• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.53.1-53
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• 1999

• The Plant Pathology Journal
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• v.16 no.4
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• pp.206-210
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• 2000

The effect of the electrolyzed oxidizing water on Sphaerotheca fuliginea was investigated with germination and sporulation of the fungal conidia. The sporulation was inhibited by the electrolyzed oxidizing water of pH 2.5, 3.5, and 4.5, but was not inhibited by the distilled water adjusted pH with 1N-HCL solution. However, the electrolyzed oxidizing water did not affect conidial germination. The oxidation-reduction potential at pH 2.5 and pH 3.5 of electrolyzed oxidizing water were 1130 mV and 1060 mV, respectively, but those of distilled water adjusted with HCL solution were 550 mV and 490 mV, respectively. When the electrolyzed oxidizing water of ORP over 1100 mV was sprayed on cucumplanting, the disease severities of powdery mildew were about 8.5% and 19.2%, respectively. Disease severity of a standard control (triflumizole 30% WP, $500\textrm{mg}\textrm{/L}$) was about 3.0%, while that of plants without electrolyzed oxidizing water was to 45.8%.

• 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.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.349-353
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• 1994

An isolate 90-GT-302, identified as Kitasatosporia kimorexae, was found to produce antibiotics that induce mycelial swelling in Magnaporthe grisea, and Fusarium solani. The strain produced at least 5 antibiotics. Among them, the main active compound designated as kimorexin A was isolated and its physico-chemical properties and biological activities were examined, and as a result was found to be of the thiopeptide antibiotic. A comparison between the properties of kimorexin A and those of the known thiopeptide antibiotics led us to conclude that kimorexin A was a new thiopeptide polythiazolyl antibiotic. Kimorexin A showed a narrow antimicrobial spectrum against very limited genus of phytopathogenic fungi. It prevented host plants from infections of Rhizoctonia solani and absolute parasitic fungi, such as Sphaerotheca fuliginea and Puccinia recondita, almost completely at the treatment concentration of approximately 20 ppm.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.85-90
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• 1996

대황 추출물(RK)과 화학약품 1, 8-dihydroxy anthraquinone(AK)을 제제화하여 오이 흰가루병에 대한 약효, 약해 및 어독성을 조사하였다. 제제화한 RK와 AK 약제를 하우스에서 500배, 1000배 희석농도로 처리했을 경우 오이 흰가루병에 대하여 100%의 방제효과를 나타냈고, pot에서 2,000배, 3,000배, 5,000배 희석농도로 처리했을 때 모두 75% 이상의 방제효과를 나타냈다. 또 노지에서 4,000배, 5,000배 희석농도로 처리해도 75.3% 이상의 방제효과를 나타냈다. RK 약제는 250배 희석농도에서 오이에 약해가 없었으나 AK 약제는 250배 희석농도에서 약해가 있었다. 어독성은 두 약제 모두 반수치사농도(TLm)가 2ppm 이상으로 독성은 낮은 것으로 판정되었다.

• Research in Plant Disease
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• v.10 no.3
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• pp.159-166
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• 2004

This study were carried out to identify pathogens and determine the seasonal occurrence and chemical control of safflower (Carthamus tinctorius) diseases from 2000 to 2002 in Gyengbuk province, Korea. Major diseases of safflower were, anthracnose caused by Colletotricum acutatum in open field, and gray mold by Botrytis cinerea in rain sheltered plastic house. Other diseases occurred were powdery mildew caused by Sphaerotheca fuliginea, collar rot by Sclerotium rolfsii, leaf spot by Alternaria carthami and A. alternata, rust by Puccinia carthami, root-rot and stem-rot by Phytophthora cactorum, root-rot and wilt by Fusarium oxysporum and damping-off by Pythium ultimum. Seasonal occurrence of anthracnose on safflower has begun from late April, and increased until harvesting, especially rapid increased after rainfall during stem elongation season that is from May to June. In open fields, maximum incidence of anthracnose was 67 ％ in late July. But in rain-sheltered plastic house, it was very low, about 5％ in July. Gray mold caused by Botrytis cinerea was most important disease in rain-sheltered plastic house cultivation. Maximum incidence of gray mold on floral head was 27.4％, whereas other diseases occurred below 1 ％. In the test of the chemical control of the safflower anthracnose, metiram WP, carbendazim$.$kasugamycin WP and iminoctadintris$.$thiram WP were the highest controlling chemicals. In chemical control of gray mold, iminoctadintris$.$thiram WP, fluazinam WP and iprodion WP showed highest controlling effects.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.255-260
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• 2003

Silicon is known to accumulate in plants and results in greater resistance to diseases and insect pests. In this study, we investigated the effect of silicate fertilizer applied in soil on the development of powdery mildew of oriental melon. Oriental melon seedlings of four-leaf stage were transplanted and grown in a plastic film house. Silicate fertilizer was applied to maintain soil available $SiO_2$ level of 200 mg/kg one week before transplanting. Fungicide triflumizol was sprayed three times; one, two, and three weeks after transplanting. Sphaerotheca fuliginea was inoculated 2 weeks after transplanting. The number of infected leaf and the number of fungal colony in leaves were measured one, two, and three weeks after the inoculation. Three weeks after the fungal inoculation, in the treatment of fungicide triflumizol. infected leaf numbers and number of colony per leaf were reduced by 10 and 58%, respectively. In the silicate fertilizer treatment, infected leaf numbers and numbers of colony per infected leaf were suppressed only by 6 and 16%, respectively, and the efficacy was lower than that of the fungicide triflumizol. The combined treatment of silicate fertilizer and the fungicide suppressed powdery mildew more effectively, and infected leaf numbers and numbers of colony per leaf were reduced by 31 and 80%, respectively. These results indicate that although silicate fertilizer itself is not much effective in the suppression of powdery mildew, it can significantly enhance the efficacy of the fungicide.

• The Plant Pathology Journal
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• v.27 no.1
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• pp.85-88
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• 2011

Podosphaera fusca (syn. Sphaerotheca fusca, S. fuliginea) is a causal agent of powdery mildew infections on Zinnia elegans, and has been documented in Korea since 1967. An outbreak involving about 1,000 plants in October 2008, in Yangpyeong, Korea, was caused by Golovinomyces cichoracearum. Further surveys of zinnia powdery mildew from 2008-2010 confirmed the widespread occurrence of Zinnia-Golovinomyces association in Korea. Chasmothecia of this fungus have not been found on Z. elegans in Korea. Analysis of internal transcribed spacer rDNA from five Korean collections confirmed the powdery mildew as G. cichoracearum. Comparison with the those from GenBank revealed 100% identity with sequences from zinnia powdery mildew, forming a monophyletic clade with 100% bootstrap support, and with those of G. cichoracearum parasitic on the hosts belonging to the tribe Heliantheae of the family Asteraceae.

• 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.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.58-65
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• 2016

Powdery mildew is an important disease of the melon (Cucumis melo L.). Seven isolates of powdery mildew fungi were collected from five locations in Korea; Anseong (DH487), Icheon (BN103, BN625, BN968), Yeongam (YA141), Changnyeong (CN582), and Suncheon (SN102). All 7 fungi had a similar trend of conidial chain and conidiophore development as Podosphaera xanthii with fibrosin bodies in mature conidia. Among them, 2 isolates of powdery mildew fungi; CN582 and SN102 showed similar responses to resistance against powdery mildew as the previously reported race 1 and race N2. The isolates YA141 and BN103 showed similar responses as like as race A. However, three isolates of powdery mildew fungi (BN625, BN968, and DH487) showed different responses compared to the previously reported races (1, N1, N2, A, S, and 5). Therefore, these three isolates could be designated as new races in melon. Nine out of 15 commercial melon cultivars in Korea showed resistance to race 1 (CN582). However, the new race BN968 invaded all 15 cultivars. Results of the two molecular markers were consistent in response to disease development by race 1 of Podosphaera xanthii in case of the above mentioned cultivars. This study confirmed the presence of new melon powdery mildew fungi in Korea which are similarly notorious as like as the previously reported race 1. Therefore, breeders can use these two molecular markers for breeding melon in Korea that is resistant to race 1 and as well as to some other races.