• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.341-345
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• 1995

Seventy four microorganisms, which have antagonistic activity against to Fusarium culmorum, were tested for their inhibitory effect on colony development of obligate biotroph Erysiphe graminis f. sp. hordei Marchal, the causal agent of powdery mildew on barley plants. Of these, 13 actinomycetes isolates were shown to reduce the colony development of mildew completely by application of their 10% cell-free culture filtrates on barley leaves. An Isolate, A252, was the most powerful antagonist and its antifungal activity was further assessed. The colony development of mildew was significantly reduced by application of the 1% cell-free culture filtrate of isolate A252. In comparison to the control, the protective and curative application of 10% cell-free culture filtrate from A252 showed 88.5% and 96.1% reduction of colony numbers respectively. By the protective application, 68.3% of the inhibition was observed after 9 days of treatment, thus showed prolonged inhibitory effect. In vitro test, complete inhibition of the mycelial growth of Microdochium nivale was achieved by the treatment of 1% A252 culture filtrate and 80.2% of inhibition was observed by the 0.1% treatment.

• Mycobiology
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• v.32 no.3
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• pp.105-109
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• 2004

Erysiphe azaleae, a powdery mildew fungus on Rhododendron spp., was originally described from North America, and has only recently been recorded in Germany, England, Switzerland and Poland. The present paper records plentiful collections of this species from Poland, and provides additional information of its anamorphic state for taxonomic purposes.

• Landscaping Tree
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• v.57 no.7_8
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• pp.27-28
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• 2000

• The Korean Journal of Mycology
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• v.29 no.1
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• pp.75-78
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• 2001

The powdery mildew of Statice (Limonium shinuatum) extensively occurred in the experimental farm of Changwon Floricultural Experiment Station, Kyongsangnam-do Agricultural Research and Extension Services in 2000. Both sides of the leaves, petioles and stems were covered with the white fungal spores and mycelia, and then the leaves, petioles and stems became dark-colored, eventually died. The conidia and conidiophores formed on the lesion were observed. Conidia were cylindric to ellipsoid, $25.3{\sim}49.4{\times}12.3{\sim}7.2{\mu}m$ in size and borne singly on conidiophore. Fibrosin bodies were not observed. Conidiophores were stright with 2-4 cylindric cells, and $65.7{\sim}124.8{\mu}m$ in size. Appressorium was lobed type. Cleistothecia were not formed. This is the first report on powdery mildew of Statice (Limonium shinuatum) caused by Oidium sp. in Korea.

• The Plant Pathology Journal
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• v.34 no.3
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• pp.182-190
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• 2018

Powdery mildew caused by the obligate biotrophic fungus Podosphaera xanthii poses a serious threat to melon (Cucumis melo L.) production worldwide. Frequent occurrences of the disease in different regions of South Korea hints at the potential existence of several races which need to be identified. The races of five isolates collected from different powdery mildew affected regions were identified based on the pathogenicity tests of these isolates on eight known differential melon cultigens namely, SCNU1154, PMR 45, WMR 29, PMR 5, MR-1, PI124112, Edisto 47 and PI414723. None of the isolates have shown same disease responses to those of the known races tested in this study and in previous reports on these identical differential melon cultigens. This indicates that the tested uncharacterized isolates are new races. Among the isolates, the isolates from Hadong, Buyeo, Yeongam and Gokseong have shown same pathogenicity indicating the possibility of these isolates being one new race, for which we propose the name 'race KN1'. The isolate of Janghueng have also shown unique disease response in the tested differential melon cultigens and hence, we identified it as another new race with a proposed name 'race KN2'. Report of these new races will be helpful in taking effective control measures in prevalent regions and for future breeding programs aimed at developing varieties that are resistant to these race(s).

• Research in Plant Disease
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• v.12 no.1
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• pp.51-54
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• 2006

The effectiveness of four plant oils (garlic, ginger, cinnamon and lemongrass) against a range of plant pathogenic organisms was tested in vitro. Of the four oils, two oils (garlic and cinnamon) showed relatively good antimicrobial activities. Activity of garlic oil was shown against the plant pathogenic bacteria Agrobacterium tumefaciens, Ewinia carotovora, Ralstonia solanacearum, Xanthomonas campestris, and the fungi Phytophthora infestans, Fusarium oxysporum, Collectotricum sp., whereas Acidovorax avenae and Pythium sp. showed the resistance towards garlic oil. Results from the planta bioassays under greenhouse conditions indicated that garlic oil significantly reduced the cucumber powdery mildew (Sphaerotheca fusca) and tomato powdery mildew (Erysiphe cichoracearum) showing control value 70.0-74.6% and 71.2%, respectively.

• Research in Plant Disease
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• v.7 no.2
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• pp.120-122
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• 2001

The powdery mildew of broad bean (Vicia faba) extensively occurred in farmers' fields in Changseon-myon, Namhae-gun, Gyeongsangnam-do, Korea in 2001. Both sides of the leaves and stems were covered with white fungal spores and mycelia, and then the leaves and stems colored brown and dark brown and eventually died. Conidia and conidiophores were formed on the lesion. Conidia were cylindric, 29~45$\times$13~23 um (av, 36~18 um) in size and born singly on the conidiophore. Fibrosin bodies were not observed. Conidiophores were straight with 3-4 cylindric cells and 51~100$\times$6~10 um (av.70$\times$8 um) in size. Foot cell was 28~53$\times$7~10 um (av,39$\times$8 um) in size. Appressorium was a lobed type. Cleistothecia were not formed. This is the first report on powdery mildew of broad bean caused by Oidium sp. in Korea.

• The Korean Journal of Mycology
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• v.31 no.1
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• pp.50-52
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• 2003

The powdery mildew of Phlox (Phlox paniculata) extensively occurred in the experimental farm of Cheongam-myon, Hadong-gun, Gyeongnam province in 2002. Both sides of the leaves and stems were covered with the white fungal spores and mycelia, and then the leaves became brown to dark brown in color, eventually died. The conidiophores on the lesion were observed. Conidia were cylindric in shape, colorless, $25.3{\sim}49.4{\times}12.3{\sim}17.2{\mu}m$ in size and borne singly on conidiophore. Fibrosin bodies were not observed. Conidiophores were straight with 2-4 cylindric cells, and $65.7{\sim}124.8{\mu}m$ in size. Appressoria were lobed. Cleistothecia were not formed. This is the first report on powdery mildew of Phlox caused by Oidium sp. in Korea.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.337-343
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• 2020

During the extensive forays for discovering the biodiversity of phytopathogenic fungi in Korea, powdery mildew-affected purple coneflowers (Echinacea purpurea) were frequently found. Since 2004, nine samples have been deposited in the Korea University Herbarium. The initial symptoms include white, evanescent mycelia and irregular patches on mature leaves. Mild symptoms in the form of discolored lesions are also noticed on the stem and petal of the affected plants. Based on the morphological characteristics of the anamorph and the phylogenetic analysis of the internal transcribed spacers (ITS) and large subunit (LSU) rDNA sequences, the causal fungus was identified as Podosphaera xanthii. This is the first report that identifies the causal agent of powdery mildew disease affecting purple coneflower in Korea.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.695-703
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• 2014

We experimented with the effect of oleic acid and its appropriate concentration to prevent powdery mildew eco-friendly in a cucumber greenhouse cultivation. 'Baekbongdadaki' (Nongwoo Bio. co. Korea) was treated in the plastic greenhouse at Sangmyung University. We treated four levels of concentration of oleic acid, which were 0, 2000, 4000, 6000, and 8000 ppm. There were investigated diseased severity, diseased leaf area, control value, and pesticide injury. The degree of control values by oleic acid treatments was investigated at 3 days after treatment. The recurrence of powdery mildew was checked for 55 days. The day and night temperature in the greenhouse were controlled to 23 and $15^{\circ}C$ respectively. The humidity inside the greenhouse was not controlled to prevent outbreak of the disease. From the experimental results, oleic acid was very efficient to control powdery mildew. 2000 ppm of oleic acid was shown to be the most control efficiency without any pesticide injury. The recommended method to treat it was to spray three times every 3 weeks.