• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.39-46
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• 2010

Selection procedures for breeding lines resistant to both bacterial wilt caused by Ralstonia solanacearum and Phytophthora blight caused by P. capsici were executed to generations from $F_2$ and $BC_1F_1$ to $F_4$ and $BC_1F_3$ of crosses between a Phytophthora resistant breed, 'Chilbok No. 1' and bacterial wilt resistant accessions introduced from Vietnam during 2009 and 2010. The breeding populations or lines were tested for resistance to P. capsici and resistant plants were selected. The resistant selections were inoculated with R. solanacearum to discard susceptible plants. Resistance to P. capsici was conspicuously improved by selection from $F_2$ and $BC_1F_1$ and the final selections showed a similar level of resistance to P. capsici as a commercial Phytophthora resistant cultivar, Muhanjilju. A few $BC_1F_2$ selections were crossed to a cytoplasmic male sterile line, Chilbok-A, to identify their nuclear genotype interacting with male sterile cytoplasm. Majority of them was fixed to maintainer (Nrfrf) and only two resulted segregating into male sterile and male fertile plants indicating that the pollen parents were heterozygous in the fertility-restoring gene.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.394-398
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• 2015

This research was performed to establish economic threshold (ET) for rice sheath blight disease with the cultivar Odeabyeo. Total yield and yield components, such as the panicle number per hill, the spikelet per panicle, the percent ripened grain and the thousand grain weight were evaluated depending on the disease severity of sheath blight on rice, respectively. Significant negative correlation between the percent of diseased hill (PDH) and total yield was observed (r = -0.93). Moreover, negative correlation coefficients were found between PDH and spikelet per panicle, and percent ripened grain (r = -0.66 and -0.77, respectively). There were no correlations between PDH and the panical number per hill, and a thousand grain weight, respectively. In this study, economic threshold level on sheath blight disease on rice was established on 7.8% of PDH.

• Research in Plant Disease
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• v.22 no.1
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• pp.44-49
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• 2016

The twig blight symptoms were observed in Chinese magnolia vine (Schisandra chinensis) at Mungyeong city, Gyeongbuk province, Korea in June 2015. The typical symptoms of infected plant were shriveled and wilted in leaves which led to blight resulted in death. Based on the morphological characteristics, the isolate was suspected as Botryosphaeria sp. Inoculation of isolated pathogen was performed to identify its pathogenicity according to Koch's postulates. Re-isolated fungi from the inoculated stem was showed same morphological characteristics with original pathogen. Phylogenetic analysis was performed using combined sequence of rDNA internal transcribed spacer region, EF1-${\alpha}$ and ${\beta}$-tubulin gene. The isolated pathogen was identified to the B. dothidea by phylogenetic analysis. This is the first report of twig blight on S. chinensis caused by B. dothidea in Korea.

• Research in Plant Disease
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• v.22 no.3
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• pp.202-207
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• 2016

Rice bacterial blight and blast are devastating rice diseases in worldwide. Riboflavin, vitamin B2, is an essential nutrient for human health, and is known to be as a growth regulator and as a plant defense activator against pathogens in plants. In this study, we investigated possibility of increasing internal vitamin B contents and inducing resistances against rice diseases by external foliar application of a riboflavin-based formulator called BioDoctor. In planta bioassay indicated that pretreatment of the foliar application of 1,000-fold or 500-fold diluted BioDoctor significantly induced disease resistance against rice blast and bacterial blight. In addition, about four fold higher levels of riboflavin contents were detected in the BioDoctor treated rice grain and stem compared to those of untreated rice. Our results indicated that foliar application of the riboflavin has a great potential to control plant diseases and to enhance internal vitamin contents in rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.14-22
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• 1989

Rice varieties showing different degree of resistance were compared with their yield losses due to the damage of sheath blight disease in field condition through 1985 to 1986. Gayabyeo showed the lowest value of disease severity among 5 varieties tested in 1985 and 8 in 1986. and Taebaekbyeo, Kwanakbyeo and Labelle showed higher value of disease severity under the condition of artificial or natural disease inoculation. Grain yield of Gayabyeo, a moderate resistant rice variety, was reduced by 0.3 to 5％ in the rate due to sheath blight disease damage and Taebaekbyeo. a susceptible variety. showed the highest in the rate of yield loss, 6.8 to 25.8 ％. The matured grain rate and 1000-grain weight of the matured tiller were decreased when the developing disease lesion reached to the flag leaf, and then panicle weight was decreased more than 25 ％ compared with panicle of healthy culm. In conclusion, Gayabyeo showed the lower rate of yield loss because of slow development of disease to the upper leaves after initial disease occurence on the lower parts of rice plants.

• Korean journal of applied entomology
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• v.22 no.1 s.54
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• pp.21-25
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• 1983

To develop forecasting methods of rice sheath blight caused by Rhizoctonia solani, two rice cultivars Jinheung (Japonica type) and Yushin (Tongil type) were used from 1976 to 1981. Severity of rice sheath blight disease at maturing stage was estimated by top lesion height, percentage of top lesion height vs. plant height in July and lesion index on September 11. The relationship between top lesion height on July 11 and degree of damage at maturing stage for a cultivar Yushin was represented by the equation of Y=4.64x-13.2, and $r=.840^{**}$, where Y is degree of damage by shea4h blight at maturing stage and x is top lesion height on July 11. Considering the percentage of infected hills/stems was rapidly increased from July 11 to August 1, the most effective period and time for fungicide spray were considered July 15 and July 25 or July 25 and August 5.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.1-7
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• 2011

In order to enhance the fungicidal activity of the thifluzamide formulation against rice sheath blight, the surfactants which was able to facilitate the foliar uptake or increase the leaf deposit of thifluzamide on rice plants were selected, and the formulations containing the surfactants were tested to compare the fungicidal efficacy against the rice sheath blight with a control WP formulation. The WP suspension containing dodecaethylene glycol monohexadecyl ether as an activator increased the foliar uptake of thifluzamide on rice plants, but its fungicidal efficacy against rice sheath blight was decreased. The addition of the combined surfactants with either heptaethylene glycol monoisododecy ether or heptaethylene glycol monotridecyl ether and sodium dioctylsulfosuccinate to WP suspension increased the leaf deposition of thif1uzamide at around 5 times of that without a spreader-sticker that median control concentrations of thifluzamide against rice sheath blight were decreased to 4.4 mg $L^{-1}$ and 3.4 mg $L^{-1}$, respectively.

• Research in Plant Disease
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• v.11 no.1
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• pp.77-79
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• 2005

Leaf blight of kudzu was found in Jeonbuk province in 2002. Water-soaked lesion appeared on leaves, and young stems and gray green blight sypmtom expanded from margin to main vine of leaves. As the disease became severe, blighted leaves and shoots turned dark brown and then collapsed. The causal pathgen showed initially white aerial mycelium and turned brown to gray. Mycelia were branched at 90o angles and multinucleate in one cell. It formed sclerotia on PDA. Slerotia were irregular, globose and 0.5~3.0 mm in diameter. The causal fungus of leaf blight was identified as Rhizoctonia solani Kuhn based on the cultural and morphological characteristics. This is the first report on leaf blight of kudzu caused by R. solani in Korea.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.307-312
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• 2023

Water chestnut is fruits of Trapa natans var. bispinosa grown wild in Korea. In this study, water chestnut was investigated for anti-pigmentation. Treatment with ethanolic extracts of water chestnut significantly reduced production of melanin in α-MSH simulated B16F10 cells. At 200 ㎍/mL ethanolic extracts of water chestnut, melanin contents were repressed by 43.26% compared to the control group. Additionally, ethanolic extracts of water chestnut reduced expression and activity of tyrosinase, key enzyme in melanogenesis, in α-MSH simulated B16F10 cells. Ethanolic extracts of water chestnut downregulated tyrosinase activity and expression to 23.65% and 62.35%, respectively. These results suggest that ethanolic extracts of water chestnut might be used as a promising whitening ingredients for inhibition of α-MSH-induced melanin synthesis and pigmentation.

• Research in Plant Disease
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• v.29 no.4
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• pp.433-439
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• 2023

Bacterial leaf blight in carrot is one of the most important diseases in the worldwide. In the past decade, its introduction into Korea is causing great concern due to the potential damage to carrot crops domestically. This bacterial disease is caused by Xanthomonas hortorum pv. carotae (Xhc). This study aimed to isolate and identify bacterial strains from the soil of carrot farms in Jeju Island. The bacterial isolates showing characteristics similar with those of Xhc were selected when cultured on artificial media. Through DNA sequencing and analysis based on NCBI data, some of the selected bacterial strains were identified as Xhc. Furthermore, the bacterial strains caused the typical symptom of bacterial leaf blight after inoculation on carrot leaves. The results of this study showed the potential establishment of Xhc in the soil of Jeju Island and it may be valuable data for establish a strategy preventing the domestic spread of carrot bacterial leaf blight in the future.