• Korean journal of applied entomology
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• v.41 no.4
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• pp.269-277
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• 2002

Ecological studies on entomopathogenic nematodes are required to increase control efficacy against target insect pests and to obtain basic information for mass production. Thus, effect of temperature and nematode concentration on infectivity and reproduction of Steinernema carpocapsae Pocheon and that of exposure time and soil depth on infectivity were examined using Galleria mellonella larvae. Infectivity and reproduction were examined at five temperatures, 13, 18, 24, 30 and 35$^{\circ}C$ with seven concentrations, 0, 5, 10, 20, 40, 80 and 160 infective juveniles (IJs)/larva. Temperature and nematode concentration influenced infectivity and reproduction of S. carpocapsae Pocheon. Although G. mellonella larvae were killed by S. carpocapsae Pocheon at all given temperatures and nematode concentrations, mortality was higher at 24$^{\circ}C$ than other temperatures. Lethal time of G. mellonella by S. carpocapsae Pocheon was shorter with increasing temperature and nematode concentrations. S. carpocapsae Pocheon was not established in G. mellonella at 13 and $35^{\circ}C$. Time for the first emergence from G. mellonella cadaver was longer $18^{\circ}C$ (about 20 days) than 24 and $30^{\circ}C$ (about 5 days). The highest number of progenies was obtained at $24^{\circ}C$ with 80IJs/1arva, i.e., $18.8$\times$10^4$IJs were produced from a larva. In the exposure time assay, G. mellonella death was recorded in 10 minutes when 300 IJs were inoculated per larva. When S. carpocapsae Pocheon was inoculated at the rate of $10^{9}$ IJs/ha to G. mellonella at the depth of 0, 2, 5 and 10 cm of sand columns, 100% mortality and similar sex ratio were observed but number of established IJs in cadaver was decreased with deepening the soil depth. The results indicated that optimum temperature for infectivity and reproduction of S. carpocapsae Pocheon was $24^{\circ}C$ In addition, S. carpocapsae Pocheon was effective to target insects within 5 cm from the soil surface.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.1
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• pp.21-28
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• 2007

The bioaccumulation of Pb and Cd dissolved in seawater was assessed measuring the concentrations recorded within blue mussel (Mytilus edulis) and oliver flounder (Paralichthys olivaceus) after two weeks exposure period. The Pb and Cd concentration within the whole body of two testing organisms increased according to the exposure concentrations, and the such tendency was clear specially from the mussel. Maximum metal concentration reached $5,260({\pm}70)\;{\mu}g/g$ for Pb reared under 5.0 mg/L Pb, $1,040({\pm}40)\;{\mu}g/g$ for Cd reared under 1.0 mg/L Cd in the mussel, and indicated that the bioaccumulation of Pb and Cd was directly related to the rearing medium concentrations. Bioconcentration factors (BCF) reached very high values for Pb (maximum value: $12,100{\pm}1,400$) in the mussel reared under lowest Pb concentration (0.01 mg/L). The BCF value for Cd in the mussel were also far higher at exposure to low Cd concentration than high Cd concentration. At higher external concentrations, the BCF for Cd and Pb declined. This demonstrated the ability of two testing organisms to rapidly uptake heavy metals particularly when exposed to low external concentration. The mean Pb concentration was slightly higher in the gill of mussel than in the digestive gland, while Cd showed a higher level in the digestive gland than in the gill.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.139-142
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• 1984

Short-term acute toxicity of synthetic detergent(LAS) to larvae of loach, Misgurnus angillicaudatus was examined by static bioassay. The larvae were exposed to 15 different concentration of synthetic detergent for 16, 48, 72, 96 and 120 hours in order to determine median lethal concentration($LC_{50}$). The $100\%$ mortarlity of larvae was showed within 120, 96, 48 and 16 hours for 6, 18, 30 and 38 ppm, respectively. The median lethal concentration values of the larvae were 12.59 ppm for 48 hours, 4.00 ppm for 96 hours and 1.02 ppm for 120 hours. The permissible toxicant concentration of acute toxicity to larvae was $0.37{\sim}0.43$ ppm, and application factor of the synthetec detergent was $0.093{\sim}0.108$. The median lethal time($LT_{50}$) for different concentration also was determined. The $LT_{50}$ of 0.2 ppm was found within 165.1 hours and 2 ppm was 106.2 hours, while the $LT_{50}$ of 8 ppm was 60.3 hours and that of 38 ppm was 23.5 hours.

• Asian Journal of Turfgrass Science
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• v.12 no.2
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• pp.127-140
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• 1998

곤충병원성 선충의 이용 효율을 높이기 위하여 곤충병원성 선충 상호간 또는 선충과 곤충병원성 곰팡이와의 상호관계를 알아보았다. Steinernema glaseri는 기주의 무게에 따라 성충수에서는 차이가 없었으나 침입태 유충수에서는 차이가 있었다. 선충의 접종 농도에 따른 침입 발육된 성충수는 기주당 20마리 이하의 접종에서는 차이를 보였으나 40마리 이상 1,000마리 접종구에서는 차이가 없었고, 증식된 유충수도 기주당 1,000마리 접종구에서 현저히 적은 것을 제외하고는 차이가 없었다. 동일 기주에서의 선충 상호간 관계에서는 steinernematid 선충에 의한 기주 치사율이 heterorhabditid 선충에 의한 것보다 높았다. 즉, 서로 다른 종의 곤충병원성 선충을 동일 기주에 접종하였을 때, S. carpocapsae 포천에 의한 기주 치사율은 $76.2\pm$4.8%였고 Heterorhabditis bacteriophora 함양에 의한 치사율은 $23.8\pm$4.8%였다. 또한 S. carpocapsae 포천에 의한 기주치사율이 각각 $90.5\pm$4.8%와 $80.9\pm$4.8%, H. bacteriophora NC 1에 의한 것은 9.5$\pm$4.8%였다. S. glaseri NC와 H. bacteriophora 함양 및 H. bacteriophora NC 1을 동시 접종하였을 때는 S. glaseri NC에 의한 것이 각각 $61.9\pm$9.65%와 $80.9\pm$4.8%, H. bacteriophora 함양에 의한 것이 $38.1\pm$9.5%, H. bacteriophora NC 1에 의한 것이 $19.1\pm$4.8%였다. 그러나 두 선충의 동시 감염은 관찰되지 않았다. 그리고 S. carpocapsae All과 곤충병원성 곰팡이인 Beauveria brongniartii를 동시 또는 곰팡이를 먼저 처리했을 때는 곰팡이 12시간 전 처리부터 선충과 곰팡이의 동시 감염이 관찰되었고, H. bacteriophora NC 1는 곰팡이 6시간 전 처리부터 동시 감염이 관찰되었다. 선충에 의한 감염과, 곰팡이에 의한 감염, 선충과 곰팡이 동시 감염은 곰팡이 48시간 전 처리부터 관찰되었다. 그러나 유충 증식수는 선충 단독 감염보다 동시 감염충에서 현저히 떨어졌다.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.201-209
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• 2006

Five strains of Korean entomopathogenic nematodes (EPN), steinernematids and heterorhabditids were evaluated and tried in laboratory, pot, and vegetable greenhouses for environmentally friendly control of diamondback moth (DBM), Plutella xyiostella, from 2002 to 2005. LC$_{50}$ values of five EPN strains against DBM were different depending on nematode strain and DBM instar. LC$_{50}$ value of Steinernema carpocapsae GSN1 (GSN1) was the lowest representing 2.6$\sim$3.9 infective juveniles (Ijs, 3rd stage) to 2nd to 4th instars of DBM. Pathogenicity of five effective strains against DBM was different depending on nematode strain, concentration, application times, and vegetable in pot. The most effective nematode was GSN1. Steinernema spp. was more effective than Heterorhabditis spp. against DBM. Two or three times of applications of EPN were effective regardless of nematode strain and concentration in pot. Efficacy of EPN was different depending on vegetable species. Efficacy was higher on Chinese cabbage, red mustard, and Ssamchoo than that on cabbage, kale, and leaf broccoli. Efficacy of GSN1, Steinernema GSNUS-10, Steinernema CSNUS-14, and Heterorhabditis GSNUH-1 was variable depending on nematode strain, concentration, application times, and vegetable in greenhouse experiments. GSN1 was the most effective and 100,000 infective juveniles per m$^2$(=$1\times10^9$ Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale in greenhouse.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.324-330
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• 2020

Ozone (O₃) is a general disinfectant to remove micro-pollutants in water treatment system. Previous studies have reported effect of ozone to bacteria and pathogens removal, but its effect to the relatively large organisms has little known. In this study, we investigated potential effects of ozone toxicity to the non-bite midge larvae (Glyptotendipes tokunagai) with accumulate mortality, coloration change and expression of heat shock protein 70 (HSP70). The accumulate mortality rate of G. tokunagai increased in a dose-time dependent manner and the highest mortality rate was observed to 75% at 30 minute of exposure duration with 2.0 ppm of ozone concentration. Exposure to ozone was a factor increasing body color of the larvae. The tendency of HSP70 mRNA expression showed up-regulation in ozone exposure at 20 minute. After that time, the expression of HSP70 in exposed group decreased to a similar level of control group. Our results clearly showed that ozone toxicity affects physical and molecular activity of G. tokunagai, implying the potential hazardous of ozone in the aquatic ecosystem including macroinvertebrates.

• Korean journal of applied entomology
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• v.49 no.1
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• pp.61-67
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• 2010

Effect of inoculation level on pathogenicity, development, and propagation of entomopathogenic nematode, Steinernema arenarium was investigated using the last instar of great wax moth, Galleria mellonella. Pathogenicity of S. arenarium was higher with increasing inoculation level representing 82% at the rate of 5 infective juveniles (IJs) while >98% at the rate of >10 IJs. The number of IJs penetrated into the host was 2.7, 5.0, 7.4, and 12.2 at the rate of 5, 10, 20, and 40 IJs, respectively while 24.3 at the rate of 80 IJs and 40.2 at the rate of 160 IJs. Inoculation level did not affect female adult size (4,616 to 6,444 ${\mu}m$) while affected male adult size (1,600 to 1,934 ${\mu}m$). The rate of stunted female adults was 70.2% at the inoculation level of 80 IJs and 63.7% at the inoculation level of 160 IJs. The number of progenies was 20,431, 26,696, 47,943, 50,516, 58,701, and 74,235 at the rate of 5, 10, 20, 40, 80, and 160 IJs, respectively. The body lengths of IJs were different depending on inoculation level ranging from 636 to 1,496 ${\mu}m$.

• Korean journal of applied entomology
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• v.30 no.4
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• pp.227-232
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• 1991

The pathogenicity of entomopathogenic nematodes Sfeinernema earpocapsae and Heferorhabditis baeferiophora was evaluated against forest insect pests, alder leaf beetle Agelastiea eoerulea, pellucid zygaenid Pryeria siniea, and box-tree pyralid Glyphodes perspeetalis. Alder leaf beetle larvae were exposed to S. earpocapsae at concentration of 0, 25, 50, and 100 nematodes and to H. baeferiophora at concentration of 0, 10, 20, and 40 nematodes per larva on alder leaves. Mortalities of 1st instar lavae were 85.4 $\pm$ 4.1-100%, 2nd instar larvae 80.0 $\pm$ 5.8-100%, and 3rd instar larvae 65.0 $\pm$ 10.8-100% in S. earpocapsae and those of 1st instar larvae were 82.5 $\pm$ 6.9-100%, 2nd instar larvae 77.5 $\pm$ 4.7-100%, and 3rd instar larvae 55.0 $\pm$ 13.5-100% in H. baeferiophora treatment. When pellucid zygaenid larvae were exposed to S. earpocapsae at concentration of 0, 5, 10, 20, 40, and 80 nematodes and to H. baeteriophora at concentration of 0, 2, 5, 10,20, and 40 nematodes per larva, mortalities were 98.9 $\pm$ 1.1-100% in S. earpocapsae and 26.7 $\pm$ 5.1-74.5 $\pm$ 6.2% in H. baeferiophora. The mortalities of box-tree pyralid larvae were 97.8 $\pm$ 1.5-100% in S. earpocapsae treated with concentration of 0,20,40, and 80 nematodes per larva and those were 92.0 $\pm$ 6.2-98.9 $\pm$ 1.1 % in H. baeferiophora treated with con'||'&'||'not;centration of 0, 10, 20, and 40 nematodes per larva.

• Journal of Sericultural and Entomological Science
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• v.22 no.2
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• pp.8-12
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• 1981

Practical application of silkworm artificial diet is very desirable to save labour in sericultural industry as the problem of labour shortage is becoming serious in Korea. However, silkworms reared on the artificial diet are more susceptible to viruses than those reared on mulberry leaves because of the lower anti-viral activity of gut juice of silkworms grown on artificial diet compared with that of silkworms grown on mulberry leaves. In this study, authors investigated the varietal difference of silkworm larvae, Bombyx mori L., reared on artificial diet which contained 20 percent of dried mulberry powder, in the susceptibility to nuclear polyhedrosis virus (NPV). The results showed that there is no difference in susceptibility to NPV among tested varieties when high concentration of NPV was admitted to silkworm larvae, but varietal difference appeared in lower concentration admitted. Among 7 hybrids tested, Hansaeng 1${\times}$Hansaeng 2 was most resistant to NPV with an $LC_{50}$ of 2.7${\times}$10$\^$6/ and Jam 111${\times}$Jam 112 was also more resistant comparatively than other hybrids.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.311-314
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• 2004

Toxicity test fur various synthetic lubricant oil bases derived from biodiesel was carried out. The earthworms(Eisenia fetida) were maintanied in artificial soil consisting of sand for 14 days. Eisenia fetida was cultivated at temperature of $20{\pm}2^{\circ}C$, pH 6.0 $\pm$ 0.5 and moisture of $31\~37\%$. Pentaerythritol(PE) lubricant oil base was tested for acute toxicities to Eisenia fetida. The earthworms were exposed to each lubricant oil with various concentrations of lubricant oil base. After 14 days, the number of surviving earthworms and thier weight alteration during the test period was determined. $LC_{50}$(lethal concentration when $50\%$ of the population were killed) pentaerythritol was determined to be 1,555 mg/kg soil dry weight.