• Research in Plant Disease
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• v.14 no.3
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• pp.182-186
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• 2008

Recently organic farming practice of rice has been emerged in Korea, but one of the major limiting factor is the no effective environmental-friendly agro-materials to control major plant diseases. Bordeaux mixture has been used effectively as a preventive agro-chemical. The aim of this study was to investigate efficacy of Bordeanux mixture on control of rice blast caused by Magnaporthe grisea which is one of the disruptive rice diseases in world-wide. In greenhouse experiment, pre-treatment of 6-6 type of Bordeaux mixture before inoculation of spore suspension of M. grasea showed 71 % of control value. In field experiment, preventive applications of 4-8 and 6-6 types of Bordeaux mixture showed over 71 % of the control value. Chemical injury on rice leaves were not found in the application concentrations of all types of Bordeaux mixture, but observed in applications of Bordeaux mixtures between 30 and 100 diluted concentrations. This results indicate Bordeaux mixture can be used as an effective environmental-friendly agro-chemical to control rice blast disease in the field.

• Research in Plant Disease
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• v.14 no.3
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• pp.233-237
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• 2008

Tomato yellow leaf curl virus (TYLCV), a newly reported Geminivirus from tomato, generated recently large economic losses in Korea. Development of a fast and precise genetic diagnosis technique for detecting TYLCV which Agricultural research and extension services can utilize easy and handy is very important to prevent yield losses. Virion Capture (VC)/PCR is a simple, accurate and economical genetic detection method without any works or commercial kits for the extraction of the nucleic acid from the infected plants. Primers of twenty two for detection of TYLCV were designed and tested with extracted total DNA or crude sap from tomato leaf infected with TYLCV and healthy plant. Nine primers for total DNA using conventional PCR and another 9 primers for VC/PCR were selected eventually. Primers of six having same specificity were selected from the two methods and tested with other Geminivirus, Tobacco leaf curl virus (TLCV) by VC/PCR. Finally specific primers of four were selected for detection of TYLCV using VC/PCR, and Deng (540, 541), a degenerate primer for Geminivirus reported in 1996, was also developed for VC/PCR.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1731-1736
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• 2007

본 연구에서는 체가름 시험을 통해 얻은 대표입경으로 조도계수를 산정하고 그 산정된 조도계수의 효용을 검정하고자 하였다. 체가름 분석을 통해 입도곡선을 작성하고 대표입경을 구함으로서 기 수립된 공식에 의한 조도계수를 산정하였다. 산정된 조도계수는 HEC-HMS의 하도추적 방법 중에 하나인 Muskingum-Cunge 8 point 방법과 HEC-RAS의 부정류 해석을 이용한 방법으로 얻은 조도계수를 비교하였다. HEC-HMS의 경우 대상유역인 오산천 유역에 대해 선행연구과정으로 저수지 방류량을 고려한 강우-유출 모형의 매개변수 추정에 관한 연구가 이뤄졌다(2006, 이아름). 선행연구에서는 계산된 유량과 실측 유량을 비교하여 Clark 단위도 방법의 매개변수를 추정하여 그 중 빈도가 큰 유출사상의 경우에 Sabol 식에 의한 모의 결과가 첨두유량의 재현성이 우수하게 나타남을 확인했다. 따라서 HEC-HMS 모형은 Clark 단위도 방법의 매개변수는 Sabol의 식에 의해 모형을 구성하고 2001년, 2002년, 2004년, 2005년의 사상에 대해 강우량, 기흥 저수지와 이동저수지의 실제 방류량을 이용해 유출량을 산정하였다. 이중 오산천 유역에 대해 선행연구에서 사용된 Muskingum의 하도추적 방법은 Muskingum-Cunge 8 point 방법으로 변경하여 대상유역에서의 조도계수를 산정하였다. HEC-RAS 모형의 부정류 해석은 2002년과 2005년의 사상으로서 상류단 경계조건으로 기흥 저수지의 방류량을 유량수문곡선으로 이용하였고, 하류단 경계조건으로는 회화수위관측소의 수위수문곡선을 이용했다. 대표입경을 이용해 얻은 조도계수를 HEC-HMS, HEC-RAS를 통해 검정한 결과 실측된 유량과 수위를 비교적 잘 재현해 내는 것으로 나타났으나, 조도계수의 보정을 통한 재현 유량과 수위를 비교했을 때, 대표입경을 통해 얻은 조도계수가 보정 조도계수보다 다소 작은 것으로 해석되었다.하고자 한다.해결책을 얻어내는 상호보완적인 결과를 추구한다. 그가 디자인하는 작품은 전형적인 이미지를 내포하지 않는다. 즉 그의 작품은 기존의 가치와 이념적인 것은 배제하고, 창의적인 개념을 도출하였다.형모서리는 건물 특화 성격이 강하므로 불가피할 경우 소형 액센트 광고 위치를 미리 벽면으로 할애하는 것이 경관 및 입면계획에 유리한 것으로 분석되었다. 불확실도 해석모형 등의 새로운 기능을 추가하여 제시하였다. 모든 입출력자료는 프로젝트 단위별로 운영되어 data의 관리가 손쉽도록 하였으며 결과를 DB에 저장하여 다른 모형에서도 적용할 수 있도록 하였다. 그리고 HyGIS-HMS 및 HyGIS-RAS 모형에서 강우-유출-하도 수리해석-범람해석 등이 일괄되게 하나의 시스템 내에서 구현될 수 있도록 하였다. 따라서 HyGIS와 통합된 수리, 수문모형은 국내 하천 및 유역에 적합한 시스템으로서 향후 HydroInformatics 구현을 염두에 둔 특화된 국내 수자원 분야 소프트웨어의 개발에 기본 토대를 제공할 것으로 판단된다.았다. 또한 저자들의 임상병리학적 연구결과가 다른 문헌에서 보고된 소아 신증후군의 연구결과와 큰 차이를 보이지 않음을 알 수 있었다. 자극에 차이가 있지 않나 추측되며 이에 관한 추후 연구가 요망된다. 총대장통과시간의 단축은 결장 분절 모두에서 줄어들어 나타났으나 좌측결장 통과시간의 감소 및 이로 인한 이 부위의 통과시간 비율의 저하가 가장 주요하였다. 이러한 결과는 차가운 생수 섭취가 주로 결장 근위부를 자극하는 효과를 발휘하는 것이 아닌가 해석된다. 이와 같은 연구결과를 통해 생다시마를 주원료로 개발된 생다시마차와 생다시마 음료가 만성 기능성 변비 증세를 개선하는 효능이 잠재적으로 있음을 확인하였다. 그러나 생약제재의 변비약 수준으로 변비 개선 효능을 증대하기 위해서는 재료 배합비의 개선이나 대장 운동기능을 향상시키는 유효성분의 보강 등이 필요하다는 점도 알 수 있었다.더불어

• Research in Plant Disease
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• v.21 no.2
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• pp.99-102
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• 2015

Cucumber mosaic virus (CMV) is one of the most destructive viruses in chilli pepper. An isolate of CMV was obtained from the chilli pepper cv. Chungyang showing top necrosis symptom in 2013 and designated as CMV-GTN. CMV-GTN was compared with the well-characterized isolate, CMV-Ca-P1, by investigating their amino acid sequences of the coat protein (CP) and biological reactions in several host plants. The CP of CMV-Ca-P1 composed of 217 amino acids but that of CMV-GTN composed of 218 amino acids by including additional valine in the $57^{th}$ amino acid position. Amino acid sequence similarity of the CP gene among CMV-GTN and other CMV isolates recorded in the GeneBank database ranged from 96% to 99%. CMV-GTN was selected as a representative isolate to screen the resistance pepper cultivars to CMV because it was highly pathogenic to tomatoes and peppers upon biological assays. The virulence of CMV-GTN was tested on 135 pepper cultivars which has been bred in Korea and compared with that of CMV-Ca-P1. Only the cv. Premium was resistant and three cvs. Hot star, Kaiser, and Good choice were moderately resistant to CMV-GTN, whereas two cvs. Baerotta and Kaiser were resistant to CMV-Ca-P1.

• Research in Plant Disease
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• v.18 no.1
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• pp.10-16
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• 2012

This study was conducted to examine the effects of the seeding rate on the disease incidence of sharp eyespot(Rhizoctonia cerealis) on three different varieties and to select effective chemicals to control the disease. When the seeds were sown twice as many as the recommendation, the disease incidence increased by approximately 13%. However, the susceptible variety 'Jopummil' alone showed the significantly enhanced disease incidence at a two-fold seeding rate. Two chemicals such as Hexaconazole EC and Tebuconazole EC highly inhibited the fungal growth on agar medium. However, two strobilurin fungicides such as Pyraclostrobin EC and Trifloxystrobin SC were relatively weak. The fungicides tested displayed the similar in vivo antifungal activities as in vitro activities. Hexaconazole EC and Tebuconazole EC showed the strongest both protective and curative activities and the protective activities of the chemicals were generally higher than the curative activities. Hexaconazole EC and Tebuconazole EC controlled the disease by 64% and 73%, respectively, and the two chemicals reduced the disease by 45% and 39%, respectively, when they were applied one day after pathogen inoculation. These results indicate that both Hexaconazole EC and Tebuconazole EC could be used to control sharp eyespot on wheat.

• Research in Plant Disease
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• v.14 no.1
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• pp.43-50
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• 2008

Rhizoctonia blight (large patch) caused by Rhizoctonia solani AG2-2 is one of the major diseases on zoysiagrass in golf courses. In this study, anatgonistic bacteria to R. solani AG2-2 were selected in vitro tests using confrontation bioassay and triple layer agar diffusion method. The most active bacteria, Bacillus subtilis CJ-9 were tested for controlling large patch in pots. Relative Performance Indies (RPI) was used as a criterion for the selection of potential biocontrol agent. B. subtilis CJ-9 showed resistance to major synthetic agrochemicals used in golf course. In field tests at golf course, B. subtilis CJ-9 was more effective in suppression of large patch severity and population development of R. solani AG2-2 in soil than chemical fungicides. B. subtilis CJ-9 could be an alternative to chemical fungicides for eco-friendly management of large patch on zoysiagrass.

• Research in Plant Disease
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• v.12 no.2
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• pp.144-147
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• 2006

Egg yolk immunoglobulin (IgY) is much widely used in medical fields, but its use in serology of plant viruses is much limited. We produced an IgY against pepper mild mottle virus (PMMoV) and applied it to several serological tests. Polyclonal antibodies were obtained from the egg yolk of chicken immunized with a total of 2mg of purified PMMoV over 2 months. The titers of antibodies were measured with the ring-test over six months after the first injection. The highest.titers of IgY was 1/2,560 at 2 months after the first injection. Approximately 60-80 mg of IgY were obtained from one egg yolk. Using the IgY, 1ng/ml of purified PMMoV was detected with the indirect ELISA. Gelrite gel double diffusion test, ELISA and tissue immuno-binding assay employing IgY gave similar sensitivity and specificity to those of IgG developed in rabbit. Therefore, the IgY which can be obtained in large quantities from a chicken, might be useful for the antibody production and the serology of plant viruses.

• Research in Plant Disease
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• v.26 no.4
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• pp.256-263
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• 2020

Incidence of Fusarium wilt was surveyed in fields of summer radish in Gangwon province in Korea in 2018 and 2019. The disease started in early July and spread rapidly in hot summer of late July and August and in severe case, reached up to 80% in a field in Gangneung area. Symptoms in the seedling stage include poor growth and browning of internal tissue of root. During mid-growth, the leaves of diseased plant turned yellow over time, the surface of the roots changed from white to blackish, and the vascular tissues turned brown. A total of 23 isolates was obtained from the diseased plants and identified as Fusarium oxysporum f. sp. raphani by elongation factor-1α and intergenic spacer sequence analysis. Pathogenicity of the isolates was tested by artificial inoculation to the radish and other plants. All the isolates tested were pathogenic to radish plant, although there were differences in virulence on radish 11 cultivars. However, the isolates were not virulent to other plants except some cruciferous vegetables including Brussels sprouts, rocket, stock, and turnip. The results of pathogenicity test showed that it is necessary to rotate with crops other than cruciferous vegetables in order to prevent Fusarium wilt from radish fields.

• Research in Plant Disease
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• v.29 no.1
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• pp.88-93
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• 2023

To investigate the incidence status of viruses in major cultivated areas of watermelon and melon in Chungbuk Province, samples were collected from 2020 to 2021 in vinyl greenhouse of Jincheon and Eumseong and examined for virus infection using reverse transcription polymerase chain reaction. Of the six viruses on watermelon that was analyzed in this study, watermelons were infected with cucumber mosaic virus (CMV), watermelon mosaic virus (WMV), cucumber green mottle mosaic virus (CGMMV), and cucurbit aphid-borne yellows virus (CABYV). The incidence rate of CMV was 20.9-35.0%, WMV 0.4-15.8%, CGMMV 1.6-38.5%, and CABYV was 3.5-3.7% from 2020 to 2021. But strangely, there were no incidence of zucchini yellow mosaic virus and cucurbit chlorotic yellows virus (CCYV) during investigation. From this result, we knew the major virus was CGMMV on watermelon in Chungbuk Province. Molecular diagnosis assays of the two melon viruses, showed that melons were infected with CABYV and CCYV from 2020 to 2021. The incidence rate of CABYV was 53.9-92.2% and CCYV was 2.7-20.8%. The incidence of CABYV was high in melon cultivation of Jincheon and Eumseong, Chungbuk. Afterwards, it is necessary to establish a control management strategy for reduce the incidence of CABYV. Furthermore, we must pay attention that of CCYV even if the incidence was low.

• Research in Plant Disease
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• v.29 no.1
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• pp.79-81
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• 2023

During the nationwide survey of fire blight, the typical shoot blight symptoms were found on Korean mountain ash (Sorbus alnifolia) which was located near an orchard that produced fire blight on pear trees in Eumseong, Korea, May 2021. To identify the causal agent, we progressed isolation from the symptomatic leaves and shoots. Two white and mucoid colonies were isolated into the pure culture. Two isolates were identified as Erwinia amylovora according to the colony-polymerase chain reaction (PCR) with amsB primers and the phylogenetic tree using 16S rRNA sequences. To test of pathogenicity of two isolates, we inoculated immature pear fruits and understock of apple. We observed necrosis and oozes on immature pear fruits and shoot blight resulting in necrosis on apple shoots six days after inoculation. Colonies were recovered from the inoculated pears and apples, and identity was confirmed through colony PCR for amsB genes. To our knowledge, E. amylovora was first reported on Korean mountain ash native to South Korea.