• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.41-47
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• 2014

This study was performed to evaluate the exposure level of organophosphorus and pyrethroid pesticide to floriculture workers and florists. The urinary dialkylphosphates, metabolites of organophosphorus insecticides, including dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP), diethylthiophosphate(DETP) and pyrethroids of metabolites, cis/trans DCCA, DBCA, and 3-PBA were analysed to evaluate the exposure of organophosphorus and pyrethroid pesticide to floriculture workers and florists. The concentration of DMP is highest in floriculture workers. but the concentration of DETP is highest in retail florist. The concentration of 3-PBA is highest in floriculture workers. The amount of organophosphorus and pyrethroid pesticide expusure is highest in flower workers, wholesale florist and retail florists are followed. The management for reducing pesticide exposure to floriculture workers and wholesale florist is required.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.286-292
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• 2016

Malaria is mainly transmitted by Anopheles sinensis which is dominant species in malaria high-risk area, northern part of Gyeonggi province in Korea. Pyrethroid insecticide is used for malaria vector, An. sinensis in Korea and the previous investigation consistently reported insecticide resistance from the vector. This study investigated insecticide susceptible and resistant alleles from An. sinensis and the status of malaria vector control in malaria high-risk area. For the study, An. sinensis collected from Paju, Gimpo and Ganghwa were sequenced for kdr detection. In Paju, there was no homozygous susceptibility and all of tested samples had homozygous or heterozygous resistance. There were 6.7% for susceptible homozygosity and 93.3% for resistant homozygosity or heterozygosity in Gimpo. Furthermore, the percentages of homozygous susceptibility and homozygous or heterozygous resistance in Ganghwa were 5.7% and 94.3% respectively. The results showed that the frequency of the insecticide resistance from An. sinensis in malaria high-risk area were increased much more than the previous investigation. Hence, this study suggests that malaria vector control programs should have to be prepared for the management of pyrethroid insecticide resistance.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.41-46
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• 2015

This study was conducted to evaluate the use of biological monitoring to determine the factors that influence the effects of exposure to pyrethroid pesticides among highland cabbage farmers. Urine was collected from farmers who was cultivating Chinese cabbage in the relatively highground in Gangwon-do the morning following pesticide application and was analyzed for cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcy-clopropane carboxylic acid (DCCA) and 3-(2,2-dibromovinyl)-2,2-dimethyl cyclopropane carboxylic acid (DBCA). Factors affecting exposure to pesticides, such as wind speed, spraying location, and the use of protective gear, were also investigated. Statistical analysis was performed by the Kruskal-Wallis test. Our analysis indicated that highland cabbage farmers were exposed to a higher level of pesticides than the general public or other types of farmers. When the wind speed was low, workers who sprayed pesticides were exposed to a higher level of pesticides compared to the exposure level in an assistant. However, there was no difference in exposure between the two when wind speed was high.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.300-304
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• 2016

The aim of this study were to evaluate the exposure level of pyrethroid pesticide according to spraying machine type. The urinary metabolites of pyrethroid pesticide in apple farmers were analyzed to determine the exposure level of pyrethroid pesticide. The result shows that, the spraying volume was greater in SS sprayer group than in power sprayer group. But multi variate analysis which adjust spraying volume and field area, there were no difference of urinary metabolites between two sprayer machine. To make more accurate model of pesticide exposure, the factors influencing pesticide exposure should be determined and further study should be done.

• Korean journal of applied entomology
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• v.52 no.1
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• pp.35-43
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• 2013

All tested Korean populations of the diamondback moth, Plutella xylostella, are known to be resistant especially against pyrethroid insecticides by mutation in its molecular target, para-sodium channel. Moreover, P. xylostella is able to develop resistance against most commercial insecticides. This study was performed to develop an efficient control technique against P. xylostella by a combined treatment of an endoparasitoid wasp, Cotesia plutellae, and a microbial insecticide, Bacillus thuringiensis. To investigate any parasitism preference of C. plutellae against susceptible and resistant P. xylostella, five different populations of P. xylostella were compared in insecticide susceptibilities and parasitism by C. plutellae. These five P. xylostella populations showed a significant variation against three commercial insecticides including pyrethroid, organophosphate, neonicotinoid, and insect growth regulator. However, there were no significant differences among five P. xylostella populations in their parasitic rates by C. plutellae. Moreover, parasitized larvae of P. xylostella showed significantly higher susceptibility to B. thuringiensis. As an immunosuppressive agent, viral ankyrin genes (vankyrins) encoded in C. plutellae were transiently expressed in nonparasitized larvae. Expression of vankyrins significantly enhanced the efficacy of B. thuringiensis against the third instar larvae of P. xylostella. Thus an immunosuppression induced by C. plutellae enhanced the insecticidal efficacy of B. thuringiensis. These results suggest that a combined treatment of C. plutellae and B. thuringiensis may effectively control the insecticide-resistant populations of P. xylostella.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.338-344
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• 1992

This test has been carried out to clear the effectiveness of pyrethroid insecticides to the Diamond back moth, that was complained by a farmer. The results obtained are summarized as follows. Effectiveness of Pyrethroids to suceptable strain and the results of chemical anaysis on the ingredients of pyrethroikds were normal at recommended concentrations. The effect ualue of pyrethroid by which the blocks were only one time treated was 57-59%, whereas the blocks sprayed 4 consecutive times of pyrethroid didn't show any effectiveness as shown in larval increasing rate of 489-552%. Among the results of field test conducted from 1990 to 1991 at 7 area, Dae Gu area showed the highest Effectiveness as 95-98%. However, Pyong Taek area, showed the least effectiveness as 0% in effect value. The resistant population which was collected at Tae kwan Ryung area was resurrected susceptability as much as JMC, in case of Placing it in non-treatment environment, whereas the pupulation which was revealed to pyrethroids for 6 genetations showed as much as 341-544 times of resistance compared with JMC. The non-effectiveness of pyrethroids to Diamondback moth which was complainted by a certain farmer named Mr Ju, was clearly resulted by the development of insect resistance. In Korea, the resistance of Diamondback moth to pyrethroids has developed in some area, as well as the resistance of pyrethroids has developed according to the continuous use of Insecticides, and the susceptability resurrected by stopping the use of pyrethroids. The result from this test would suggest that the pyrethroid insecticides should be applied in turb with other insecticides.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.117-128
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• 2022

In this study, we have examined pyrethroid actions on sodium channels in the pest insect Heliothis virescens. The synthetic pyrethroid permethrin increased steady-state sodium current in H. virescens central neurons and prolonged tail currents (I_Na-tail) due to extreme slowing of sodium channel deactivation. Prolongation of I_Na-tail was evident at permethrin concentrations as low as 60 nM, which modified ~1.7% of sodium channels and 10 μM permethrin modified about 30% of channels. The average time constant (τ₁) of tail current decay was ~335 ms for permethrin-modified channels. These modified channels activated at more negative potentials and showed slower activation kinetics, and failed to inactivate. Permethrin modification of sodium channels was dramatically potentiated by the α scorpion toxin LqhαIT, showing positive cooperativity between two binding sites. The amplitude of the tail current induced by 0.3 μM permethrin was enhanced ~8-fold by LqhαIT (200 pM). Positive cooperativity was also observed between permethrin and the insect-specific scorpion toxin AaIT as 10 nM permethrin potentiated the shift of voltage dependence caused by AaIT (~2-fold).

• Korean journal of applied entomology
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• v.32 no.1
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• pp.24-29
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• 1993

Experiments were conducted to study effects of different bioassay methods on toxicity to the German cockroach (Blattella germanica L.) ith six insecticides. For male adults, by dry film method, the {TEX}$LC_{50}${/TEX} value of chlorpyrifos. fenvalerate, propoxur, permethin, DDVP, and hydramethylnon was 1.79, 1.87, 3.04, 4.37, 32.72, and 270.81 ppm, respectively and the same tendency was shown in the female. For male adults, by topical micro-application method, the {TEX}$LD_{50}${/TEX} value of DDVP and fenvalerate, chlorpyrifls, permethrin, propoxur, hydramethylnon was 2.63, 3.79, 4.51, 6.73, 44.99 $\mu\textrm{g}$/g, respectively and the same tendency was shown in the female. From the diet toxicity method against male adults, the CT value (Concentration%$\times${TEX}$LT_{50}${/TEX}) showed that chlorpyrifos was rapid effective and hydramethylnon was residual effective.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.301-310
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• 2009

For the comparing of mortality of the resistance and susceptible population of Myzus persicae, etofenprox was treated in the recommended concentration of 200ppm. Mortalities of resistance population were 16.7 and 36.7%, and susceptible population were 86.7 and 86.7% after 24 and 48 hours treatment, respectively. For the detect of cross resistance to other pyrethroids, 6 pyrethroids were examined. Mortalities of susceptible and resistance populations were 90 and 31% to deltamethrin, 92 and 23% to lambda cyhalothrin, 81 and 14% to cypermethrin, 70 and 20% to $\alpha$-cypermethrin, 29 and 28% to fenpropathrin, 84 and 29% to fenvalerate, respectively. It was showed that resistance populations were generally resistive to other pyrethroids. On the other hands, for recognized ecological characteristic of M. persicae susceptible and resistance populations life table was tested on the pepper leaves in the petri dish and on the plant in the pot. This results were showed that intrinsic rate of increase ($r_m$), net reproduction number ($R_0$) and generation time in day ($T_c$) were significantly different between two population in both tested. However, life span and reproduction period were slightly different between them. Otherwise, feeding behaviors were tested using EPG technique with non- and treated etofenprox. First potential drop time of susceptible and resistance population was 73.5 and 257.9 sec with non-treated and 93.3 and 1076.2 sec after treated, respectively. Electrical probing signals were 8.2 and 48.8 times with susceptible and resistance individuals after treated etofenprox, respectively. It was supposed that the resistance is more probings than susceptible population. After treated, total feeding time have more 6,728.9 sec on resistance than 965.5 sec on susceptible population. So, total non penetration time of susceptible population was 3,000 sec longer than resistance population.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.329-334
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• 2011

Insecticidal activity of 31 registered insecticides was tested against Metcalfa pruinosa adults. All experiments were conducted at the recommended concentration (ppm) of each insecticide. Among them, 16 insecticides from organophosphates (dichlorvos, fenitrothion, fenthion, methidathion, phenthoate), carbamates (methomyl), pyrethroids (${\alpha}$-cypemethrin, deltamethrin, fenpropathrin, ${\gamma}$-cyhalothrin), neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiamethoxam), and other (endosulfan) showed 100% mortality by spraying on the body of M. pruinosa adults. Dichlorvos, fenitrothion, fenthion, methidathion, phenthoate and endosulfan showed 100% mortality by plant-dipping method. The residual effect was showed 100% mortality in four insecticides (fenitrothion, fenthion, methidathion, phenthoate) at one day after treatment, and three insecticides (fenitrothion, methidathion, phenthoate) were showed the mortality of 90% at three days after treatment.