• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.258-262
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• 2011

This study was carried out to investigate the effect the water content in substrates as according to growth stage on the growth and yield of paprika in summer hydroponics. Treatments of I, II and III were composed of 55-65-60, 50-60-55 and 45-55-50 % in water contents of growth stages, respectively. Time domain reflectometry (TDR) sensors were used in a drip irrigation system. The early growth of paprika was increased by high medium water content of treatment I. Mean fruit weight was not affected by medium water content, but the fruit number per plant and yield were increased at high medium water content of treatment I. The yield of treatment I was higher than that of treatment II and III. The incidence of brown stem fruit, blossom end rot and sunburn was decreased with increasing water content of medium. Occurred in the low water content of medium. The nitrogen (N) was higher content in brown stem fruit than normal stem, but mineral contents such as potassium (K), calcium (Ca), magnesium (Mg) etc. were not affected.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.1-8
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• 2012

Quality deterioration during storage such as weight and fruit firmness loss after harvest is one of the main problems in summer cultivation of mini paprika. Objective of this study was to determine appropriate storage temperature and duration in the mini paprika('Hivita Yellow' and 'Hivita Red'). More fruit firmness loss during storage was observed at higher storage temperature. Fruit firmness of 'Hivita Yellow' at $20^{\circ}C$ was $99.6g/cm^2$ after a 5-day storage whereas that decreased by $73.0g/cm^2$ after a 40-day storage. Storing 'Hivita Yellow' at $8^{\circ}C$ showed the lowest fruit firmness loss with 109.7 and $92.7g/cm^2$ after a 5-day and a 40-day storage, respectively. In both cultivars, soluble solids content of fruits was higher at $20^{\circ}C$ than at 4, 8 and $12^{\circ}C$. Higher temperature triggered more water loss of the fruits with more occurrence of soft rot and shriveling symptoms. The changes in electrolyte conductivity of fruits during storage was higher in the fruits at lower temperature. Fruit stored at $20^{\circ}C$ showed the highest respiration(more $CO_2$ and less $O_2$) during storage than fruits at the other storage temperatures.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.11a
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• pp.66-71
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• 1997

우리나라에서 토마토재배는$^{10)}$ 94.7%가 시설재배를 하고 있는데 연작에 따른 각종 장해가 발생하고 있다. 연작은 여러 가지 생리적 장해 또는 병충해의 만연$^{8)}$ 이 있으나 가장 치명적인 것이 뿌리썩음시들음병(근부위조병, Fusarium oxyporum Schl. f. sp. lycopersici Snyder et Honsen, race J$_3$)으로 한번 발병하면 방제가 되지 않는다. (중략)

• Research in Plant Disease
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• v.7 no.1
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• pp.11-15
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• 2001

Root rot of Cucurbitaceae plants, caused by Monosporascus cannonballus, is one of the recently described diseases in Korea. The distribution and pathogenicity of M. cannonballus were examined by field and in vitro experiments. Root rot caused by M. cannonballus occurred on melon, oriental melon, watermelon and cucumber plants. In two years of disease survey, the disease occurred at 10 and 32 fields in 1997 and 1998, respectively, which were located at Kimhae, Chinju, and Namhae in Kyeongnam province, at Kwangyang in Chonnam province, at Kwangju city, and at Yeoju and Inchon in Kyeonggi province. The disease progress in a melon field at Namhae was not observed until the middle stage of plant growth, but rapidly increased at the fruit maturing stage, resulting in more than 50% yield loss. Isolation rate of M. cannonballus was 36.7% from wilted hosts. Fusarium oxysporum and Rhizoctonia solani were also frequently isolated. In vitro test, seedlings wilted after 7∼14 days of inoculation, and perithecia were formed in infected roots 21 days later. Two cucumber cultivars, Baekbong and Eunhwa, were resistant to the disease.

• The Korean Journal of Mycology
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• v.35 no.1
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• pp.54-57
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• 2007

Rhizopus soft rot caused by Rhizopus stolonifer occurred on banana (Musa sapientum) in the box at Jinju City Wholesale Market of Agricultural Products at Gyeongnam province in Korea. The infected fruits were rapidly water-soaked, softened, blackened and eventually rotted. They were infected from wounds at harvest time. The colony of the isolate from the infected fruit was white to light brown and formed many sporangiospores. The optimum growth temperature of the fungus on potato dextrose agar was $30^{\circ}C$. Sporangiophores were $12{\sim}26\;{\mu}m$ in width. Sporangia were globose or hemispheric, white at first and changed gradually to black, and $83{\sim}195\;{\mu}m$ in size. Columella were hemispheric, and $72{\sim}125\;{\mu}m$ in size. Sporangiospores were irregular round or oval, brownish-black and $9{\sim}20{\times}7{\sim}8\;{\mu}m$ in size. On the basis of symptom, mycological characteristics and pathogenicity to banana, the causal fungus was identified as Rhizopus stolonifer. This is the first report of Rhizopus soft rot by R. stolonifer on banana in Korea.

• 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.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.322-327
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• 2005

Regression models for determining infection periods of apple white rot were developed based on conidial germination and appressorium formation of Botryosphaeria dothidea. A total of 120 apple fruits were inoculated with the fungal conidial suspension and subjected to 6 temperatures and 10 wetness periods. Conidia germinated and produced appressoria, exhibiting swollen tips of germ tubes on the fruit surface. Conidial germination (G) increased with temperature (T) and wetness period (W), and was described as $G=-89.273+7.649T+7.056W-0.109T^{2}-0.085W^{2}-0.066TW(R^{2}=0.75)$. Less than 2 hr of wetness period were enough for conidia to germinate at 25 to $30^{\circ}C$. Effects of temperature and wetness period on appressorium formation (A) could be explained as $A=-1.540-2.375W+0.045W^{2}+0.213TW(R^{2}=0.77)$. The relationship between conidial germination and appressorium formation ($A_g$) was described as$A_g=0.381-0.227G+0.005G^{2}(R^{2}=0.67)$, suggesting that conidial germination may have to reach approximately $43.7\%$ to initiate appressorium formation. Using the regression equation for conidial germination and the criterion of $43.7\%$ conidial germination, an infection model was developed to determine infection periods based on temperature and wetness period. The infection model with the criterion of $43.7\%$ conidial germination was apparently more conservative than the appressorium formation model in determining possibility of apple infection. The infection model seemed sensitive to variable weather conditions, suggesting possible use of the model for timing fungicide sprays to control white rot of apples in practice.

• The Plant Pathology Journal
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• v.39 no.3
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• pp.275-289
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• 2023

Fungal isolates from infected Chinese quince trees were found to cause black rot in Yeongcheon, Gyeongsangbuk Province, Korea. The quince leaves withered and turned reddish-brown and fruits underwent black mummification. To elucidate the cause of these symptoms, the pathogen was isolated from infected leaf and fruit tissues on potato dextrose agar and Levan media. Several fungal colonies forming a fluffy white or dark gray mycelium and two types of fungi forming an aerial white mycelium, growing widely at the edges, were isolated. Microscopic observations, investigation of fungal growth characteristics on various media, and molecular identification using an internal transcribed spacer, β-tubulin, and translation elongation factor 1-α genes were performed. The fungal pathogens were identified as Diplodia parva and Diplodia crataegicola. Pathogenicity tests revealed that the pathogen-inoculated fruits exhibited a layered pattern, turning brown rotting; leaves showed circular brown necrotic lesions. The developed symptoms were similar to those observed in the field. Fungal pathogens were reisolated to fulfill Koch's postulates. Apples were inoculated with fungal pathogens to investigate the host range. Strong pathogenicity was evident in the fruits, with browning and rotting symptoms 3 days after inoculation. To determine pathogen control, a fungicidal sensitivity test was conducted using four registered fungicides. Thiophanate-methyl, propineb, and tebuconazole inhibited the mycelial growth of pathogens. To the best of our knowledge, this is the first report on the isolation and identification of the fungal pathogens D. parva and D. crataegicola from infected fruits and leaves of Chinese quince, causing black rot disease in Korea.

• Research in Plant Disease
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• v.23 no.1
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• pp.49-55
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• 2017

The previous study showed that die-back of apple trees caused by soil-borne diseases was significantly high in the apple orchards in Chungbuk province. The correlation between dieback ratio and cultivation environment in apple orchards infected by soil-borne diseases was investigated in this study. The dieback ratio of five orchards diseased by violet root rot and five places infected by white root rot showed significantly positive correlation with Ca content and available $P_2O_5$ content in soil, respectively. Whereas, the dieback ratio of fourteen orchards diseased by Phytophthora root rot was not significant. Subgrouping of cultivation environment analysis showed that the slope degree of orchard and the number of fruit setting also affected the dieback ratio caused by violet root rot and Ca content in soil also affected the dieback ratio caused by white root rot. It showed that the slope degree, soil texture, Mg and Ca content affected the dieback ratio caused by Phytophthora root rot. These results can be applied to reduce die-back ratio by the modification cultivation environment for each soil-borne disease.

• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.585-590
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• 2007

Rhizina undulata is the fungus, which causes Rhizina root rot on coniferous trees. Nested-PCR using ITS-specific primer was applied to detect R. undulata from the soils of Japanese black pine (Pinus thunbergil) forests infested with the disease in Seocheon, Chungnam Province, South Korea. Soil samples were collected from four different sites, both dead trees and fruit bodies of R. undulata were present, dead trees only present, fruit bodies only present, and both were absent. Nested-PCR products specific to R. undulata ITS-region were amplified. Positive reactions were found in some samples from the sites, where dead trees and fruit bodies of R. undulata were absent as well as where both of those were present. R. undulata was mainly detected in the soil samples from the depth of 5~20 cm under the soil surface. These results show that the nested-PCR could be used to diagnose the presence or potential infestation of R. undulata in the soils of pine forests.