• Korean journal of applied entomology
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• v.32 no.3
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• pp.330-337
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• 1993

A bacterium, pathogenic to Nilaparvata lugens Stal. causing high mortality in 3~5 days, were selected and identified as Serratuz marcescens biotype A2a which is not a nosocomlally infective strain. In order to determine the characters of Serratia marcesce'1lS associated with insect pathogenicity, Tn5 mutagenesis was carried out by conjugating with E. coli pJB4J1. Transconjugants were plate-assayed for missing chitinase, protease and DNase activity. A protease negative mutant was selected for missing JOseet pathogenicity. SEM and TEM revealed the presence of bacterial cells in the epithelial tissue of inner abdomal tissue of the hypodermic layer of abdomen. Such a colonization was limmited to the subjacent tissue inside the intacL cuticular epidermis. These observation supported our result of pathogenicity tests of transconjugants.

• Korean journal of applied entomology
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• v.33 no.1
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• pp.19-25
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• 1994

Electrophysiological recordings of antennal responses to common plant volatile chemicals in the rice brown planthopper, Niloparuota lugens (Homoptera: Delphasidae}, were examined. Volatile plant chemicals were generally credited with a major role In host plant location for food or egg laying by many insects feeding on plants as adults and/or as larvae. An mitial examination of extracellular responses has been conducted. Acton potentials recorded from the plaque organs were initially positive-going, biphaslc spikes and the background firing rate of the cells recorded ranged from 1 ~22 impulses/sec. A wide range of responses to changes in concentration of the test chemical was observed. The commonest response was a relatively small increase in exitation with increasing concentration beween 1 J.lg and 100).\g on the filter paper in syringe. Adtivity either peaked at 100 $\mug$ and remained virtually saturated at 1000 f19 or tended to decrease at the highest concentration.

• Korean journal of applied entomology
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• v.23 no.3 s.60
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• pp.166-171
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• 1984

The present studies were conducted to investigate the relative toxicity of several insecticides to the rice insect pests and the predatious spider, Pirate subpiraticus. In laboratory test by topical application, BPMC and MIPC for the plant and leafhoppers were toxic to Nilaparvata lugens, but less toxic to Pirata subpiraticus. Other carbamate insecticides such as carbaryl, carbofuran, and MTMC showed highly toxic effect on P. subpiraticus as well as N. lugens. No organophosphates showed selective toxicity to P. subpiraticus. Thiocyclam, effective to Chilo suppressalis and Sesamia inferens, had highly good selective toxicity to P. subpiraticus. In case of insecticides for Nephotettix cincticeps, BPMC only had a little selective toxicity between N. cincticeps and P. subpiraticus. Organophosphate insecticides which had been reported to induce chemical resistance to N. cincticeps showed high $LD_{50}$ value to N. cincticeps. In pot trials, dust formulation was more toxic to P. subpiraticus than emulsifiable concentrate. It was more toxic to P. subpiraticus to increase number. of insecticide application.

• Korean journal of applied entomology
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• v.58 no.3
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• pp.239-249
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• 2019

This study was carried out to compare on the time of occurrence of 6 major rice insect pests [Lissorhoptrus oryzophilus Kusche, Oulema oryzae Kuwayama, Sogatella furcifera (Horvath), Nilaparvata lugens Stal., Cnaphalocrocis medinalis (Guenee), Mythimna separata Walker] in northern part of the Korean peninsula. Using growing degree days of the insects, we evaluated the number of occurrence generations and the time of occurrence. Over-wintering insects such as L. oryzophilus and O. oryzae showed different occurrence periods in northern regions. The occurrence period of the first generation adults was later in northeast regions than in Korean middle regions and more later both in northern alpines and in northern parts of east sea. In addition, the first adults of S. furcifera, N. lugens, C. medinalis, and M. separata occurred between June and early August. However, from late August to September, these insects showed the different occurrence periods in northern regions. Especially, the second adults of N. lugens were not occurred and the second to third generation adults of S. furcifera, C. medinalis, and M. separata showed similar occurrence properties. Based on these properties, the occurrence of major rice insect pests will be less in northeast regions, northern regions of east sea, northern inlands, and northern alpines of the Korean peninsula. However, comparing with their occurrences in northern regions of Gyenonggi and Gangwon provinces, the rice insect pests may show similar occurrence pattern in mid-korean mountains except for pyunggang and yangduk regions as well as in the southern and northern regions of Suyang-san.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.68-74
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• 1998

벼멸구의 카보후란에 대한 저항성 기작을 구명하기 위해 실내에서 카보후란으로 30세대 도태하여 얻은 저항성계통($LD_{50};\;20.3{\mu}g/g$)과 약제를 12년 동안 처리하지 않은 벼멸구 감수성 계통($LD_{50};\;0.3{\mu}g/g$)을 완충용액과 마쇄하여, 105,000g에서 2시간 원심분리하여 얻은 상등액(에스테라제층)과 침전물(P450-산화효소층)을 효소액으로 하여 $^{14}C$-카보후란을 반응시켜 계통 간 대사물 량의 차이를 조사한 바 저해제(piperonyl butoxide; 산화효소저해제, diethylmalate; 글루타치온 전이효소 저해제, iprobenfos; 에스테라제 저해제)와 보조인자 (NADPH; P-450 산화효소, 글루타치온; 글루타치온전이효소)에 상관없이 카보후란의 대사물과 그 양이 계통간 차이가 없었다. 이상의 결과로부터 저항성 벼멸구에서 일반적으로 곤충에서 생화학적 저항성 기구로 잘 알려진 가수 분해 효소의 일종인 에스테라제와 p-450 산화효소, 글루타치온 전이효소의 활성 증가가 저항성 발달에 관여하지 않음을 알 수 있었다.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.75-83
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• 2002

The hypertext-based polychotomous key in m (World Wide Web) was developed to improve the identification accuracy of planthoppers caught by the light trap in Korean paddy fields. The effects of it were tested by 12 students who are not familiar at the identification of insects. When they used the hypertext, it was improved that the ability of them to recognize Sogatella furcifera (Horvath) and Laodelphax striatellus (Fallen). Identification accuracy of the former was increased significantly from 56% to 83% and that of the latter was also increased significantly from 47% to 80%. However, many students still have difficulty in the recognition of Nilaparvata lugens (Stal).

• The Korean Journal of Ecology
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• v.21 no.1
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• pp.15-26
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• 1998

This study was conducted to analyze arthropod community patterns in smallrice fields managed by different cultural methods [Conventional and Low Input Sustainable Agriculture(LISA)] in Suwon in 1995 and 1996. A half of nitrogen fertilizers and a quarter of pesticides were applied in the LISA field compared to in the conventional field. Total 15 orders and 43 families of arthropods were collected in two years. No differences were found in arthropod abundance and arthropod species composition between two differently practiced fields. The arthropod community was analyzed using guild categories. The arthropods were found in the order of 'pest(phytophag)>natural enemy>non-pest' in their densities. The pest species were mainly Homoptera and dominated by Delphacidae (Nilaparvata lugens Stal and Sogatella furcifera Horvath). They constituted > 80% of pest abundance. The spider was the most dominant group in the natural enemy and constituted > 90% of natural enemy abundance. Hunting spiders constituted > 60% of spider abundance and were dominated by Pirata subpiraticus Bos. et Str.(Lycosidae). Pachygnatha clerki Sundevall(Tetragnathidae), Gnathonarium dentatum Weider and Ummeliata angulituberis Oi(Erigonidae) were the dominant species in webbing spiders.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.141-144
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• 1997

Studies were conducted to investigate the incidense of insect pests in transplanted and direct seeded paddy fields in southern region of Korea. Population dencities of the rice green leafhopper (RGLH: Nephotettix cincticeps Uhler) and rice leaffolder (RLF: Cnaphalocroch medinalh Guenee) were higher in machine transplanted than in direct seeded, but the brown planthopper (BPH: Nilaparvata lugens Stal) and smaller brown planthopper (SBPH: Laodelphax striatellus Fallen) were abundant in direct seeded. However, no significant difference was found between machine transplanted and direct seeded fields in the incidense of rice stem borer (RSB: Chilo suppressalis Walker), whiteback planthopper (WBPH: Sogatella furcifera Horvath), and rice stem magot (RSM: C'hlorops oryzae Matsumura). Occurrence of rice key pests were affected more by transplanting time than other cultural practices. Later transplanting induced higher populations of BPH, WBPH, SBPH, RGLH. However, RSB and RLF caused higher damage in earlier transplanted paddy field.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.132-136
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• 1996

These studies were carried out to investigate the occurrence of rice insect pests related to different transplanting times and N-P-K-fertilizer levels of paddy field in Southern region of Korea. The population densities of brown planthopper (BPH: Nilaparvata lugens Stal), whitebacked planthopper (WBPH: Sogatella furcifera Horvath), small brown planthopper (SBPH: Laodelphax striatellus Fallen), green rice leafhopper (GRLH: Nephotettix cincticeps Uhler), rice stem maggot (RSM: Chlorops oryzae Matsumura), striped rice borer (SRB: Chilo suppressalis Walker), and rice leaffolder (RLF: Cnaphalocrocis medinalis Guenee) were affected more by transplanting time than the fertilizer levels. The later transplanting time induced the higher population densities of BPH, WBPH, SBPH, GRLH, RSM, whereas SRB and RLF were affected by earlier transplanting time in paddy field. The major pests except GRLH and SRB were increasingly induced by higher N-fertilizer level in the late transplanting.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.712-723
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• 2016

This paper is to suggest the methods about the environmental risk assessment (ERA) based on non-target insect species for LM rice crop produced by biotechnology. We used some data by the picture dictionary of agricultural pests in Korea, some books for ERA or rice pest ecology, articles about rice ecology, and internet sites and many specialists gave us good advice for this ERA system. We found about 140 insect species using rice crop as their habitat and we discriminated herbivores into Sap feeder, Grain feeder, Defoliator, and Pollen feeder according to their food functional group. We also clarified the potential damage possibility of insect species from LM rice crop. Then, we ranked 10 non-target insect species (Baliothrips biformis, Laodelphax striatellus, Nilaparvata lugens, Mythimna separata, Cnaphalocrocis medinalis, Cletus schmidti Kiritshenko, Scotinophara lurida, Nilaparvata bakeri, Oxya chinensis, Agromyza oryzae) with giving some scores using Geographic distribution, Habitat specialization, Prevalence on crop, Abundance. We showed some environmental risk hypotheses about herbivore, predator, and parasitoid, and infered the impacts of non-target species on LM rice crop. Conclusively, we want to serve this methodology to build the biosafety system from biotechnology crops, and the methodology is to keep public health, sustain the biodiversity, and conserve the natural ecosystems.