• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.484-490
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• 1998

Microorganisms associated with seed-rhizome rot of gingers preserved in three underground storage caves were identified with respect to rot types. Rot patterns were grouped into 4 different types : yellow soft rot, brown rot, localized ring rot, and water-soaked rot. Water-soaked rot was highest in frequency with 40% and ring rot the least with 14%. Causal pathogens differed with rot type, yellow soft rot by Erwinia carotovora and Pseudomonas aeruginosa, brown rot by Fusarium solani and Pseudomonas aeruginosa, localized ring rot by F. solani, and water-soaked rot by Pythium spinosum and P. ultimum. Pythium myriotylum, the causal pathogen of ginger rhizome rot which occurs severely in fields was rarely detected from storage seed-rhizomes suggesting its minor involvement with storage rot. Pathogenic Pythium isolates were frequently obtained from both rhizome surface and inner tissues of rotten rhizomes. Detection frequency of Pythium isolates in inner tissues decreased as increasing distance from rhizome surface. In wound-inoculation tests, above pathogens caused a varying degree of rot on healthy rhizomes at 15$^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$ with increasing severity at higher temperatures.

• ALGAE
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• v.39 no.3
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• pp.177-186
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• 2024

Red rot disease is one of the notorious algal diseases that threaten the cultivation of Pyropia in China, and two Pythium pathogens, i.e., Pythium porphyrae and P. chondricola, have been reported as causative agents. To monitor the pathogens, a fluorescent quantitative polymerase chain reaction (PCR) method was developed to quantitatively detect their abundance. Using overlapping PCR and pathogen-specific primer pairs, two pathogen-specific fragments were concatenated to construct an internal standard plasmid, which was used for quantification. For zoospores of known numbers, the results showed that this method can detect as less as 100 and 10 zoospores mL^-1 in a 200 mL solution for P. porphyrae and P. chondricola, respectively. Using monthly collected seawater at 10 sites in Haizhou Bay, a typical aquaculture farm in China, a significantly higher temperature and a significantly lower salinity were determined in December 2021. P. porphyrae was determined to be more abundant than P. chondricola, though with similar temporal distribution patterns from December 2021 to February 2022. When a red rot disease occurred in December 2021, the two pathogens were significantly more abundant at two infected sub-sites than the uninfected sub-site within both seawater and sediment, though they were all significantly more enriched in sediment than in seawater. The present method provides the capability to quantify and compare the abundance of two pathogens and also has the potential to forecast the occurrence of red rot disease, which is of much significance in managing and controlling the disease.

• Journal of the Korean Wood Science and Technology
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• v.36 no.5
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• pp.1-10
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• 2008

Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwood and southern yellow pine was investigated in this study. Brown rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolar were used to examine the decay resistance of the OSB. The OSB test specimens were colonized by brown and white rot fungal mycelium in both the brown and white-rot culture bottles after 8 and 12 weeks, respectively. The wood species and fungus type had the significant effects on the decay resistance. Brown rot decay was evident for all untreated southern pine and mixed hardwood controls. The white-rot decay, however, did not show significant weight loss at both species control samples. The incorporation of ZB and CB composites provides suitable protection against brown-and white-rot fungi. No significant weight loss was observed from the borate treated OSB.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.138-147
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• 2011

Xylogone ganodermophthora, an ascomycetous fungus, is known to cause yellow rot in the cultivated mushroom Ganoderma lucidum. In this study, we investigated the dissemination of this fungal pathogen in G. lucidum grown in cultivation houses. To determine the role of ascospores produced by X. ganodermophthora in disease development, we constructed a green fluorescent protein-labeled transgenic strain. This X. ganodermophthora strain produced a number of ascomata in the tissues of oak logs on which G. lucidum had been grown and on the mushroom fruit bodies. However, the ascospores released from the ascomata were not able to germinate on water agar or potato dextrose agar. Moreover, less than 0.1% of the ascospores showed green fluorescence, indicating that most ascospores of X. ganodermophthora were not viable. To determine the manner in which X. ganodermophthora disseminates, diseased oak logs were either buried in isolated soil beds as soil-borne inocula or placed around soil beds as air-borne inocula. In addition, culture bottles in which G. lucidum mycelia had been grown were placed on each floor of a five-floor shelf near X. ganodermophthora inocula. One year after cultivation, yellow rot occurred in almost all of the oak logs in the soil beds, including those in beds without soil-borne inocula. In contrast, none of the G. lucidum in the culture bottles was infected, suggesting that dissemination of X. ganodermophthora can occur via the cultivation soil.

• Research in Plant Disease
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• v.24 no.2
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• pp.113-122
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• 2018

Ripe rot, Botrytis storage rot and Sclerotinia rot are major fungal diseases that lead to deterioration of fruit quality in Korea. Ripe rot, which is caused by Botryosphaeria dothidea, affects harvested fruits during post-storage ripening, while Botrytis storage rot, caused by Botrytis cinerea, affects harvested fruits during cold storage, and Sclerotinia rot, caused by Sclerotinia sclerotiorum, mainly affects immature fruits on the trees. Major fungal fruit rots tend to affect yellow- and red-fleshed cultivars of kiwifruit more severely because of the sharp increase in their cultivation acreage in recent years in Korea. In this review, we summarize symptoms and epidemiological characteristics of the major fungal fruit rots and propose integrated management methods of the diseases that can be practically utilized at the farmers' orchards in order to prevent the diseases based on our research works and field experiences and the research works of others conducted during the last three decades worldwide.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.1-7
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• 1999

The grain rot of caused by Bukholderia glumae was fist reported in japan in 1955 and then reported in other countries as well as in Korea in 1986. The pathogen causes both seedling and grain rot of rice but it cannot attack any other parts of adult rice plant. Bacterial colonies grow slowly, and are circular and greyish white. The causal bacterium is Gram-negative and rod shape with 1-3 polar flagella, and produce a diffusible yellow-greenish nonfluorescent pigment on King's medium B. Biochemical characteristics such as negative in arginine dehydrolase, oxidase reaction and nitrate reduction and positive in lecithinase, and the utilization of L-arginine and inositol are useful in differentiation of this from other nonfluorescent bacteria pathogenic to rice. This pathogenic bacterium had belonged to the genus of Pseudomonas but recently was transferred to the new genus Burkholderia on the basis of physiological characteristics and DNA-DNA hybridization data. However, other characteristics such as colony heterogenicity or colonial variation after subcultures, phytotoxin, secreting antibiotics, and relationship between yellow greenish pigment production and pathogenicity need to be clarified more. To develop an effective control strategy for this disease, understanding of detailed life cycle of the disease and critical environmental factors affecting disease development is prerequisite. Although 5,435 ha of rice paddy in Korea was infested during 1998, there is no exact estimation of yield losses and distribution of the pathogen. The review will focus on recent progress on the understanding of the bacteriological and ecological characteristics of the causal bacterium and control means of the disease.

• The Korean Journal of Mycology
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• v.50 no.2
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• pp.143-147
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• 2022

Sclerotinia rot symptoms were observed in stringy stonecrop (Sedum sarmentosum) plants growing in vinyl greenhouses in Yeoju and Icheon, Gyeonggi Province, Korea, during disease surveys in spring 2019 and 2020. The initial symptoms were soft rot on stems and leaves at or above the soil line. Furthermore, the symptoms progressed upwards, and the infected plant parts exhibited white to grayish-yellow discoloration. The infestation of diseased plants in the vinyl greenhouses was 1-5% at the two locations examined. Eight isolates of Sclerotinia sp. were obtained from lesions of the diseased plants. The isolates were identified as Sclerotinia sclerotiorum based on their morphological and molecular characteristics. In addition, artificial inoculation tested three isolates of S. sclerotiorum for pathogenicity on stringy stonecrop plants. All the tested isolates caused Sclerotinia rot symptoms in the inoculated plants. The symptoms were similar to those observed in plants from the vinyl greenhouses investigated. This study is the first report of S. sclerotiorum causing Sclerotinia rot in stringy stonecrop.

• The Plant Pathology Journal
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• v.19 no.2
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• pp.79-84
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• 2003

Sclerotinia rot occurred severely on some vegetable crops grown in Namyangju, Yangpyung, and Yangiu areas in Korea in 2001-2002. The crops infected with Scterotinia sp. were Adenophora remotiflora, Armoracia lapathfolia, Angelica acutiloba, Angelica archangelica, Anthriscus sylvestris, Aster tataricus, Beta vulgaris var. cicla, Brassica campestris var. marinosa, Brassica juncea var. laciniata, Chicholium intybus, Lactuca indica var. dracoglossa, Lactuca sativa var. oak-leaf, Petroselinum crispum, and Phyteuma japonicum. The fungus associated with the disease was identified as Sclerotinia sclerotiorum, based on the morphological characteristics of the pathogen. The symptoms were water-soaked spots that enlarged later and became a watery soft rot. Infected parts became yellow and then turned brown, followed by death of the whole plant. White mycelia developed on the upper petioles and leaves and on the soil where these plant parts lay. Then black sclerotia in variable size and shape formed from the mycelial mass. Pathogenicity of the fungus was proven by artificially inoculating each crop. This is the first report of Sclerotinia rot on the listed vegetable crops in Korea.

• Research in Plant Disease
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• v.7 no.1
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• pp.56-59
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• 2001

Stem rot of cacti was found at major cultivating areas including Koyang, Ansung and Eumsung of Korea in 2000. Bipolaris cactivora was consistently isolated from the lesions. The disease occurred on different species of cactus including Cereus peruvianus, C. neopithahaja f. monstruo년, C. tetragonus, Chamaeceresu silestrii, Ch. silvestrii, f. variegata, Gymnocalcium mihanovichii var. friedrichii. G. denudatum var. pentacantha, Hylocereus trigonus and Isolatocereus dumortier. Major symptoms on the cactus species except H. trigohus were almost identical. A rapid rot of the upper portion of the catus stem appeared, and became blackened and somewhat dry. On H. trigonus, the symptom was initially light yellow, water-soaked lesion, turned into light brown and dried to death. According to pathogenicity test, 10 out of 16 cactus species and varieties tested produced identical symptoms as found in the field. However, the fungi did not show pathogenicity to Notocactus scopa, Echinocactus grusonii, Eriocactus leninghausii, Lobivia nealeana, Mammillaria elongata var. intertexta.

• Journal of Ginseng Research
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• v.5 no.1
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• pp.73-84
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• 1981

Effect of environmental factors and host on the growth and outbreak of various ginseng diseases was reviewed Environmental lectors included hydrogen ion concentration, moisture content, temperature, nutrition, and microbiol populations. Age of the ginseng plants in relation to several ginseng disease occurrence was also included in order to formulate the effective control measure for ginseng diseases. Damping-off caused by Rhizoctonia, Pythium, and Phytophthora, greymold by Botrytis, sclerotinia by Scleretinia, and phytophthora blight caused by Phytophthora were usually prevalent during the early growing season of ginseng when temperature is below 20$^{\circ}C$, while anthrac se caused by Colletotrichum, alternaria blight by Alternaria, and bacterial soft rot by Erwinia were so during the latter growing season when temperature is above 25$^{\circ}C$. However, the root rot incited by Fnarium and Cylindrocarpon caused severe damages throughout the growing season. Growth range of the temperature for a pathogen was highly related to the corresponding disease outbreak. Hydrogen ion concentration was highly related to the outbreak of sclerotinia, root rot, and red rot. Most severe outbreak of those diseases where the soil acidity was pH 4.7, pH 6.5- 7.5, and pH6.0-6.5, respectively. Nitrogen content in the soil was also related to outbreak of root rot and red rot. More red rot occurred where NH,-nitrogen is above 30 ppm and more root rot obtained when excessive nitrogen fertilizer applied. Yellow necrosis apparently was related to magnesium especially its ratio with potassium or calcium content in a soil. Fusarium Population showed significant .relations to missing rate of ginseng Plants in a Implanting ginseng field, while that of total bacteria showed similar relations in all ginseng field, However, in six year old ginseng fields, the more the Streptomyces population was, the less the Fusarium obtained. Consequently, less missing rate observed in a field where Streptomyces population was high. Damping-off, root rot, Rhytophthor a blight were mose severe on the nursery and on 2-3 years old ginseng plants, whereas sclerotinia, and grey cod, alteraria blight, anthracnose were severe on 4-6 years old ginseng plants. Root rot caused by Fusarium and Erwinia, however, was also severe regardless of the age of the plants when the roots were injured. Therefore, for the effective control of ginseng root rot most careful control of the disease during the early year should be rendered.