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A Study on the Spatial Structure of Eupchi(邑治) and Landscape Architecture of Provincial Government Office(地方官衙) in the Late Joseon Dynasty through 'Sukchunjeahdo(宿踐諸衙圖)' - Focused on the Youngyuhyun Pyeongan Province and Sincheongun Hwanghae Province - (『숙천제아도(宿踐諸衙圖)』를 통해 본 조선시대 읍치(邑治)의 공간구조와 관아(官衙) 조경 - 평안도 영유현과 황해도 신천군을 중심으로 -)

  • Shin, Sang sup;Lee, Seung yoen
    • Korean Journal of Heritage: History & Science
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    • v.49 no.2
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    • pp.86-103
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    • 2016
  • 'Sukchunjeahdo' illustration-book, which was left by Han, Pil-gyo(韓弼敎 : 1807~1878)in the late Joseon Dynasty, includes pictorial record paintings containing government offices, Eupchi, and Feng Shui condition drawn by Gyehwa(界畵) method Sabangjeondomyobeop(四方顚倒描法) and is the rare historical material that help to understand spatial structure and landscape characteristics. Youngyuhyun(永柔縣) and Sincheongun(信川郡) town, the case sites of this study, show Feng Shui foundation structure and placement rules of government offices in the Joseon Period are applied such as 3Dan 1Myo(三壇一廟 : Sajikdan, Yeodan, Seonghwangdan, Hyanggyo), 3Mun 3Jo(三門三朝 : Oeah, Dongheon, Naeah) and Jeonjohuchim(前朝後寢) etc. by setting the upper and lower hierarchy of the north south central axis. The circulation system is the pattern that roads are segmented around the marketplace of the entrance of the town and the structure is that heading to the north along the internal way leads to the government office and going out to the main street leads to the major city. Baesanimsu(背山臨水 : Mountain in backward and water in front) foundation, back hill pine forest, intentionally created low mountains and town forest etc. showed landscape aesthetics well suited for the environmental comfort condition such as microclimate control, natural disaster prevention, psychological stability reflecting color constancy principle etc. and tower pavilions were built throughout the scenic spot, reflecting life philosophy and thoughts of contemporaries such as physical and mental discipline, satisfied at the reality of poverty, returning to nature etc. For government office landscape, shielding and buffer planting, landscape planting etc. were considered around Gaeksa(客舍), Dongheon(東軒), Naeah(內衙) backyard and deciduous tree s and flowering trees were cultivated as main species and in case of Gaeksa, tiled pavilions and pavilions topped with poke weed in tetragonal pond were introduced to Dongheon and Naeah and separate pavilions were built for the purpose of physical and mental discipline and military training such as archery. Back hill pine tree forest formed back landscape and zelkova, pear trees, willow trees, old pine trees, lotus, flowering trees etc. were cultivated as gardening trees and Feng-Shui forest with willow trees as its main species was created for landscape and practical purposes. On the other hand, various cultural landscape elements etc. were introduced such as pavilions, pond serving as fire protection water(square and circle), stone pagoda and stone Buddha, fountains and wells, monument houses, flagpoles etc. In case of Sincheongun town forest(邑藪), Manhagwan(挽河觀), Moonmujeong(文武井), Sangjangdae(上場岱) and Hajangdae(下場岱) Market place, Josanshup<(造山藪 : Dongseojanglim(東西長林)>, Namcheon(南川) etc. were combined and community cultural park with the nature of modern urban park was operated. In this context, government office landscape shows the garden management aspect where square pond and pavilions, flowering trees are harmonized around side pavilion and backyard. Also, environmental design technique not biased to aesthetics and ideological moral philosophy and comprehensively considering functionality (shielding and fire prevention, microclimate control, etc.) and environmental soundness etc. is working.

A Study of Dohang-Ri wooden coffin and Anya-Kuk (도항리목관묘(道項里木棺墓) 안사국(安邪國))

  • Lee, Ju-Huen
    • Korean Journal of Heritage: History & Science
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    • v.37
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    • pp.5-37
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    • 2004
  • A wooden coffin has been given academic attention in Kaya(伽倻), due to the place the stage of Samhan society appropriately in the development of ancient korea history. Special attention must be paid on Dohang-Ri(道項里) woden coffin, since it is expected to explain the origin of Arakaya(阿羅伽倻) in the region of southen korea peninsula. Dohang-Ri wooden coffin is become generally knowen two types, and complete its unique feature in Chin-Han(辰韓) and Byun-Han(弁韓). Recently the fact that Dohang-Ri wooden coffin is discovered only in the king tombs of Chang Won Daho-Ri(昌原茶戶里) and it is remarkable of political connection between Kuya-Kuk (狗邪國) and Anya-Kuk(安邪國). Various ironware unearth of Dohang-Ri has seen similar to that from Daho-Ri, but it has not bronze mirror be maid Chines, symbol with dignity of social position in the ruling ciass. It seems that political unit of Daho-Ri is advanced sociaity and central force than Dohang-Ri in the Byun-Han. The later of two century, I have a think about wooden coffin changes the wooden chamble of Dohang-Ri and Daho-Ri that it go out of sight at AD.2 century. Becouse of possitive achaelogical sites has not confirm, it request radical interpretaion. I inference to accordingly to the it appearance connected of the wars between the eight country of southen regins in korea peninsula at the first half of AD.3 cencury. Exactly, the politial units of Dohang-Ri and Daho-Ri has concentration of trade in Racdong river(洛東江) and Nam river(南江) water system and that give form to coexistence system of economic and political mutuality.

North Korea's Overseas Transfer Dance - Focusing on Japan and China - (북한춤의 해외전파 : 일본과 중국을 중심으로)

  • Kim, Chae-Won
    • (The) Research of the performance art and culture
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    • no.22
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    • pp.185-221
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    • 2011
  • This study overseas compatriots in the North during the propagation and development of dance patterns and was going to be based, people living outside of the dance culture as a group of overseas Koreans, especially dance culture of Koreans in Japan, China are interested in and thought about the necessity of the study. Issues discussed in the literature of research results, autonomous community of Koreans in Japan ethnic Koreans and Chinese dance culture dance Choi Seung-hee starting point common was, two ethnic groups, directly or indirectly from the Choi Seung-hee learn to dance or have received specialized training to work, compiled by Choi Seung-hee Korea on the basis of basic dance training was learning the dance. In addition, specialized training and dance training institutions in the North Koreans in Japan Social Dance Group for the system, such as dance training in a separate place where talented people through the exhaust, to act in a professional troupes have maintained a system. In contrast, Chinese ethnic Koreans in Yanbian Autonomous University and Central University for Nationalities in the dance departments are stationed there, the transfer from the Joseon dance dance by educating gifted talents have been dispose, South Korea and similar aspects of the dance education system can be seen. Dance work based training and the tendency of Koreans in Japan in terms of social practice and dance in the North of basic training as basic training and specialized training, and work to represent the North korea's famous dance folk dance performances have been transmitted intact. In China, however, ethnic Koreans Choi Seung-hee compiled by borough basis and the work of the North korean dance training or specialized training received directly from her, she founded the dance student of Choi Seung-hee developed basic techniques of Chinese ethnic dance and ethnic Koreans in China, while receiving only Sewonaga dance training system as a deal on exchanges with the North Korean dance dancing free dance culture for creation peppered ethnic Koreans in China was formed. When passed down to the time, Koreans in Japan since the 1960s, society began to visit Pyongyang in the 1970s, subjected to a direct transfer, and education and through the 1990s, the North Koreans in Japan by inviting dancers and dance directly to basic training by getting education bukhanchum As can be seen in the spectacular aspects will have to reproduce. However, ethnic Koreans in China in the 1950s in districts in Beijing, Pyongyang and received direct guidance from Choi Seung-hee, Dancers from the North after Pyongyang rather than direct guidance on the occasion of his visit to China Dance Troupe was affected. On the other hand Korean dance since the 1990s, starting with Ethnic Koreans in China only began to absorb a different dance culture has been created. The same nation, yet living in the region and to configure the ethnic groups, the configuration of the system and political system, according to the North Dancing transfer process and the development pattern similar, but each of the identities to ensure their own traits with a dance culture, the formation and develop the arrival of You can find out. In other words, Koreans in Japan and Federation of Koreans in Japan under the control of social forces of the dance culture by Acculturation variation of dance culture, dance culture of the borough ethnic Koreans in China Acculturation by the voluntary and free borrowers were able to gauge the changes in development.

Ecological Changes of Insect-damaged Pinus densiflora Stands in the Southern Temperate Forest Zone of Korea (I) (솔잎혹파리 피해적송림(被害赤松林)의 생태학적(生態学的) 연구(研究) (I))

  • Yim, Kyong Bin;Lee, Kyong Jae;Kim, Yong Shik
    • Journal of Korean Society of Forest Science
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    • v.52 no.1
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    • pp.58-71
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    • 1981
  • Thecodiplosis japonesis is sweeping the Pinus densiflora forests from south-west to north-east direction, destroying almost all the aged large trees as well as even the young ones. The front line of infestation is moving slowly but ceaselessly norhwards as a long bottle front. Estimation is that more than 40 percent of the area of P. densiflora forest has been damaged already, however some individuals could escapes from the damage and contribute to restore the site to the previous vegetation composition. When the stands were attacked by this insect, the drastic openings of the upper story of tree canopy formed by exclusively P. densiflora are usually resulted and some environmental factors such as light, temperature, litter accumulation, soil moisture and offers were naturally modified. With these changes after insect invasion, as the time passes, phytosociologic changes of the vegetation are gradually proceeding. If we select the forest according to four categories concerning the history of the insect outbreak, namely, non-attacked (healthy forest), recently damaged (the outbreak occured about 1-2 years ago), severely damaged (occured 5-6 years ago), damage prolonged (occured 10 years ago) and restored (occured about 20 years ago), any directional changes of vegetation composition could be traced these in line with four progressive stages. To elucidate these changes, three survey districts; (1) "Gongju" where the damage was severe and it was outbroken in 1977, (2) "Buyeo" where damage prolonged and (3) "Gochang" as restored, were set, (See Tab. 1). All these were located in the south temperate forest zone which was delimited mainly due to the temporature factor and generally accepted without any opposition at present. In view of temperature, the amount and distribution of precipitation and various soil factor, the overall homogeneity of environmental conditions between survey districts might be accepted. However this did not mean that small changes of edaphic and topographic conditions and microclimates can induce any alteration of vegetation patterns. Again four survey plots were set in each district and inter plot distance was 3 to 4 km. And again four subplots were set within a survey plot. The size of a subplot was $10m{\times}10m$ for woody vegetation and $5m{\times}5m$ for ground cover vegetation which was less than 2 m high. The nested quadrat method was adopted. In sampling survey plots, the followings were taken into account: (1) Natural growth having more than 80 percent of crown density of upper canopy and more than 5 hectares of area. (2) Was not affected by both natural and artificial disturbances such as fire and thinning operation for the past three decades. (3) Lower than 500 m of altitude (4) Less than 20 degrees of slope, and (5) Northerly sited aspect. An intensive vegetation survey was undertaken during the summer of 1980. The vegetation was devided into 3 categories for sampling; the upper layer (dominated mainly by the pine trees), the middle layer composed by oak species and other broad-leaved trees as well as the pine, and the ground layer or the lower layer (shrubby form of woody plants). In this study our survey was concentrated on woody species only. For the vegetation analysis, calculated were values of intensity, frequency, covers, relative importance, species diversity, dominance and similarity and dissimilasity index when importance values were calculated, different relative weights as score were arbitrarily given to each layer, i.e., 3 points for the upper layer, 2 for the middle layer and 1 for the ground layer. Then the formula becomes as follows; $$R.I.V.=\frac{3(IV\;upper\;L.)+2(IV.\;middle\;L.)+1(IV.\;ground\;L.)}{6}$$ The values of Similarity Index were calculated on the basis of the Relative Importance Value of trees (sum of relative density, frequency and cover). The formula used is; $$S.I.=\frac{2C}{S_1+S_2}{\times}100=\frac{2C}{100+100}{\times}100=C(%)$$ Where: C = The sum of the lower of the two quantitative values for species shared by the two communities. $S_1$ = The sum of all values for the first community. $S_2$ = The sum of all values for the second community. In Tab. 3, the species composition of each plot by layer and by district is presented. Without exception, the species formed the upper layer of stands was Pinus densiflora. As seen from the table, the relative cover (%), density (number of tree per $500m^2$), the range of height and diameter at brest height and cone bearing tendency were given. For the middle layer, Quercus spp. (Q. aliena, serrata, mongolica, accutissina and variabilis) and Pinus densiflora were dominating ones. Genus Rhodedendron and Lespedeza were abundant in ground vegetation, but some oaks were involved also. (1) Gongju district The total of woody species appeared in this district was 26 and relative importance value of Pinus densiflora for the upper layer was 79.1%, but in the middle layer, the R.I.V. for Quercus acctissima, Pinus densiflora, and Quercus aliena, were 22.8%, 18.7% and 10.0%, respectively, and in ground vegetation Q. mongolica 17.0%, Q. serrata 16.8% Corylus heterophylla 11.8%, and Q. dentata 11.3% in order. (2) Buyeo district. The number of species enumerated in this district was 36 and the R.I.V. of Pinus densiflora for the uppper layer was 100%. In the middle layer, the R.I.V. of Q. variabilis and Q. serrata were 8.6% and 8.5% respectively. In the ground vegetative 24 species were counted which had no more than 5% of R.I.V. The mean R.I.V. of P.densiflora ( totaling three layers ) and averaging four plots was 57.7% in contrast to 46.9% for Gongju district. (3) Gochang-district The total number of woody species was 23 and the mean R.I.V. of Pinus densiflora was 66.0% showing greater value than those for two former districts. The next high value was 6.5% for Q. serrata. As the time passes since insect outbreak, the mean R.I.V. of P. densiflora increased as the following order, 46.9%, 57.7% and 66%. This implies that P. densiflora was getting back to its original dominat state again. The pooled importance of Genus Quercus was decreasing with the increase of that for Pinus densiflora. This trend was contradict to the facts which were surveyed at Kyonggi-do area (the central temperate forest zone) reported previously (Yim et al, 1980). Among Genus Quercus, Quercus acutissina, warm-loving species, was more abundant in the southern temperature zone to which the present research is concerned than the central temperate zone. But vice-versa was true with Q. mongolica, a cold-loving one. The species which are not common between the present survey and the previous report are Corpinus cordata, Beltala davurica, Wisturia floribunda, Weigela subsessilis, Gleditsia japonica var. koraiensis, Acer pseudosieboldianum, Euonymus japonica var. macrophylla, Ribes mandshuricum, Pyrus calleryana var. faruiei, Tilia amurensis and Pyrus pyrifolia. In Figure 4 and Table 5, Maximum species diversity (maximum H'), Species diversity (H') and Eveness (J') were presented. The Similarity indices between districts were shown in Tab. 5. Seeing Fig. 6, showing two-dimensional ordination of polts on the basis of X and Y coordinates, Ai plots aggregate at the left site, Bi plots at lower site, and Ci plots at upper-right site. The increasing and decreasing patterns as to Relative Density and Relative Importance Value by genus or species were given in Fig. 7. Some of the patterns presented here are not consistent with the previously reported ones (Yim, et al, 1980). The present authors would like to attribute this fact that two distinct types of the insect attack, one is the short war type occuring in the south temperate forest zone, which means that insect attack went for a few years only, the other one is a long-drawn was type observed at the temperate forest zone in which the insect damage went on continuously for several years. These different behaviours of infestation might have resulted the different ways of vegetational change. Analysing the similarity indices between districts, the very convincing results come out that the value of dissimilarity index between A and B was 30%, 27% between B and C and 35% between A and C (Table 6). The range of similarity index was obtained from the calculation of every possible combinations of plots between two districts. Longer time isolation between communities has brought the higher value of dissimilarity index. The main components of ground vegetation, 10 to 20 years after insect outbreak, become to be consisted of mainly Genus Lespedeza and Rhododendron. Genus Quercus which relate to the top dorminant state for a while after insect attack was giving its place to Pinus densiflora. It was implied that, provided that the soil fertility, soil moisture and soil depth were good enough, Genus Quercuss had never been so easily taken ever by the resistant speeies like Pinus densiflora which forms the edaphic climax at vast areas of forest land. Usually they refer Quercus to the representative component of the undisturbed natural forest in the central part of this country.

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A Study on the Meaning and Strategy of Keyword Advertising Marketing

  • Park, Nam Goo
    • Journal of Distribution Science
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    • v.8 no.3
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    • pp.49-56
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    • 2010
  • At the initial stage of Internet advertising, banner advertising came into fashion. As the Internet developed into a central part of daily lives and the competition in the on-line advertising market was getting fierce, there was not enough space for banner advertising, which rushed to portal sites only. All these factors was responsible for an upsurge in advertising prices. Consequently, the high-cost and low-efficiency problems with banner advertising were raised, which led to an emergence of keyword advertising as a new type of Internet advertising to replace its predecessor. In the beginning of 2000s, when Internet advertising came to be activated, display advertisement including banner advertising dominated the Net. However, display advertising showed signs of gradual decline, and registered minus growth in the year 2009, whereas keyword advertising showed rapid growth and started to outdo display advertising as of the year 2005. Keyword advertising refers to the advertising technique that exposes relevant advertisements on the top of research sites when one searches for a keyword. Instead of exposing advertisements to unspecified individuals like banner advertising, keyword advertising, or targeted advertising technique, shows advertisements only when customers search for a desired keyword so that only highly prospective customers are given a chance to see them. In this context, it is also referred to as search advertising. It is regarded as more aggressive advertising with a high hit rate than previous advertising in that, instead of the seller discovering customers and running an advertisement for them like TV, radios or banner advertising, it exposes advertisements to visiting customers. Keyword advertising makes it possible for a company to seek publicity on line simply by making use of a single word and to achieve a maximum of efficiency at a minimum cost. The strong point of keyword advertising is that customers are allowed to directly contact the products in question through its more efficient advertising when compared to the advertisements of mass media such as TV and radio, etc. The weak point of keyword advertising is that a company should have its advertisement registered on each and every portal site and finds it hard to exercise substantial supervision over its advertisement, there being a possibility of its advertising expenses exceeding its profits. Keyword advertising severs as the most appropriate methods of advertising for the sales and publicity of small and medium enterprises which are in need of a maximum of advertising effect at a low advertising cost. At present, keyword advertising is divided into CPC advertising and CPM advertising. The former is known as the most efficient technique, which is also referred to as advertising based on the meter rate system; A company is supposed to pay for the number of clicks on a searched keyword which users have searched. This is representatively adopted by Overture, Google's Adwords, Naver's Clickchoice, and Daum's Clicks, etc. CPM advertising is dependent upon the flat rate payment system, making a company pay for its advertisement on the basis of the number of exposure, not on the basis of the number of clicks. This method fixes a price for advertisement on the basis of 1,000-time exposure, and is mainly adopted by Naver's Timechoice, Daum's Speciallink, and Nate's Speedup, etc, At present, the CPC method is most frequently adopted. The weak point of the CPC method is that advertising cost can rise through constant clicks from the same IP. If a company makes good use of strategies for maximizing the strong points of keyword advertising and complementing its weak points, it is highly likely to turn its visitors into prospective customers. Accordingly, an advertiser should make an analysis of customers' behavior and approach them in a variety of ways, trying hard to find out what they want. With this in mind, her or she has to put multiple keywords into use when running for ads. When he or she first runs an ad, he or she should first give priority to which keyword to select. The advertiser should consider how many individuals using a search engine will click the keyword in question and how much money he or she has to pay for the advertisement. As the popular keywords that the users of search engines are frequently using are expensive in terms of a unit cost per click, the advertisers without much money for advertising at the initial phrase should pay attention to detailed keywords suitable to their budget. Detailed keywords are also referred to as peripheral keywords or extension keywords, which can be called a combination of major keywords. Most keywords are in the form of texts. The biggest strong point of text-based advertising is that it looks like search results, causing little antipathy to it. But it fails to attract much attention because of the fact that most keyword advertising is in the form of texts. Image-embedded advertising is easy to notice due to images, but it is exposed on the lower part of a web page and regarded as an advertisement, which leads to a low click through rate. However, its strong point is that its prices are lower than those of text-based advertising. If a company owns a logo or a product that is easy enough for people to recognize, the company is well advised to make good use of image-embedded advertising so as to attract Internet users' attention. Advertisers should make an analysis of their logos and examine customers' responses based on the events of sites in question and the composition of products as a vehicle for monitoring their behavior in detail. Besides, keyword advertising allows them to analyze the advertising effects of exposed keywords through the analysis of logos. The logo analysis refers to a close analysis of the current situation of a site by making an analysis of information about visitors on the basis of the analysis of the number of visitors and page view, and that of cookie values. It is in the log files generated through each Web server that a user's IP, used pages, the time when he or she uses it, and cookie values are stored. The log files contain a huge amount of data. As it is almost impossible to make a direct analysis of these log files, one is supposed to make an analysis of them by using solutions for a log analysis. The generic information that can be extracted from tools for each logo analysis includes the number of viewing the total pages, the number of average page view per day, the number of basic page view, the number of page view per visit, the total number of hits, the number of average hits per day, the number of hits per visit, the number of visits, the number of average visits per day, the net number of visitors, average visitors per day, one-time visitors, visitors who have come more than twice, and average using hours, etc. These sites are deemed to be useful for utilizing data for the analysis of the situation and current status of rival companies as well as benchmarking. As keyword advertising exposes advertisements exclusively on search-result pages, competition among advertisers attempting to preoccupy popular keywords is very fierce. Some portal sites keep on giving priority to the existing advertisers, whereas others provide chances to purchase keywords in question to all the advertisers after the advertising contract is over. If an advertiser tries to rely on keywords sensitive to seasons and timeliness in case of sites providing priority to the established advertisers, he or she may as well make a purchase of a vacant place for advertising lest he or she should miss appropriate timing for advertising. However, Naver doesn't provide priority to the existing advertisers as far as all the keyword advertisements are concerned. In this case, one can preoccupy keywords if he or she enters into a contract after confirming the contract period for advertising. This study is designed to take a look at marketing for keyword advertising and to present effective strategies for keyword advertising marketing. At present, the Korean CPC advertising market is virtually monopolized by Overture. Its strong points are that Overture is based on the CPC charging model and that advertisements are registered on the top of the most representative portal sites in Korea. These advantages serve as the most appropriate medium for small and medium enterprises to use. However, the CPC method of Overture has its weak points, too. That is, the CPC method is not the only perfect advertising model among the search advertisements in the on-line market. So it is absolutely necessary that small and medium enterprises including independent shopping malls should complement the weaknesses of the CPC method and make good use of strategies for maximizing its strengths so as to increase their sales and to create a point of contact with customers.

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Studies on the Occurrence, Host Range, Transmission, and Control of Rice Stripe Disease in Korea (한국에서의 벼 줄무늬잎마름병의 발생, 피해, 기주범위, 전염 및 방제에 관한 연구)

  • Chung Bong Jo
    • Korean journal of applied entomology
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    • v.13 no.4 s.21
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    • pp.181-204
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    • 1974
  • The study has been carried out to investigate the occurrence, damage, host range, transmission and control of rice stripe virus in Korea since 1965. 1 Disease occur「once and damage : The virus infection during the seedling stage ranged from 1.3 to $8\%$. More symptom expression was found in regrowth of clipped rice than infected intact plants, and the greater infection took place in early seasonal culture than in ordinary seasonal culture. A higher incidence of the disease was found on the rows close to the bank, and gradually decreased toward the centre of the rice paddy. Disease occurrence and plant maturity was highly correlated in that the most japonica rice types were diseased when they were inoculated within 3 to 7 leaf stage, and$50\%$, $20\%$ and no diseaseb were found if they were inoculated at 9, 11 and 13 leaf stages, respectively. Symptom expression required 7-15 days when the plants were inoculated during 3-7 leaf stages, while it was 15-30days in the plants inoculated during 9-15 leaf stages. On Tongil variety the per cent disease was relatively higher when the plants were infected within 1.5-5 leaf stages than those at 9 leaf stage, and no disease was found on the plants infected after 15 leaf stage. The disease resulted in lowered growth rates, maturity and sterility of Tongil variety although the variety is known as tolerant to the virus. 2. Host range: Thirty five species of crops, pasture grasses and weeds were tested for their susceptibility to the virus. Twenty one out of 35 species tested were found to be susceptible. and 3 of them, Cyperus amuricus Maximowics var. laxus, Purcereus sanguinolentus Nees and Eriocaulon robustius Makino, were found as new hosts of the virus. 3. Transmission: The vector of the virus, Laodelphax striatellus, produces 5 generations a year. The peak of second generation adults occurred at June 20th and those of third was at about July 30th in Suweon area. In Jinju area the peak of second generation adult proceeded the peak at Suweon by 5-7 days. The peaak of third generation adult was higher than the second at Jinju, but at Suweon the reverse was true. The occurrence of viruliferous Laodelphax striatellus was 10-15, 9, 17, 8 and about $10\%$ from overwintered nymph, 1st generation nymph, 2nd generation adult, End generation nymph and the remaining generations, respectively. More viruliferous L. striatellus were found in the southern area than in the central area of Korea. The occurrence of viruliferous L. striatellus depended on the circumstances of the year. The per cent viruliferous vectors gin 2nd and 3rd generation adult, however, was consistantly higher than that of other generations. Matings of viruliferous L. striatellus resulted in $90\%$ viruliferous progenies, and the 3rd, 4th and 5th instars of the vector had higher infectiviey than the rest of the vector stages. The virus acquisition rate of non-viruliferous L. striatellus was $7-9\%$, These viruliferous L. striatellus, however, could not transmit the virus for more than 3 serial times. The optimum temperature for the transmission of the viru3 was $25-30^{\circ}C$, while rare transmission occurred when the temperature was below $15^{\circ}C$. The per cent of L. striatellus parasitization by Haplogonatopus atratus were $5-48\%$ during the period from June to the end of August, and the maximum parasitization was $32-48\%$ at around July 10. 4. Control: 1) Cultural practices; The deeper the depth of transplanting more the disease occurrence was found. The higher infection rate, $1.5-3.5\%$, was observed during the late stages of seedling beds, and the rate became lower, $1.0-2.0\%$, in the early period of paddy field in southern area. Early transplanting resulted in more infection than early seasonal culture, and the ordinary seasonal culture showed the lowest infection. The disease also was favored by earlier transplanting even under tile ordinary seasonal culture. The higher the nitrogen fertilizer level the more the disease occurrence was found in the paddy field. 2) Resistant varieties; Tongil varieties shelved the resistant reaction to the virus in greenhouse tests. In the tests for resistance on 955 varieties most japonica types shelved susceptible reactions, while the resistant varieties were found mostly from introduced varietal groups. 3) Chemical control; Earlier applications of chemicals, Disyston and Diazinon, showed better results when the test was made 4 days after inoculation in the greenhouse even though none of the insecticides shelved the complete control of the disease. Three serial applications of chemicals on June 14, June 20 and June 28 showed bettor results than one or two applications at any other dates under field conditions.

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