• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.30-35
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• 2001

Diamondback moth (Plutella xylostella L.) recently became a single worst insect which is not controlled effectively by organophosphorus and carbamate insecticides in Kangwon alpine croplands. The objective of this study was to determine if diamondback moth has developed a resistance to organophosphorus and carbamate insecticides. Resistance of diamondback moth, collected at Keichon, Jangpyong Taebaek, Chunchon, and Hongchon, was determined by the concentration required to kill fifty percent of population, $LC_{50}$. Their response of resistance varied to insecticides and locations: Taebaek populations were 35 and 70 times more resistant to chlorpyrifos and fenitrothion, respectively, than susceptible(S) population. Hongchon populations were 94 and 254 times more resistant to chlorpyrifos and fenitrothion, respectively, than S population. In addition, Chunchon populations were 37 and 19 times more resistant to profenofos and benfuracarb, respectively, than S population. However, the field populations did not differ in resistance to diazinon, phenthoate, flupyrazofos, carbofuran, and furathiocarb. This study show that field populations of diamondback moth found in Kangwon alpine vegetable croplands have developed a resistance and/or multiple resistance to some insecticides, implying that farmers are losing organophosphorus and carbamate insecticide options for selective control in vegetable crops.

• BMB Reports
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• v.43 no.8
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• pp.573-578
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• 2010

Several organophosphorus (OP) insecticides can selectively kill the silkworm maggot, Exorista sorbillans (Es) (Diptera: Tachinidae), while not obviously affecting the host (Bombyx mori) larvae, but the mechanism is not yet clear. In this study, the cDNA encoding an acetylcholinesterase (AChE) from the field Es was isolated. One point mutation (Gly353Ala) was identified. The Es-353G AChE and Es-353A AChE were expressed in baculovirus-insect cell system, respectively. The inhibition results showed that for eserine and Chlorpyrifos, Es-353A AChE was significantly less sensitive than Es-353G AChE. Meanwhile, comparison of the I50 values of eserine, dichlorvos, Chlorpyrifos and omethoate of recombinant Es AChEs with its host (Bombyx mori) AChEs indicated that, both Es AChEs are more sensitive than B. mori AChEs. The results give an insight of the mechanism that some OP insecticides can selectively kills Es while without distinct effect on its host, B. mori.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.365-373
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• 2005

This study was carried out for looking into the status of susceptibility of pest insects to insecticides. Each insect Brown planthopper(BPH), Green leaf hopper(GLH), Smaller brown plant hopper(SBPH), Rice water weevil(RWW), were captured at various areas where the host crops were being cultivated and the susceptibility level of each pest insect was investigated. The susceptibility of each pest insect varied by insect species and areas where they were caught. BPHs kept higher level of susceptibility comparing to susceptible reference strain except to most of tested insecticides except imidacloprid (Resistance ratio was 68). The susceptibilities of GLH and SBPH to most of insecticides for their control did not developed markedly since 1976 except fipronil and imidacloprid which is widely used for WRR control. The insecticides used for control of WRR were very effective even at the concentration of one fourth of recommending concentration, but in 2000 suwon strain of WRR showed markedly reduction of susceptibility to carbofuran.

• Korean journal of applied entomology
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• v.10 no.1
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• pp.13-22
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• 1971

This experiment was conducted to investigate the differences of the in vitro inhibitory effect of various organephobphorua insecticides on the chlinesterase from rice stem borer and those of the toxicity of them against the insect, with special references to the relationship between the cholinesterase inhibition and the toxicity. The results obtained were summarized as follows: Phosphate compounds shelved stronger inhibitory effect on the cholinesterase than thhiophosphate compounds, but was not stronger in toxicity than the latter. Diethoxy compounds were not always stronger than dimethoxy in cholinesterase inhibition and the toxicity of organophosphorus insecticides. The organophosphorus insecticides that inhibited strongly the cholinesterase were not always stronger in the toxicity.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.97-108
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• 2005

Samples of water, soil, and sediment were taken from 10 streams near Andong, Korea in May 2004. To assess the degree of environmental pollution of each stream, chemical pollutants such as total notrogen (T-N), total phosphorus (T-P), chemical oxygen demand (COD), heavy metals, organophosphorus pesticides, organochlorine pesticides, and dioxin-like PCB congeners were analyzed by standard process tests or U.S. EPA methods. In addition, biomarkers originated from insect immune systems of beet armyworm, Spodoptera exigua, were used to analysis of the environmental samples. Except Waya-chun stream showing T-N content of 9.12 mg/L, most streams were contaminated with relatively low levels of overall pollutants in terms of T-N, T-P, and COD, compared to their acceptable environmental levels designated by the Ministry of Environment. Contents of Pb and Cd in samples of each stream were much lower than environmentally permissible levels. However, several times higherconcentrations of Pb and Cd were found in locations at Mi-chun, Kilan-chun, and Hyunha-chun streams, in comparison with other streams. Diazinon, parathion, and phenthoate compounds among organophosphorus pesticides were detected as concentrations of 0.19, 0.40, and $1.13\;{\mu}g/g$, respectively, from soil sample collected in the vicinity of Mi-chun stream. On the other hand, 16 organochlorine pesticides and 12 dioxin-like PCB congeners, known as endocrine disrupting chemicals, selected in this study were not found above the limit of detection. Biomarker analyses using insect immune responses indicated that Waya-chun stream was suspected as exposure to environmental pollutants. Limitation and compensation of both environmental analysis techniques are discussed.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.353-360
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• 2003

For the simple rapid bioassay of organophosphorus and carbamate pesticide residues, a mass-production system of acetycholinesterase (AChE, EC 3.1.1.7, MAChE) using baculovirus and insect cell culture was constructed. The cDNA for AChE was synthesized from Drosophila melanogaster in Halla Mountain, the lipid anchor tail was removed by PCR and was used for the site-directed mutagenesis of three amino acid residues (E107Y, F368L, L408F). The mutated cDNA was inserted into the baculovirus vector and expressed in insect cells. Maximum cell growth and enzyme activity were reached when the cells $(2{\times}10^6\;cell/ml)$ were infected four times at four-day-intervals. His-tag containing MAChE was purified using Ni-NTA column and used for characterization. The activity was maintained under various pHs (3-10) and temperatures $(20-50^{\circ}C)$ under experimental conditions. As an extraction solution for pesticides, methanol is more effective than ethanol. Against major organophosphate and carbamate pesticides, the MAChE showed better sensitivity than AChE and AChE from housefly (Taiwan).

• Korean journal of applied entomology
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• v.40 no.4
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• pp.327-335
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• 2001

In order to establish a whitefly control system using conventional groups of insecticide(carbamate, organophosphorus and pyrethroid insecticides), three alternative application methods were designed on the medium growth stage of cucumber. To discriminate the effectiveness of these sequences observed were the residual activity of insecticides, frequency of insecticide applications, residue of insecticides in cucumber leaves, development of insecticide resistance in whitefly, and yield of fruits. Spraying furathiocarb, a carbamate insecticide, was very effective in reducing the frequency of application for the control of white flies. The effectiveness of furathiocarb was enhanced by the potentiation process to carbofuran, the long residual activity, and the lower development rate of insecticide resistance. Methion, an organophosphorus insecticide, did not show resistance development after successive use but resulted in short residual activity. However, other organophosphates, profenofos and phenthoate, lost their activity by the resistance development. Decreasing activity was common to pyrethroids, deltamethrin and zetacypermethrin due to resistance. From these results it could be drawn a conclusion that furathiocarb, a carbamate insecticide, was the most desirable among conventional insecticide groups for the management of greenhouse whitefly population on the cucumber. To prevent an outbreak of the insect pest by various cause, it was recommended to choose acetamiprid, a nicotinoid, which showed very good control efficacy to the resistance insects to conventional insecticides.