• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.13 no.2 s.107
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• pp.76-83
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• 1992

호박은 비교적 병해가 적은 작물로 알려지고 있지만 사실은 호박의 재배면적이 일반화되지 않아서 그런 느낌이 들 뿐이지 시설재배단지에서는 어느 작물 못지 않게 병해의 발생이 심하다. 우리나라에서 호박에 발생하는 병해는 모두 12가지가 알려지고 있다. 그러나 호박재배에서 가장 큰 골칫거리 병해는 흰가루병, 노균병, 잿빛곰팡이병, 균핵병, 검은별무늬병, 세균성반점병, 바이러스병등 수종에 불과하다. 이외에 역병, 덩굴마름병, 탄저병, 무름병등이 발생하고 있으나 위에 열거한 병에 비하여 일반적이지 못하며 피해도 크지 않다.

• Korean journal of applied entomology
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• v.19 no.1 s.42
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• pp.51-55
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• 1980

The study has been carried to confirm pathogenesity among the isolates which obtained from leaf blight type symptoms and Kresek type symptoms, and also to observe varietal resistance among 29 varieties and/or lines through the introduction of two different pathotypes, of Xanthomonas oryzae, by the use of root clipping and pin prick methods. There was no significant differences among the isolates when their growth in plant tissue were compared. There was certain tendency, however, that the isolates from Kreseked plants showed longer lesion than those from blight type lesions. Both isolates from blight type and Kresek type induced the same degree of Kresek syptoms when they were introduced into plants by root cutting in the suspension prior to transplant. Varietal resistance to 'Kresek' appeared to be the same with those on leaf blight type though Wase Aikoku group varieties showed Kresek symptoms which is not the case with leaf blight type. IR 20 in Kogyoku group varieties showed highly resistant reaction to Kresek type. Root clipping method induced the more of Kresek than those by pin pricking method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.132-136
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• 1990

This experiment was conducted to study the multiplication and spread of bacterial population in water exuded through the hydathode of infected leaf of Xanthomonas campestris pv. oryzae in resistant and susceptible rice cultivars to bacterial leaf blight. The results obtained are summarized as follows. The bacterial multiplication in resistant cultivars was almost constant from three days to twelve days after inoculation with population of 10$^3$-10$^4$cfu/$\textrm{cm}^2$, but the multiplication was increased as days after inoculation extended in susceptible cultivars. The speed of bacterial multiplication and the number of bacteria spread above and below the inoculated position were closely related with the resistance of rice cultivars to bacterial leaf blight. The bacterial multiplication and spread were observed throughout the all growing stages including seedling, maximum tillering and flag leaf stages. The bacterial populations in water exuded through the hydathode were dependent on the multiplication and spread, and the populations were also closely related with the resistance of rice cultivars.

• Journal of Sericultural and Entomological Science
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• v.46 no.1
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• pp.12-17
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• 2004

New triploid mulberry cultivar, Suilppong was bred among selected lines from F$_1$ seedlings obtained by crossing the female, artificial tetraploid No. 411 which obtained from Chungilppong seedlings, and the male, Kugsang 21. Local adaptability test has been carried out at four places (Suwon, Kongju, Jeonju and Jangsung) for five years since 1997. Leaf quality was tested by silkworm rearing for two silkworm rearing seasons (spring and autumn) at Suwon in 2000. Suilppong was recognized to be superior in productivity to control cultivar, Kaeryangppong. The new cultivar, Suilppong, has following agronomic characteristics as compared with Kaeryangnppong, which is leading cultivar widely cultivating in Korea. It is belonging to Morus alba L. with mixed shapes from the ovate to 5 lobated leaf shape, sprouting in spring nearly the same to the Kaeryangppong (Morus alba L.), high leaf yielding of 20% compared to Kaeryangppong (Morus alba L.). It is adaptable to everywhere except the places where cold damage occurs frequently in Korea. Suilppong is recommended to rear silkworms not only in spring but also in autumn besides for young silkworms.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.323-328
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• 2015

Control efficacy was investigated with fungicides as 3 copper compound, 3 antibiotic fungicides and one fungicide containing to quinolone against the growth of Ralstonia solanacearum on NA medium and the disease occurrence on pepper seedlings. Among 7 fungicides, oxytetracycline was shown the highest activity against a growth of the pathogen in the agar diffusion method, but validamycin showed no activity against the pathogen. With $1000{\mu}g\;mL^{-1}$ of each copper fungicide as copper hydroxide, copper oxychloride+ dithianone and copper sulfate, 2.2, 1.3 and 1.5 mm in size of clear zone only could be found, respectively. In pepper seedling test, oxytetracycline showed a perfect activity in all treatments 7 days after inoculation. However, its activity was decreased from $500{\mu}g\;mL^{-1}$ of treatment over the time. Copper fungicides showed the control efficacy lower than antibiotic fungicides except for validamycin. Based on the results, it was suggested that it would be better to use antibiotic fungicides than copper fungicides to control pepper bacterial wilt in the fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.302-309
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• 1987

One hundred rice varieties were tested for their level of resistance to sheath blight disease at adult plant stage in field condition through 1984 to 1986. Rice plants were grown under ordinary seasonal culture and inoculated by k-2 fungus isolate during three years. k -1 isolate was also inoculated separately in 1984 and test under late seasonal culture was conducted in separate field in 1985. Degree of damage by the disease observed at 25 days after heading was used to identify the level of resistance of the rice varieties tested. Varietal differences of degree of damage were significant in five tests during three years, and the genotypic variance of degree of damage was always higher than environmental variance among varieties tested. Positive correlations between testing years, between cultural seasons, and between isolates inoculated were found in degree of damage of varieties tested for two or three years continuously. Degree of damage by the disease was correlated negatively with heading date of rice varieties except 1984 tests. Thus, the level of resistance should be compared among the variety group having almost same heading date in field condition, and late and extremely late variety groups should be tested for their level of resistance under appropriate environmental condition. Gayabyo, an early heading variety, and SR9713-54-3, a medium heading breeding line, showed consistent lower value of degree of damage during two or three years. These two varieties were selected as moderate resistant germplasm.

• Research in Plant Disease
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• v.17 no.1
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• pp.90-94
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• 2011

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice growing regions of the world. There are no effective ways of protecting rice from the disease. In this study, the bacteriophage (phage) mixtures infecting Xoo were investigated as biological control agent on BLB. The effects of pH, heat and ultraviolet on the stability of phages were investigated to check and increase the possibility of practical use in the field. Phages were rather stable between pH 5 and pH 10. The infectivity dropped sharply when the phages were incubated at $50^{\circ}C$ and more than 90% of the phages were inactivated after two minutes of ultraviolet treatment. The phages were stable for 7 days at the rice plant leaves, and the phages survived 10 times more than other treatments when mixed with skim milk. Although the skim milk increased the stability of the phages, the control efficacy was not effective. However, the phage mixtures reduced the occurrence of BLB when they were treated with Tecloftalam WP or Acibenzolar-S-methyl simultaneously. The results indicated that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• Research in Plant Disease
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• v.14 no.3
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• pp.210-213
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• 2008

The occurrence of Rice stripe virus (RSV) has been confirmed in some parts of South Korea. In the current year, this was observed to be limited in the double cropping zones of the southern region. Earlier, RSV occurred largely in the west coast regions of the country, particularly in Gangwha, Gyeonggi-do in 2001; and Buan, Jeollabuk-do and Seocheon, Chungcheongnam-do in 2007. This study was carried out to determine the nationwide extent of RSV occurrence by investigating RSV infestations in different latitudes and altitudes. Result revealed a recent reported occurrence of RSV in the southern region (Milyang, latitude $35^{\circ}$), a reported occurrence in the northern region (Cheolwon, latitude $38^{\circ}$) in 2005, and in the middle northern region of the east coast (Goseon, latitude $38^{\circ}$) as newly confirmed from this investigation. Results also confirmed the occurrence of RSV in a wide range of altitude from the plains (Milyang, 17 m altitude) to the alpine regions (Jinbu, 576 m) including the middle mountains (Sangju, altitude 285 m). The RSV occurrence in Jinbu in the alpine region and at Goseong and most of the northern end regions were confirmed only this year. The results of the present study confirmed that RSV is a fast-spreading disease in rice plant cultivation regions of the entire country.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.1
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• pp.83-96
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• 2016

Through the research and analysis on the vegetation environment, flora of habitats through documentary and field studies over 14 habitats of Euryale ferox Salisbury within Jeollabukdo, with the objective of acquiring the basic data for forming an environment based on plantation of reservoirs that are composed with Euryale ferox, the following results were obtained. 1. The entire flora of the 14 habitats appeared to be 79 families, 211 genus, 298 species, two subspecies, 30 varieties and six forma, thus, a total of 336 taxa was confirmed. Among these, emergent water plants appeared to compose 17 taxa, floating-leaved plants to compose seven taxa including Euryale ferox floating plants to compose five taxa and submerged water plants to compose two taxa. As a result of analyzing the similarity only over the water plants. The lowest similarity rate appeared between Gamdong Reservoir and Aedang Reservoir, as the similarity rate between the two regions appeared to be 0% as a result of the analysis. Floating-leaved plants, lotuses and caltrops, appeared to be equally inhabiting in Hanseongji at Jeongeup and Seoknam Reservoir at Gochang, which showed the highest similarity rate, in addition to Euryale ferox. 2. When examining the appearance frequency of aquatic plants per growth type, Actinostemma lobatum and Phragmites communis, in addition to Euryale ferox each appeared 11 times, showing a high frequency of 78.6% and Trapa japonica, which is a floating-leaved water plant, appeared ten times(71.4%) and Zizania latifolia appeared eight times(57.1%). In addition, the appearance rate appeared to be high in the order of Persicaria thunbergii, Leersia sayanuka, Ceratophyllum demersum, Echinochloa crusgalli var. oryzicola, Scirpus maritimus, and Nelumbo nucifera. 3. The rare plants discovered in the Euryale ferox habitats pursuant to the IUCN evaluation standards was confirmed to be composed of five taxa, with three taxa including the least concerned species(LC), Melothria japonica at Yanggok Reservoir, Hydrocharis dubia at Myeongdeokji and Ottelia alismoides at Daewi Reservoir, in addition to vulnerable species(VU), Utricularia vulgaris at Sangpyeong Reservoir, along with Euryale ferox. 4. Most of the group or community types of the natural habitats of Euryale ferox appeared to be the Euryale ferix community' and the Daewi Reservoir of Gunsan was defined as caltrop + Euryale ferox + Nymphoides indica community. The green coverage ratio of Euryale ferox per natural habitats showed a considerably huge deviation from 0.03 to 36.50 and as the average green coverage ratio was appropriated as 9.8, it can be considered that maintaining the green coverage ratio of Euryale ferox in a 10% level would be advisable when forming a reservoir with Euryale ferox as the key composition species. 5. The vegetation community nearby the natural habitats of Euryale ferox per research subject area appeared to be composed of three Leersia japonica communities, two communities each for Zizania latifolia community and Trapa japonica community and one community each for Nelumbo nucifera community, Nymphoides peltata + Typha orientalis community, Trapa japonica + Nelumbo nucifera community, Hydrocharis dubia community, Leersia japnica + Paspalum distichum var. indutum community and Euryale ferox + Trapa japonica community, showing a slight difference depending on the location conditions of each reservoir. Thus, this result may be suggested as a guideline to apply when allocating the vegetation ratio and the types of floating-leaved plants upon planting plants in reservoirs with Euryale ferox as the main companion species.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.64-69
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• 1998

New thirty derivatives of 5,6-dihydro-2-trifluoromethyl-1,4-oxathiin carboxanilide as substrate(S) were synthesized and their fungicidal activities in vivo against rice sheath blight(Rhizoctonia solani) and wheat leaf rust(Puccinia recondita) were examined. The structure activity relationships(SAR) between the activities($pI_{50}$) and a physicochemical parameters of substituents(X) at the phenylcarbamoyl group were analyzed using the adaptive regression analysis method. The 3-methoxy, 11, 3-isopropyloxy, 13 and 3-isopropyl substituent, 25 as X on the phenylcarbamoyl group exhibited the most highest fungicidal activity against the two fungi. The fungicidal potency of the (S) against Puccinia recondita was higher than Rhizoctonia solani. In case of Rhizoctonia solani, the molecular hydrophobicity(${\pi}>0$) and resonance effect(R<0) by meta-alkyl substitutents with electron donating were important factors in determining fungicidal activity. And the HOMO energy(HOMO>0), ABSQ, sum of absolute values of the atomic charges on each atom and specific polarizability(Sp.Pol<0) of (S) were significantly influential towards fungicidal activity against Puccinia recondita.. The interaction between (S) and receptor agonist from the based on SAR studies proceeds through charge-control reaction, and conditions to show higher activity has been also discussed.