• Research in Plant Disease
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• v.20 no.2
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• pp.95-100
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• 2014

This research was performed to examine the effects of mixed espil and copper hydroxide for powdery mildew prevention on cucumber, tomato and pepper. On prevention effect for powdery mildew on cucumber, results revealed that mixed espil and copper hydroxide with a ratio of 4 : 1, disease incidence rate was 18.9% and prevention effect was 69.9%. Another treatment with a ratio of 8 : 1 showed an disease incidence rate of 18.1% and prevention effect of 71.1%, thus, showed great effectiveness. For powdery mildew on tomato, espil and copper hydroxide were mixed using the ratio 4 : 1, results showed an disease incidence rate of 12.4% and prevention effect of 85.3%. Treatment using the ratio of 8 : 1, results showed an disease incidence rate of 14.3% and prevention effect of 83.0%, thus, showed great effectiveness. For powdery mildew on redpepper, espil and copper hydroxide were mixed using the ratio of 4 : 1 with results showed disease incidence rate of 17.7% and prevention effect of 83.0%. From the results, this treatment is the most effective with the lowest attack rate and highest prevention effect. Deducing from the study, it was found out that using mixed espil and copper hydroxide using the ratios 4 : 1 or 8 : 1 are the most effective method for powdery mildew prevention. Mixed ratio of 4 : 1 or 8 : 1 was most effective for preventing powdery mildew on cucumber and tomato, while the espil and copper hydroxide ratio of 4 : 1 was the most effective method for powdery mildew prevention on pepper.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.326-331
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• 2010

Bacillus subtilis B29, B. subtilis M10 and Streptomyces sp. CC19 obtained from phyllosphere of cucumber plants were selected for biological control of fungal air-borne diseases. For the downy mildew, diseased area of B. subtilis B29, B. subtilis M10 and Streptomyces sp. CC19 showed 0.5%, 20.2% and 42.0%, but that of control was 82.0% respectively, in cucumber seedling test. Incidence of powdery mildew by once application of B. subtilis B29, B. subtilis M10 and Streptomyces sp. CC19 was 2.8%, 3.6% and 12.3%, respectively, whereas that of control was 65.6%. On the gray mold, diseased area of B. subtilis B29, B. subtilis M10 and Streptomyces sp. CC19 was 8.0%, 30.8% and 5.2%, respectively, compared to 81.2% for the control. Therefore, B. subtilis B29 could be a prospective antagonist for biological control of powdery mildew, downy mildew and gray mold of cucumber plant.

• Journal of Applied Biological Chemistry
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• v.52 no.4
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• pp.195-199
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• 2009

To select antifungal surfactants, control efficacy of various nonionic and anionic surfactants on cucumber powdery mildew was evaluated under greenhouse conditions. Among 14 surfactants, pentaetylene glycol monododecyl ether ($C_{12}E_5$), mixture of heptaethylene glycol monodecyl ether and heptaethylene monododecyl ether, and heptaethylene glycol mono-9-octadecenyl ether effectively reduced the development of powdery mildew on cucumber plants. Among the surfactants, $C_{12}E_5$ gave the best control efficacy on the disease and did not show phytotoxic response in cucumber plants. Whereas, fenarimol at a recommended rate (31.3 mg/L) showed less control activity than the surfactant (1,000 mg/L). In addition, mixtures of the surfactant and DBEDC, a protective fungicide, showed high control efficacies against powdery mildews of cucumber and strawberry by additive effect in greenhouse tests.

• Research in Plant Disease
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• v.18 no.1
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• pp.29-34
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• 2012

Powdery mildew and root-knot nematode are very important diseases occurred in cucurbits. This study was conducted to evaluate the resistance of commercial cucurbit cultivars (21 cultivars of cucumber, 9 cultivars of watermelon, 7 cultivars of oriental melon, and 2 cultivars of melon) to powdery mildew and root-knot nematode. At 60 days after transplanting, disease severity of powdery mildew of commercial cucurbit cultivars was investigated. Two cucumber cultivars, 'Gangryeogsamcheok' and 'Sunhobaegchimdadagi' were moderately resistant but the rest of cucumber cultivars were susceptible to powdery mildew. All examined watermelon and oriental melon cultivars were susceptible to powdery mildew, while two melon cultivars ('PMR Turbo' and 'PMR Victory') were resistant. At 45 days after inoculation of seedlings, disease severity of root-knot nematode of commercial cucurbit cultivars were investigated. One cucumber cultivars, 'Baegbongdadagi' was moderately resistant and the others were susceptible to root-knot nematode. In case of watermelon, 'Dalgonakkul' was resistant and the others were moderately resistant or susceptible to root-knot nematode. All examined oriental melon and melon cultivars were susceptible to root-knot nematode. On these results, we recommend that resistant cultivars to powdery mildew and/or root-knot nematode will be more suitable in cultivation of cucurbits for organic farming.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.295-301
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• 2015

We investigated mycophagous ladybird, Illeis koebelei from 12 species of plants infected with powdery mildew in Gyeonggi-do, Korea. The pear tree, Pyrus ussuriensis var. macrostipes (Nakai), was most preferred by I. koebelei. This species was found from early July to early November in pear orchards. There was no entomophagous trace in the gut of I. koebelei without powdery mildew spores in a microscope. All stages except egg and pupa are obligate mycophagous, and the feeding potential is ranked as follows: fourth instar, adults, third instar, second instar, and first instar. Feeding amounts of each stage of I. koebelei were 45.6, 144.4, 372.2, 628.1, and $473.7mm^2$ of cucumber powdery mildew per day. Fourth instar larvae showed highest consumption of cucumber powdery mildew. Developmental periods of four larval instars and adults feeding cucumber powdery mildew were 1.2, 2.3, 2.3, 4.6, and 37.7 days, respectively, at $25^{\circ}C$. In this study, we could not determine the feeding potential of I. koebelei against the cucumber powdery mildew; therefore, and further studies are required to elucidate the potential of this species as a biological control agent, e.g., mass rearing, selection of low toxic chemical agents for Integrated Pest Management (IPM), and control techniques against powdery mildew in agro-ecosystems.

• Research in Plant Disease
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• v.21 no.2
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• pp.58-66
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• 2015

This study was conducted to evaluate control efficacy of a fermented food 'Cheonggukjang' against cucumber powdery mildew caused by Sphaerotheca fuliginea in greenhouse. Sterilized Daepung beans were inoculated with the rice straw as natural inoculum and then incubated for 72 hrs at $42^{\circ}C$ in the household cheonggkjang maker. After 72 hrs of cheonggukjang fermentation, white zymogens were grown on the surface of a sterile Daepung beans. The pH of the 72 hrs fermented soybean was not significantly changed and electrical conductivity was found to increase by about 2 times than before fermentation. The population density of soybean zymogen showed a peak of growth at 60 hrs after fermentation and the concentration of zymogen was $8.2{\times}10^7cfu/ml$. Soybean zymogen form of the colony was divided into three kinds of bacteria and a white and a large colony (WL) was predominant bacteria among those up to 60 hrs of fermentation. To control the cucumber powdery mildew, diluted solutions of cheonggukjang was applied from 6.0% to 30.0% on cucumber leaves and they showed injury symptoms on cucumber leaves in more than 15% of them. However, more than 6.0% diluted cheonggukjang solutions showed more than 77.8% control effect of cucumber powdery mildew at 15 days after treatment. The fermented bacteria of Chenggukjang were well established in the cucumber leaf area at 15 days after treatment. The antifungal activity of 10% diluted cheonggukjang solutions was excellent for four species of plant fungal pathogens, Colletotrichum gloeosporioides, Sclerotinia cepivorum, Rhizoctonia sloani and Phytophthora capsici in the dual culture test. Results indicated that foliar application of Cheonggukjang solution could be used for the control of powdery mildews occurring on organically cultivated cucumber.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.44-49
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• 2000

Objective of this study was to determine the Si distribution and extent of control of powdery mildew diseases of cucumber(Cucumis sativus L.). The distribution of silicon in the leaf epidermis of cucumber plants grown in hydroponic nutrient solutions supplemented with soluble silicates was examined using scanning electron microscopy and energy dispersive X-ray analysis. The silicate absorbed from nutrient solution was translocated into cucumber leaves, and accumulated mainly in the cells surrounding the base of trichome hairs. Base cells surrounding the trichomes also had high levels of Si, Ca, and K. Si levels in the epidermal cells for low Si treatment were not detectable except in the trichome bases. Hyphal lengths of powdery mildew occurring on cucumber leaves cultivated in medium with high concentration of silicate were remarkably shorter than those of cucumber leaves cultivated with low concentration of silicate. There was a negative correlation between hyphal length of S. fuliginea and silicate concentrations.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.37-43
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• 2000

Effects of silicon application on development of colonies of Sphaerotheca fuliginea were examined. Cucumber plants were applied with nutrient solutions amended with different concentrations of soluble silicon and selected leaves were inoculated with known concentrations of conidia of the pathogen. Colony number per leaf, colony area per leaf, and germination rate of conidia of S. fuliginea collected from the inoculated leaves were reduced as silicate concentrations in the nutrient solutions increased from 0.05 to 4.10 mM. The increase in resistance of plants to mildew infection was apparently due to silicate accumulation in leaves, and there was no correlation between cation or ionic strength effects and the silicate treatments. Silicate treatment in growth medium remarkably suppressed powdery mildew development on cucumber. Colonies of mildew fungus were visible with over approx. 38.3% of the mature leaf surface, while that of the leaves in high Si plants was 2.3% observed at 51 days after transplanting. No significant differences were observed between 1.7 mM and 3.4mM silicate treatments. Conidial germination rates were significantly reduced by increasing Si amendments. Conidial germination ranged from 14.7 to 20.3% for plants grown in low Si solution(<1.40 mM), and from 9.0 to 12.4% for plants grown in high Si solution(>1.8 mM). Foliar applications of Si with ${\geq}$ 17.0 mM decreased the number of powdery mildew colonies. Persistence of Si foliar sprays effects on cucumber demonstrated that the 17 mM Si spray applied 4 days before inoculation with S. fuliginea reduced mildew colony formation. The relationship was positive and linear.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.355-365
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• 1994

An extensive ssurvey was conducted on the occurrence of hyperparasites (HP) on powdery milew species in Korea during $1991{\sim}1994$ seasons. As a result, a total of 1070 materials infected with powdery mildew fungi were collected. Of these, 92 ones were infected with the HP; 6 with the unidentified HP and the rest 86 with Ampelomyces quisqualis. This showed infection of powdery mildew species with HP was common phenomenon in nature and A. quisqualis was the most common HP in Korea. To prove the hyperparasitism of A. quisqualis, 24 isolates from 32 collections in 1992 year were successfully cultured. All isolates tested were hyperparasitic to cucumber powdery mildew, Sphaerotheca fusca.

• Plant Disease and Agriculture
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• v.2 no.2
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• pp.30-32
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• 1996

필자는 농촌진흥청에서 한일협력관계로 수행하고 있는 "중복기생균을 이용한 오이 흰가루병의 생물학적 방제연구"를 수행하기 위하여 1996년 6월 18일부터 9월 8일까지 3개월 여간 일본 미에껜에 있는 야채.차시험장을 다녀왔다. 본고에서는 그곳에서 수행한 연구내용과 느낀 점을 연수기로 정리해 보았다.