in the fields developed. According to the cultural characteristics and pathogenicity of the isolates on the host plant the causal bacterium was identified as Xanthomonas campestris. This study proposed that the disease be named "bacterial black stem rot of A. acutiloba"loba".

• Mycobiology
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• v.45 no.2
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• pp.110-113
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• 2017

Severe root rot was observed in fields of cabbages (Brassica oleracea L.) in 2015 in China. Cardinal symptoms of this disease included root rot and wilting leaves. A fungus was isolated from diseased tissues consistently. Based on the morphological features and molecular analysis of the ITS-5.8S rDNA and D1/D2 domain of the 28S rRNA gene, it was identified as Plectosphaerella cucumerina. This is the first report of P. cucumerina causing cabbage root rot in China and the world.

• Journal of Korean Society of Transportation
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• v.13 no.3
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• pp.53-65
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• 1995

Proposed are model and its solution algorithm for determining the minimum number of high speed exits and their locations. While the previous researches on exit location aimed to minimize the average runway occuancy time (ROT) of an aircraft mix, the proposed approach is to find the minimum number of exits required to meet maximum allowable ROT. The rationale behind the approach is that the capacity of a runway increases as the ROT decreases down to some value, but not any more even though the ROT keep decreasing below the value. Hence, a maximum allowable ROT might be set up without declining the capacity. The problem is transformed into a shortest path problem on a specially constructed network and Dijkstra's labeling algorithms is employed to solve the problem A hypothetical example is provided to illustrate how the algorithms solves the problem.