• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.117-124
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• 2007

Esterase activity was observed after pesticides treatment in eggs of H. axyridis to select low toxicity pesticide. Egg esterases of H. axyridis were examined using an esterase substrate(${\alpha}$-naphthyl acetate). Three esterase isozymes were detected and the activities were inhibited by organophosphorus insecticide (Chlorpyrifos and Phenthoate), organochlorine insecticide(Methidation), triazole fungicide(Hexaconazole and Triflumizole), and pyrimidine fungicide(Nuarlmol). Fecundity and hatchability in adults and eggs of H. axyridis were examined on selected pesticides. Fecundity and hatchability were significantly reduced from H. axyridis adults and eggs treated with the pesticides and the fungicides showed strong inhibition of esterase isozymes activities. However, we also observed the pesticides and the fungicides showed low or non-inhibition of esterase isozymes activities affected on fecundity and hatchability in adults and eggs.

• Korean journal of applied entomology
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• v.59 no.2
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• pp.83-91
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• 2020

We assessed efficacy of spraying pesticides from an unmanned helicopter to control two insect species, Monochamus alternatus and M. saltuarius, which are vectors of pine wood nematodes. Control efficacy of thiacloprid FL (33×), acetamiprid ME (33×), and flupyradifurone SL (33×) was determined by placing caged insects in the canopy of pine trees (Pinus sp). Water-sensitive paper was used to record the spray pattern of pesticide droplets and the degree of coverage; furthermore, we investigated peripheral scattering due to spraying. The three pesticides showed > 96% control efficacy against the targeted vectors, and pesticide droplet spray patterns were similar. Peripheral scattering was observed up to 20 m in front and 10 m to the left, right, and behind the targeted area. The coverage index of all the directions at 5 and 10 m distance was 6-7 and 2, respectively.

• Journal of agricultural medicine and community health
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• v.19 no.1
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• pp.15-23
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• 1994

In order to find out the frequencies of symptoms and the relations between the symptoms and working hours, the numbers of spraying pesticides authors investigated 145 farmers(96 male, 49 female persons) from 6 Myon's of 3 Gun's in Kyeongnam Province. The results were as follows; 1. The most frequent farming years were 1-5 years, fruits were the most common, and working hours were over 9 hours in 41.4%. The commonly used pesticides were insecticides, herbicides, herbicides in order. Only 52.4% of the farmers used masks, and 69.0% bathed after spraying pesticides. 2. The most common symptoms being complained were sweating, lumbago, shoulder pain, dizziness, headache, fatigue, decreased vision, weight loss, dyspnea and nausea in order. 3. Dizziness was more common in younger ages and decreased vision was more common in elder ages. Dyspnea and shoulder pain were more common in female farmers. 4. The more longer the working hours, the more complained indigestion, lumbago, shoulder pain and nausea. The more faster came into vinyl-house after spraying pesticides, the more common fatigue and dizziness. 5. The farmers who sprayed more pesticides complained headache, dyspnea, weight loss. 6. Vinyl house workers who worked more than 7 hours complained headache, nausea, decreased vision, lumbago more frequently than who worked less than 6 hours. 7. The farmers who entered in 1-2 hours after spraying pesticides complained fatigue more frequently than those entered after 3 hours. 8. Vinyl house workers without using masks complained dizziness and dyspnea more commonly than those using masks. But headache was more common among those using masks contrary to expectation.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.49-54
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• 2004

The oriental tobacco budworm, Helicoverpa assulta (Guenee) is a major pest of red pepper in Korea. Insecticide spray is a prevalent control tactic in most farms, but an effective control is difficult because the larvae are protected inside the fruit. Objective of this study was to investigate the seasonal occurrence of the male moths using pheromone trap and to evaluate the control efficacy of insecticide applications based on the trap catch data at red pepper fields in Suwon. The results of pheromone trap catch during three years showed that the moth flight activity occurred from late May to early October. Peak periods of the adult flight, which are indicators of each generation, occurred in late June, late July-early August, and late August-early September. Trap catches during the overwintering and first adult generation were closely linked with subsequent damage. Although the trap catch during the second generation was higher than the previous generations, damage level caused by this generation larvae was low. Experiment results revealed that fruit damage by H. assulta could be effectively reduced by five sprays of insecticides based on the trap catch data throughout the season.

• Journal of Environmental Science International
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• v.4 no.4
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• pp.379-386
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• 1995

Permethrin [3-phenox yben zyl(1RS)-cis,tans-3-(2,2-dichloroviny1)-2,2- dimethylcyclopropane carboxylate] insecticides were selected to study adsorption and leaching potentials related to pollution on Commerce silty clay loam soil near Baton Rouge, Louisiana, USA. GLC-ECD chromatogram of permethrin included 32.5 % of cis-pemehin and 67.4 % of trans-permethrin. Extraction efficiencies of is and trmu-pemetun were 92.5 % and 92.3 % in fortified water, respectively and 85.9 % and 88.8 % in fortified soil, respectively. At a 1:10 moi]/water ratio,the Koc values for sis and fan isomers of permethrin were 938 and 877, respectively. Leaching of permethrin was evaluated in soil columns$(5.4 cm i.d. \times 26 cm length)$. Total recoveries of the permethrin applied to the soil column were $84.5\pm3.1%$. When the soil columns were leached with three pore volumes of water, the distributions of cis-permethrin leached were 6.10 % and 0.07 % of amount applied in the untreated zone soil and leachate water, respectively Trans-pemethrin distributions were 5.20 % in the untreated zone soil and 0.05 % in leachate water. Cis and trans-pemethrin was strongly adsorbed to soil. The results of the study showed the strong relationship between adsorption and leaching. Cis and trans-permethrin to be leached into the groundwater in soils with shallow aquifers were suggested a low leaching potential.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.179-188
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• 2006

The toxicities of 37 commercial pesticides for citrus pests were evaluated to H, fallacis. Eight fungicides (difenoconazole, imibenconazole, azoxystrobin, dithianon, fluazinam, procymidon, streptomycin, tribasic copper sulfate), three insecticides (dichlovos, imidacloprid, thiamethoxam) and four acaricides (milbemectin, tetradifon, dicofol, spirodiclofen) had lower effect to the hatchability of eggs N. fallacis. Six fungicides (propineb, difenoconazole, imibenconazole, azoxystrobin, dithianon, procymidon) and three acaricides (bifenazate, tetradifon, spirodiclofen) showed lower contact toxicity to adult N. fallacis. The secondary toxicity of 26 pesticides to N. fallacis adult were evaluated. Two fungicides (fluazinam, streptomycin) and 3 acaricides (machine oil, cyhexatin, halfenprox) showed low toxicity when the prey (eggs of spider mite) was treated with pesticides.

• Korean journal of applied entomology
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• v.31 no.2
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• pp.182-189
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• 1992

The influnces of 9 kinds of solvents on the toxicities against several insect species, phytotoxicity and solubility of compounds were evaluated by means of leaf dipping and spray methods. In case of the spray application, density and vapor pressure seemed to be a contributing factor to lethal toxicity against brown planthopper and diamond-back moth, respectively; the bigger the property of density and the smaller the vapor pressure gave the stronger toxicity. It appeared that the toxicity of solvents was not correlated with anyone of physical properties such as boiling point, dipole moment, dielectric constant, surface tension and viscosity. Spray treatment gave more toxicity to insects than leaf dipping treatment. Although dielectric constant and dipole moment seemed to be contributing factors to phytotoxic damage to rice seedling and bean plants, respectively, no general correlation between phytoxicity and the other physical properties was found. Leaf dipping application caused stronger phytotoxicity than spray application. It is concluded that 5% acetone solution may be most suitable to test chemicals because of its favorable solubility of compounds, lower toxicity to insects, and lower phytotoxicity.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.79-83
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• 1985

Plant damages and yields of the different rice cultivars to brown planthopper (BPR), Nilaparvata lugens S., were observed for the evaluation of varietal resistance in paddy fields. Twenty nine Korean cultivas were transplanted in paddy fields with three plots of no insecticide, no insecticide and fungicide, and no fungicide at Haenam, southern coastal area in 1983. Among 6 varieties with BPR resistant genes, Samgang, Gaya, Hangangchal, and Cheongcheong showed very low populations of BPR and no damages on all treatments. Milyang 30 and Wonpung among them had considerable populations of BPR. Seokwang and 23 others showed high populations and serious damages. Yield increasea(%) with insecticides were low on Gaya(12%), Samgang(29%) and Hangangchal(35%), but very high on Bongkwang(260%), Palgueum(223%), Songjeon(200%), and Guanauk(200%).

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.604-611
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• 1993

Supercritical Fluid Chromatography(SFC) has become a technique for solving problems that are difficult by other chromatographic methods. However, the most widely used fluid, is no more polar than hexane. Polar samples which are difficult to be analyzed with pure supercritical C$O_2$ because of their high polarity can be separated by adding polar modifiers to supercritical C$O_2$. In this paper, a new method for monitering the mobile phase composition in modified supercritical fluid chromatography was developed. The amount of water dissolved in supercritical C$O_2$ was measured by amperometric microsensor which is made of thin film of perfluorosulfonate ionomer (PFSI). The amount of water dissolved in supercritical C$O_2$ stayed constant for a much longer time than with a saturator column. With this new mixing device, we could do good separations for insecticides and fungicides which are difficult to separate with pure C$O_2$.

• Environmental Mutagens and Carcinogens
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• v.25 no.1
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• pp.6-12
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• 2005

Many compounds might become activated after absorption of UV light energy. In some cases, the resulting molecule may undergo further biological reaction of toxicological relevance related especially to the photo-carcinogenicity resulting from photo-genotoxicity. However, no regulatory requirements have been issued with the exception of guideline issued by the Scientific Committee of Cosmetology, Commission of the European Communities (SCC/EEC) on the testing of sunscreens for their photo-genotoxicity. Thus, the objectives of this study are to investigate the utility of photo-Ames assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-Ames assay was performed on five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an a-adr-energic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and retinoic acid (a retinoid compound closely related to vitamin A). Out of 5 test substances, 3 showed a positive outcome in photo-Ames assay. With this limited data set, an investigation into the predictive value of this photo-Ames test for determining the photo-carcinogenicity showed that photo-Ames assay has relatively low sensitivity (the ability of a test to predict carcinogenicity). Thus, to determine the use of in vitro genotoxicity tests for prediction of carcinogenicity,' several standard photo-genotoxicity assays should be compared for their suitability in detecting photo-genotoxic compounds.