• Research in Plant Disease
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• v.19 no.4
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• pp.319-325
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• 2013

Soybean yellow mottle mosaic virus (SYMMV) and Soybean yellow common mosaic virus (SYCMV) were recently isolated in Korea, and it has not been reported how two viruses were dispersed in Korea. In 2012, we performed nationwide survey in subsistence soybean farming. Suspicious virus-infected infected leave were collected from the field and a total of 682 soybean tissue samples were assayed by RT-PCR using triplex primers detecting SYMMV, SYCMV, and Soybean mosaic virus (SMV). On hundred two samples showed SMV positive, and SYMMV and SYCMV were detected in 116 and 17 tissue samples, respectively. No sample showed double infection of SYMMV and SYCMV, but there were double infection tissues indicating two viruses positive of SMV plus SYMMV (5 tissue samples) and SMV plus SYCMV (1 tissue sample). Through this first subsistence soybean farming field survey, we assumed soybean viruses were originated from home seed production managed by farmer. Thus, in order to prevent possible seed transmission and further damage caused by virus transmission, virus-free commercial soybean seeds are recommended to be planted.

• Research in Plant Disease
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• v.10 no.4
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• pp.231-240
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• 2004

In the year of 2002 annual nationwide survey of virus diseases occurring in the pepper fields and greenhouses in Korea, the distribution and the incidence of viral diseases was investigated. The pepper samples from both greenhouses (155 samples) and open fields (227 samples) were collected and further analyzed to detect eleven different viruses by RT-PCR. The results indicate that no sample collected from both greenhouse and open field seems to be infected by TMV, RMV, PVY, AMV, and TSWV. On the other hand, CMV, BBWV2, PepMoV, PMMoV, TMGMV and ToMV are readily identified from greenhouse and open field samples by RT-PCR. The infection rates of the collected samples between greenhouse and open field are largely different. Comparing with 10% of virus-infected pepper samples grown in greenhouse, approximately one third of pepper samples collected from open field are infected. The mixed-infection rates in the virus-infected greenhouse and open field samples are 16% and 61%, respectively. The dominant virus occuring in greenhouse is PMMoV, indicating that virus-infected seed stocks and infected plant debris in the growing area may be important sources of inocula. On the other hand, both CMV and BBWV2 are dominant viruses in open field. This may indicate that the migration of viruliferous insect vectors into pepper fields may be the most important source of inoculum. Also, the survey shows that BBWV2 is newly immerging virus to be controlled in Korea. The discrepancies on the distribution and the occurrence of viral diseases between field and greenhouse may provide a fact that the accumulation and distribution of inoculum by successive cultivation and the migration of viruliferous vectors into growing areas are likely to be important factors to determine the incidence of viral diseases. Therefore, the further studies on epidemiology and the consideration of new breeding program of pepper are essential to minimize virus diseases.

• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.49-51
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• 1978

The 'take-all' disease of wheat was first reported in Korea in 1947. Ophiobolnis graunis was isolated again from wheat and barley in 1976 and 1977. In 1977, perithecia of Ophiobolus were found on stems of rice, wheat and corn. Perithecia were formed on recommend varieties of wheat in the greenhouse as a result of artificial inoculation of mycelia into the soil. During 1977, Take-all of wheat and barley was quite severe. The result of survey made during this showed about 5 percent that the disease was present in Suweon, Daejeon, Yesan and Yongin. The Take-all infection causes remarkable decrease in the average weight of the grain, followed by a reduction in the number of tillers per plant and amount of gram per ear.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.543-552
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• 2020

For efficient prevention and treatment of enteric colibacillosis, understanding about latest virulence factors and antimicrobial resistance of Escherichia coli is essentially needed. The aim of this study was to survey antimicrobial resistance and determine the prevalence of fimbriae and enterotoxin genes among 118 pathogenic E. coli isolates obtained from Korean pigs with diarrhea between 2016 and 2017. The genes for the toxins and adhesins were amplified by polymerase chain reaction (PCR). The susceptibility of the E. coli isolates to antimicrobials were tested using the standard Kirby-Bauer disk diffusion method. The most prevalent fimbrial antigen was F18 (40.7%), followed by F4 (16.9%), and the most prevalent combinations of toxin genes were Stx2e (21.2%), STb:EAST-1 (19.5%), and STa:STb (16.9%), respectively. Among the pathotypes, enterotoxigenic E. coli (ETEC) was the most predominant (67.8%), followed by Shiga-toxin producing E. coli (STEC, 23.7%). We confirmed high resistance rates to chloramphenicol (88.1%), tetracycline (86.4%), streptomycin (86.4%), and ampicillin (86.4%). And the majorities of isolates (90.7%) showed multi-drug resistance which means having resistance to 3 or more subclasses of antimicrobials. Results of this study can be a source of valuable data for investigating the epidemiology of and control measures for enteric colibacillosis in Korean piggeries.

• Proceedings of the Ginseng society Conference
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• 1987.06a
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• pp.89-107
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• 1987

For the elucidation of significance of saponin as quality criterion of ginseng ginsenoside content(GC) and ginsenoside pattern similarity(GPS) by simple correlation were investigated in relation to red ginseng quality factors, age, plant part, harvest season, mineral nutrition, soil physical characteristics, growth light and temperature, shading material, growth location, physiological disease and crop stand through survey of ginseng plantstions, field experiments, water culture and phytotron experiments. Effect of tissue culture was also reviewed. GC was negatively correlated with good quality of red ·ginseng and positively with bad quality. Age did not show any consistency with GC but GPS was less with the increase of age difference. GPS was less or not significant between taproot that is lowest in GC and epidermis highest, and significant between leaf and taproot. Harvest season marked with the lowest GC and Pattern was also different. Nutrient imbalance, the increase of hazardous soil nutrient and physical condition to growth increased GC, but GPS was little different. The higher the growth lights intensity and temperature the higher the GC but GPS was little changed. Root rust increased GC, but root scab decreased it. Sponge-like and inside cavity phenomena increased GC. Ginsenoside pattern of cultured tissues and rootlet showed great variation. These results strongly indicate that there are optimum saponin content and ginsenoside pattern and that these are accomplished under the optimum growth condition.

• Journal of the Korean Home Economics Association
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• v.47 no.8
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• pp.109-117
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• 2009

This study was conducted to investigate the uses of Aster scaber. The survey methodology employed was a questionnaire, which was used to interview 272 (37.8%) males and 448(62.2%) females from the Seoul and Kyunggido areas. The main results are as follows: 40-50 years old like and eat Aster scaber more frequently than 10-30 years old. The most popular reason provided for the preferance of Aster scaber was good health benefits. People indicating a dislike for Aster scaber had generally fewer previous experiences of eating this plant. Respondents who regularly ate healthy foods preferred prepared Aster scaber to others foods(p < .001). The main purchasing place was traditional markets and supermarkets. The main cooking method was boiling with addition of seasoning. Aster scaber was purported as having the following characteristics "low calories and thus great as diet food'(4.03), 'ability to prevent adult disease'(3.95), 'high in vitamins and minerals'(3.89), and 'high fiber content which prevented constipation'(3.85). However, it was not associated with 'astringent taste'(3.51) and was regarded as 'fat accumulation restrainer and remover of heavy metal'(3.53). Recognition and eating experience was low for Aster scaber kimchi and rice bread, bread, sauce and Aster scaber added health drinks. However opinion of its taste was regarded highly.

• Research in Plant Disease
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• v.22 no.4
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• pp.276-283
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• 2016

Bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa) occurred at 202 kiwifruit orchards for the survey period of 2013-2016, of which Psa biovar 2 (Psa2) and Psa biovar 3 (Psa3) were detected at 73 and 129 kiwifruit orchards, respectively. The number of kiwifruit orchards infected by Psa3 in 2016 increased nearly two times compared to 2015. Psa3 was detected from all the kiwifruit cultivars except some kiwiberry cultivars growing in Korea. Yellow-fleshed cultivars Hort16A and Jecy-gold and red-fleshed cultivar Hongyang were highly susceptible to Psa3. Our epidemiological and random amplification of polymorphic DNA analyses indicated that the first Psa3 incidence on Hongyang orchard in Sacheon, Gyoungnam might result from an introduction of Psa3-contaminated pollens from China for artificial pollination in 2014 and recent outbreaks of Psa3 in Sacheon and Goseong, Gyoungnam in 2016 might be due to rapid spread of bacterial canker by secondary infection of Psa3 from Hongyang orchard to neighboring Jecy-gold and Hayward orchards.

• Research in Plant Disease
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• v.18 no.4
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• pp.376-380
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• 2012

A survey of bacterial species associated with Korean isolates of pine wood nematode (PWN) was performed. A total of 110 bacterial isolates were obtained from the PWN isolates that were previously isolated from Pinus densiflora and P. koraiensis. Among the bacterial isolates, Cedecea neteri was most frequent (64 isolates) followed by Ewingella americana (21 isolates), Pseudomonas sp. (15 isolates), Flavobacterium sp. (8 isolates) and Rahnella aquatilis (2 isolates). Both E. americana and Pseudomonas sp. which are assumed to be closely associated with PWN were examined for their phytotoxicity to P. thunbergii seedlings. Ethyl acetate extracts of Psuedomonas sp. (Ba2 strain) cultures were found to induce wilting and mortality in the tested seedlings. The three bacterial species, Pseudomonas sp. (Ba2 strain), E. ameircana (Ba4 strain) and C. neteri (Ba10 strain) were examined in vitro for their sensitivity to 21 kinds of antibiotics. All of the strains were highly susceptible to carbenicillin, doxcycline and tetracycline.

• Research in Plant Disease
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• v.22 no.2
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• pp.65-71
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• 2016

Cymbidium mosaic virus (CymMV) is a major virus infecting orchid plants and causing economic loss. In this study, the incidence of viral infection in Calanthe spp. at the Korean Institute of Calanthe was investigated using reverse transcription polymerase chain reaction. The CymMV infection rate was 42%, and the two viruses Odontoglossum ringspot virus and Cucumber mosaic virus had frequencies of 8% and 2%, respectively. Additionally, we characterized an isolate of CymMV, CymMV-GW, using biological tests and examined the nucleotide sequence properties of its complete genome. CymMV-GW induced chlorotic ringspots and chlorotic spot symptoms in inoculated leaves of Chenopodium amaranticolor and Nicotiana benthamiana, respectively. In this study, we have for the first complete genome sequence of CymMV-GW in Korea. The CymMV-GW genome was 6,225 nucleotides in length, excluding the poly-(A) tail, and showed whole-genome nucleotide and amino acid sequence identities of 97.7% and 100%, respectively, with the NJ-1 isolate of CymMV. Here, we report the complete genome sequence of the CymMV-GW isolate and viral infection rates for Calanthe spp. in Korea.

• Research in Plant Disease
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• v.21 no.4
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• pp.346-350
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• 2015

To identify genome sequences of Apple scar skin viroid (ASSVd) isolates in Korea, the field survey was performed from 'Hongro' apple orchards located in eight sites in South Korea (Bongwha, Cheongsong, Dangjin, Gimchoen, Muju, Mungyeong, Suwon, and Yeongwol). ASSVd was detected by RT-PCR and PCR fragments were cloned into cloning vector. Full-length viral genomes of eight ASSVd isolates were sequenced and compared with 21 isolates reported previously from Korea, India, China, Japan and Greece. Eight isolates in this study showed 92.2-99.7% nucleotide sequence identities with those reported previously. Phylogenetic analysis showed that seven isolates reported in this study belong to the same group distinct from other groups.