• Korean journal of applied entomology
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• v.50 no.4
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• pp.367-372
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• 2011

An unknown planthopper was discovered in 2010 in an apple orchard in Sinpoong-myun, Gongju-si and in a blueberry orchard in Deogsan-myun, Yesan-gun. This pest have arrived 4 or 5 years ago and the population density then rapidly increased. It was identified as Ricania sp. by Dr. Murray J. Fletcher. Adult Ricania sp. was found on 26 plants including blueberry, grape, peach, sumac, japanese angelica, jujube, kiwi, Rubus coreanus, apple, apricot, plum and chestnut. Females lay eggs on 1-year-old branches. The mean number of eggs laid on apple and plum were 18.7 and 15.3, respectively. The mean length of egg masses on apple and plum were 12.35 and 11.45 mm, respectively. The distance between eggs laid on apple and plum branchs were 1.3 and 1.5 mm, respectively. The mean number of eggs in the same length of egg mass on apple and plum branchs were 17.1 and 13.3, respectively.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.236-243
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• 2009

This study was conducted to develop a japonica-type rice cultivar with brown planthopper (BPH) resistance using DNA markers. A doubled haploid (DH) population consisting of 120 pure-lines was established by anther culture of $F_1$ hybrids between 'Samgang', a Tongil type BPH resistance cultivar, and 'Nagdong', a japonica cultivar. To determine the map position of genes responsible for BPH resistance in rice, a genetic map was constructed based on 120 DH lines. A total of 162 molecular markers were classified into 12 linkage groups, covering 1,884 Kosami centimorgan (cM) with an average of 11.6 cM. Five QTLs (qBPR3, qBPR6, qBPR7, qBPR8, and qBPR12) associated with BPH resistance were identified and mapped on chromosomes 3, 6, 7, 8, and 12, respectively, using the genetic map constructed in this study. To analyze the relationship between BPH resistance and agronomic traits, a total of eight QTLs related to the agronomic traits were detected on 12 rice chromosomes. In an analysis of relationships, three QTLs (qBPR3, qBPR7, and qBPR8) showed a linkage with tested agronomic traits. A QTL (qBPR3) located on chromosome 3 (RM282-3023) was closely linked to culm length (qCL3). The QTL (qBPR8) for BPH resistance on the short arm of chromosome 8 also overlapped the region detected in culm length (qCL8).

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.114.2-115
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• 2003

Rice stripe virus causes severe damage to rice in Korea, Japan and China. RSV is a type member of the tenuivirus group and transmitted by the small brown planthopper, Laodeiphax striatellus, in a persistant manner. Until now, occurrence of RSV is limited in of southern part of Korea. But recently occurrence of RSV is increasing and spreading in central part of Korea including Chungcheong and Kyonggi province. So we analyzed recent occurrence trend of RSV which is increased and cloned and sequenced coat protein gene for isolating of RSV strain. Infected rice of each species(Ilpumbyeo, Sindongjinbyeo, Keumobyeo-2, Dongjinbyeo, Jongnambyeo, Samcheonbyeo, etc.)is collected, we extracted total RNA from infected leaves and detected RSV viral RNA by reverse transcription(RT)-PCR using specific primer of coat protein gene. The result of RT-PCR, we observed specific band. We already cloned cDNA from the band, is analyzing sequence variety and homology of each species.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.68-75
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• 1993

Morphometric investigations of the leg characters of both sexes of brachypterous Korean N. lugens biotypes were made. Simple and multivariate statistical analyses revealed that the three N. lugens biotypes differed from one another. The amount of variation and segregation between and among the three biotype populations were approximated by the scatter plot diagrams based on the computed discriminant scores. The variables of leg characters provided the most significant segregations of three biotype populations, thus, categorizing the three biotypes as distinct intraspecific populations of N. lugens.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.137-141
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• 2005

Though many insecticides are commercially available, development of resistance, pest resurgence and effects on non-target organisms led to the search for alternate insect pest management (IPM) strategy based on larval growth and reproductive fitness. Reproductive potential of insects depends on its acquiring of vitellogenic competence which is under hormonal control. Exogenous application of analogues of JR (JHAs) and ecdysterone could derail normal development and reproduction in insects by manipulating an array of physiological processes. In the rice pest, brown planthopper, Nilaparvata lugens, JHA, hydroprene induced metathetely from the fifth (final) instar nymphs in an age-dependent manner. Day 0 of the final instar showed highest sensitivity to induce this abnormal development. Adults emerged from treated day 3 nymphs looked normal. Both the morphotypes were reproductively incompetent and showed partial to complete sterility. Pre-adult exposure of the ovarian tissue to hydroprene suppressed mitotic division of germinal cells and induced abnormalities in the later s1ages of growth and differentiation of ovary in N. lugens. More over the nymphal exposure to hydroprene inhibited patency changes of follicular epithelium and affected competence of the follicles for yolk sequestration. In the absence of ovarian growth and oocyte differentiation, germarium found disintegrated, trophic core regressed and terminal oocytes resorbed. Hydroprene exposure to newly ecdysed brachypterous females did not affect ovarian development and egg production. Proper larval-adult transition appeared as a. prerequisite for vitellogenic competence in N. lugens for which the ovarian tissues must be exposed to ecdysterone in the internal milieu devoid of JH.

• Animal cells and systems
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• v.12 no.1
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• pp.47-52
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• 2008

Effects of wood vinegar on the activity of various insecticides were determined by measuring the mortality of two species of rice planthoppers, Nilaparvata lugens and Laodelphax striatellus. Wood vinegar itself did not show insecticidal activity on planthoppers. When the planthoppers were treated with wood vinegar mixed with one of insecticides such as BPMC, dinotefuran, imidacloprid, carbosulfan or insect growth regulators, the planthopper mortality induced by carbosulfan was greatly increased by the wood vinegar in comparison with a single carbosulfan treatment. Wood vinegar showed no effect on other insecticides. In addition, the wood vinegar-carbosulfan mixture significantly reduced AChE activity of planthoppers, which is a target molecule of carbosulfan. This result suggests that wood vinegar has a synergistic effect on the insecticidal activity of carbosulfan. Our study provides information on a potential role of wood vinegar in facilitation of activity of specific insecticides.

• Korean journal of applied entomology
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• v.16 no.2 s.31
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• pp.87-92
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• 1977

A barley virus disease has been severe in central Korea since 1963. To investigate the causal virus, examination of host ranges, transmission by insect vectors and · electron microscopy were conducted. In electron microscopy, particles identical with northern cereal mosaic virus were observed. The size of baciliform particles ranged from 300nm to 370nm in length and 57-60nm in diameter. The virus was transmitted by the small brown planthopper Laodelphax striatellus (Fallen). The latent period in the vector was seven to nineteen days, with 10 days the most prevalent. Barley, corn, wheat, rye, and oats were susceptible to the virus when inoculated by the insect vectors. It was concluded that the disease agent of the barley disease in Korea is northern cereal mosaic virus. This is the first known report of this disease in Korea.

• Journal of Ecology and Environment
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• v.32 no.1
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• pp.19-25
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• 2009

An arthropod community in a rice ecosystem was surveyed to determine the impact of two insecticides frequently used in Korean rice ecosystems: carbofuran 3GR, which targets the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) in the early season and fenobucarb EC, which targets the brown planthopper, Nilaparvata lugens ($St{\aa}l$) (Hemiptera: Delphacidae) in the mid- and late seasons, respectively. Overall, the application of the insecticides reduced density of total arthropods by 48.4% compared to the untreated field, but their impact on each functional group were different. Carbofuran GR treatment on 1 June reduced the L. oryzophilus population significantly until mid-season. The population of filterfeeding chironomids was also reduced by 50%, whereas the spider population was less disturbed. Fenobucarb EC treatment on 16 August significantly reduced N. lugens and detrivorous entomobryid populations until the late season. Both web-building and wandering spiders were also significantly disturbed by fenobucarb EC although the impact differed according to their behavioral differences. While the population of web-building spiders significantly decreased over time, that of wandering spiders recovered from the disturbance a few weeks later.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.317-322
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• 1993

Morphological investigations of the abdominal lateral lobes in females and the unguitractor p plates in the tarsi of legs in male and female N. lugens among the three Korean N. lugeηs bio-types revealed that the three biotypes varied from one another. The presence of a distinct ‘cut’ on the lateral lobes in brachypterous females distinguished Biotype 2 from Biotypes 1 and 3. The highest frequency of inserted unguitractor plates in fore-and mid-tarsal segments was exhibited by Biotype 2 in both sexes of each morphs.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.13-13
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• 2017

By the progress of genome sequencing, infrastructures for marker-assisted breeding (MAB) of rice came to be established. Fine mapping and gene isolation have been conducted using the breeding materials derived from natural variations and artificial mutants. Such genetic analysis by the genome-wide dense markers provided us the knowledge about the many genes controlling important traits. We identified several genes or quantitative trait loci (QTL) for heading date, blast resistance, eating quality, high-temperature stress tolerance, and so on. NILs of each gene controlling heading date contribute to elongate the rice harvest period. Determination of precise gene location of blast resistance gene pi21, allowed us to overcome linkage drag, co-introduction of undesirable eating quality. We could also breed the first practical rice cultivar in Japan with a brown planthopper resistance gene bph11 in the genetic back-ground of an elite cultivar. Discovery of major and minor QTLs for good eating quality allowed us to fine-tune of eating quality according to the rice planting area or usage of rice grain. Many rice cultivars have bred efficiently by MAB for several traits, or by marker-assisted backcross breeding through chromosome segment substitution lines (CSSLs) using genetically diverse accessions. We are also systematically supporting the crop breeding of other sectors by MAB or by providing resources such as CSSLs. It is possible to pyramid many genes for important traits by using MAB, but is still difficult to improve the yielding ability. We are performing a Genomic Selection (GS) for improvement of rice biomass and grain yield. We are also trying to apply the genome editing technology for high yield rice breeding.