• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.85-94
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• 2005

A fungal isolate was newly collected from Zoysiagrass 'Anyang-Joongji' in small circular patches on a fairway ofa golf course in Korea, which seriously occurred during the early summer period of 2005. The isolate presented on PDAmedium, named Scz1, was closely identical to Sclerotinia homoeocarpa, a casual fungus of dollar spot disease, in cool season turf grasses such as creeping bentgrass. Hereby, this study was accomplished to characterize the isolate and compare it with the fungus, named Scb1, isolated from dollar spot-infected creeping bentgrass (Agrostis palustris Huds. cv Penncross). On PDAmedium, individual mycelial appearance of three isolates was very similar except for the pigment. Mycelial pigments of Scz1 and Scz2 (another analogous isolate collected) were light pinkish on the reverse side of PDA medium but that of Scb1 was dark brownish. In a microscopic study, three isolates were barely distinguishable in the appearance of mycelia. As expected, in the temperaturesensitivity assay, all pathogens were very delicate to $32^{circ}C$ above but not to $30^{circ}C$ below, in which was explained to be one of typical characteristics in S. homoeocarpa. In an artificial inoculation assay, disease symptoms including leaf spots in Zoysiagrass were appeared within 6-7 days after inoculation through the hand inoculation method with the isolate-infested soil. Then the fungus was re-identified from the infected leaf tissues. Interestingly, inoculation of isolate Scz1 gave rise to distinct symptoms in only Zoysiagrass but not in creeping bentgrass 'Penncross' and Kentucky bluegrass 'Midnight'. The observation might be involved in host specific pathogenecity of S. homoeocarpa Scz1 to Zoysiagrass. In a chemical sensitivity assay for the isolate, Scz1, showed a high mycelial inhibition against two fungicides, iprodione and propiconazole. All results described above suggest that S. homoeocarpa Scz1 is a primary pathogen of Zoysia dollar spot disease.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.86-91
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• 1995

Isolation and pathogenicity of Fusarium spp. from mulberry shoot rot and severity of diseases which were known as bacterial blight were examined on four mulberry varieties in Suwon, Kongju and Chuncheon, A symptom of mulberry shoot rot was initiated long brown spot on young leaves and shoots. It was developed into dark brown spot and produced white mycelia and spores on the diseased symptoms. A symptom of bacterial blight showed leaf rolling and water soaking spot and produced bacterial ooze on leaf and shoot However later stage of upper two types of symptom was hardly distinguished. Severities of shoot rot and bacterial blight were 7.5% and 4.4% in Suwon, respectively. Isolation of Fusarium spp. on shoot rot symptoms was highter than that on bacterial blight symptoms, but isolation of Pseudomonas spp. was higher on bacterial blight symptoms. Trends of pathogenicity of Fusarium spp. and Pseudomonas spp. were similar to inoculation works, and isolations of pathogenic Fusarium spp. from center of symptom was higher than that from 30cm of symptom of all samples in three cultivation areas. Disease severities of shoot rot on variety of Kaeryangppong were 13.9%, 15.9% and 17.2% in Suwon, Kongju and Chuncheon, respectively. However variety of Cheongolppong was highly resistant to shoot rot disease in three cultivation areas.

• Research in Plant Disease
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• v.19 no.4
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• pp.300-307
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• 2013

This study was conducted to determine the occurrence of leaf rot and leaf ring spot, caused by Rhizoctonia solani in Chinese cabbage under seedling nursery and cultivation greenhouses. Symptoms of leaf rot and leaf ring spot were found in three Chinese cabbage cultivars, Brassica campestris subsp. pekinensis, 'Ryeokgwang', 'Daetong', and 'CR mat'. In Hwacheon, the disease incidence was 73.8% in the seedling stage of the Chinese cabbage. In Icheon, the symptoms were observed on the upper leaves of the Chinese cabbage cultivar, 'Norangmini' with 20.5% of disease incidence. The symptoms appeared as primary lesions consisting of small, circular necrotic ring spots with gray color, 1.4-3.0 mm in diameter, accompanied by secondary rot lesions with large irregular borders of leaves. The color of mycelial mat of 20 isolates was dark brown and light brown. The average hyphal diameter of all the isolates was within 5.01-11.12 ${\mu}m$. Among the 20 strains isolated from Chinese cabbage, 16 isolates and four isolates anastomosed with the AG-1 (IB) and AG-1 (IC), respectively. Twenty isolates tested were only virulent on foliage parts of Chinese cabbage leaves but were avirulent on stem parts of the plants. Based on the mycological characteristics and pathogenicity test on host plants, the fungus was identified as Rhizoctonia solani.

• Research in Plant Disease
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• v.10 no.2
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• pp.112-116
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• 2004

This study was carried out to investigate factors affecting disease development of rice brown spot caused by Cochliobolus miyabeanus in the field and under the greenhouse conditions. In normal paddy fields, the pathogen was more frequently isolated from dried rice straws than wet straws after overwintering. The pathogen was also readily isolated from wet rice straws of salty paddy fields although infection rate of the fields was low. The disease symptom was first observed at 2 to 3days after inoculation when the seedlings were kept for 6 hours in dew chamber. The number of lesions peaked at 14 hr incubation in cultivars Chucheongbyeo and 24 hr incubation in cultivar Daesanbyeo and Tetep. Sixty three-d-old seedlings were more susceptible than 21 to 49-d-old seedlings regardless of cultivar. There was some difference in number of lesions observed, but the lesions were evenly spread regardless of leaf position. Light on the rice seedlings at 3,000 lux or 6,000 lux showed more severe symptoms than those in the dark.

• Parasites, Hosts and Diseases
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• v.51 no.1
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• pp.125-128
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• 2013

In April 2010, pruritic symptoms were recognized in 3 privately-owned Siamese cats raised in Gwangju, Korea. Examination of ear canals revealed dark brown, ceruminous otic exudates that contain numerous live mites at various developmental stages. Based on morphological characteristics of adult mites in which caruncles were present on legs 1 and 2 in adult females and on legs 1, 2, 3, and 4 in adult males while the tarsus of leg 3 in both sexes was equipped with 2 long setae, the mite was identified as Otodectes cynotis. Ten ear mite-free domestic shorthaired cats were experimentally infected with O. cynotis to evaluate the efficacy of 10% imidacloprid/1% moxidectin spot-on. Live mites were recovered from 1 of 10 treated cats on day 9 post-treatment (PT) while no live mites were observed from the ear canals of treated cats on days 16 and 30 PT. The efficacy of 10% imidacloprid/1% moxidectin spot-on on O. cynotis in cats was, therefore, 90% on day 9 and 100% on days 16 and 30 PT. This is the first report of otodectosis in 3 cats naturally infested with O. cynotis in Gwang-ju, Korea. Both natural and experimental infestations were successfully treated with 10% imidacloprid/1% moxidectin spot-on.

• Research in Plant Disease
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• v.16 no.1
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• pp.86-89
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• 2010

Brown leaf spot caused by Phyllosticta cruenta from 2007 to 2009 occurred severely in an herbs exhibition on Doonggulle (Polygonatum odoratum) at Gangju pond in Jeongchon-myon, Jinju city, Gyeongnam province, Korea. The typical symptoms of this disease were appeared on the brown leaf spot of leaves. Lesions on the leaves were appeared elliptical or irregular with 2~8 mm in size. Infected leaves were wilted, blighted and eventually died. Pycnidiospores and pycnidia of the fungus were abundantly formed on PDA. The optimum temperature for mycelial growth was $20{\sim}{25^{\circ}C}$. Pycnidiospores were not readily formed on PDA, colorless in color, globose~subglobose in shape, $10{\sim}18{\times}5{\sim}12{\mu}m$ in size and appendage hanged $4{\sim}15{\mu}m$ in size. Pycnidia were globose~subglobose in shape, dark brown in color and $60{\sim}162{\times}70{\sim}174{\mu}m$ in size. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Phyllosticta cruenta (Kunze: Fries) Kickx. This is the first report on the brown leaf spot of Doonggulle caused by P. cruenta in Korea.

• Research in Plant Disease
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• v.13 no.2
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• pp.122-125
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• 2007

Leaf spot disease of Kalanchoe (Kalanchoe blossfeldiana) occurred at the farmer's vinly house in Gangseo-gu, Busan Metropolitan City, Korea, 2006. The diseased plants with typical symptom were collected and the casual agent were isolated. Its mycological characteristics and pathogenicity were examined. The results were as follows. The typical symptoms of the disease appeared as small brownish or dark brown spot on both sides of the leaves. The spots tended to develop from lower leaves. The spots gradually enlarged into conspicuous necrotic lesions 1-5 mm in diameter. Colonies of the causal fungus formed on potato dextrose agar were velvety, gray or grayish brown in color, Conidia were cylindrical or obclavate to oblong in shape, brown in color, $24{\sim}65\;{\times}\;12{\sim}23\;{\mu}m$ in size and had 1-4 transverse septa, The optimum temperature for growth of the fungus was about $25-30^{\circ}C$. Conidiophores were brown in color, $32{\sim}135\;{\times}\;4{\sim}8\;{\mu}m$ in size and had 1-7 transverse septa. The fungus was identified as Stemphylium lycopersici (Enjoji) Yamamoto based on its symptom and mycological characteristics. This is the first report of leaf spot of Kalanchoe caused by S. lycopersici in Korea.

• Research in Plant Disease
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• v.21 no.3
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• pp.243-249
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• 2015

Soybean frogeye leaf spot caused by the fungus Cercospora sojina Hara, has known to lead a severe reduction of crop yield. Since frogeye leaf spot on soybean has recently become a serious problem in Korea, the susceptibility of recent recommended cultivars against C. sojina had been tested. To standardize the disease severity of soybean, the optimum sporulation condition of C. sojina and the disease index were established in this study. Sporulation was maximized on the 10% V8 juice agar with 12 h light and 12 h dark at $25^{\circ}C$. Spore suspension ($10^5spores/ml$) was sprayed on the leaves of soybean (V6 stage), and the disease responses to each isolate were evaluated on 28 days after inoculation. As a result, Daepung, Shinpaldal2ho, Yeonpung and Cheonga showed the resistance reaction to 8, 7, 6, 6 isolates of C. sojina, respectively, whereas Cheongja, Hwangkeum, Taekwang, Daewon, Cheonsang and Sinhwa showed the susceptible reaction to 8 isolates of C. sojina. Breeding the resistant soybean cultivars against C. sojina requires a uniform resistance for screening technique. The disease index of frogeye leaf spot on soybean developed in this study can be effectively used for the accurate field assay to select the frogeye leaf spot resistant soybean.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1567-1569
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• 2004

유기발광 소자의 전공 수송층 재료로 많이 쓰이고 있는 N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-biphenyl-4-4'-diamine(TPD)는 OLED소자가 연속적으로 작동하게 되면 TPD박막이 결정화되는데, 이러한 결정화는 디스플래이 소자에 dark spot(흑점)의 문제점을 가져왔다. 이러한 원인을 제거하기 위해서 ITO위에 PolyThiophene을 완충층으로 제작함으로써, OLED 소자의 효율에 미치는 영향은 크다고 할수 있다. 자체 제작한 플라즈마 중합장치의 중합조건과 중합체 PolyThiophene의 분자구조를 알아보았다.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.1
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• pp.78-80
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• 1993

Of the forma of Hibiscus Syriacus, national flower, a dozens of them have been recommended for landscape treess. To find out the highly resistant forma, 13 forma of Shrub al thea were fumigatedqr with $SO_2$ in phytotron and their visible injury was observed. Visible injury of Shrub al thea forma was spread on the vein in the shape of spot and diffused to whole leaf with wilting. The injury colors of forma were generally dull bluish green, dark grayish green. The tolerant forma to $SO_2$ were Sanchunyeo, Saeachim, Sulag and the highly sensitive forma were Lusi, Youngkwang. Therefore, Sanchunyeo, Saeachim and Sulag were recommeneded to plant in polluted areas.