• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.53-58
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• 1975

The local variabilities of resistance to Malathion and NAC (Sevin) were studied during 1973 with the strains of small brown planthopper (Laodelphax striatellus Fallen) collected from Jinjoo, Sunsan, Milyang, Kwangjoo and Iri districts of southern part of Korea. The susceptible lab strain used for this study has been reared successively in the laboratory without exposure to any insecticide since 1970. The insecticides were applied topically in acetone to the thoracic sternum of the adult insects. $LD_{50}$ values of Malathion to the insect were varied with the locality of the planthoppers. Relatively high levels of resistance to Malathion were observed in the strains of Jinjoo and Suntan; showing 27.7 times in female and 24.9 times in male for Jinjoo stram and 18.4 times in female and 13.8 times in male for Sunsan strain as compared with the susceptible lab strain, and in other strains of Milyang, Kwangjoo and Iri the levels of resistance to Malathion were still less than 5 times. However, there was no any specific difference among the strains in susceptibility to NAC. The malathion-resistant strain of the small brown planthopper seemed to be still localized in some regions of· Korea. The susceptibility of the planthoppers to Malathion was varied with the sex; $LD_{50}$ values based on the individual (ug/insect) were higher in female than in male, while the values based on the body weight (ug/g) conversely higher in male than in female.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.828-830
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• 2007

To determine the effects of newly developed insecticide (Ultra) on Sycamore lace bug (Corythucha ciliata), ten leaf discs were sprayed with the Ultra solution including the other selected commercialized insecticide solutions such as Carbaryl and Pirimicarb, and also with a water-sprayed control. According to the results, the control effect of Ultra on the adults and immatures was respectively 98.9% and 97.5% after 48hr, and the corresponding values were higher than that of the other tested insecticides (i.e Carbaryl showed 84.6% for adults and 85.6% for immatures; Pirimicarb showed 83.0% for adults and 90.7% for immatures). For the Susceptibility test, LC$_{50}$ value of Ultra showed the lowest as 1.5ppm, the value of Carbaryl and Pirmicarb were 3.7 ppm and 30.4 ppm, respectively. Therefore, the insecticidal effects were better for the newly developed insecticide than the commercialized insecticides.

• Journal of Preventive Medicine and Public Health
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• v.3 no.1
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• pp.47-49
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• 1970

Laboratory susceptibility tests with various insecticides against houseflies(Musca domestica L.) were simultaneously conducted with larvae. As a result of these experment the following conclusion has been obtained. 1. The relative ratio to various insecticidal effects were naled>DDVP>diazinon>${\gamma}-BHC$>malathion>dieldrin>DDT in houseflies larvae. 2. It was noted that resistance to various insecticides in larvae was in proportion to resistance in adults.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.303-310
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• 2015

The diamondback moth, Plutella xylostella, overwinters in some protected areas in Korea. Using a sex pheromone trap, the adults were monitored since the occurrence of the overwintering populations. In Andong, P. xylostella exhibited four adult peaks in a year. Biological characters, such as cold tolerance, insecticide susceptibility, and developmental rate, were analyzed and showed a significant variation among different local overwintering populations. Population genetic variation was assessed with molecular markers, in which the initial high genetic variation among the overwintering populations decreased with the progress of seasons. These results suggests that there may be a significant migration of P. xylostella to decrease the genetic variation among the different local populations that are different in biological characters.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.413-419
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• 2008

The susceptibility of five stink bugs species collected soybean fields in Milyang in 2006 to seven insecticides was evaluated using electric auto-sprayer. The insecticide deltamethirn had the lowest median lethal concentration ($LC_{50}$) of 0.4 to 2.3 ppm regardless of stink bugs species while phenthoate had the highest concentration for one-banded stink bug (Piezodorus hybneri), green stink bug (Nezara antennata), sloe bug (Dolycoris baccarum), and brown marmorated stink bug, (Halyomorpha halys); and fenthion for bean bug (Riptortus clavatus). The average $LC_{50}$ for stink bugs to seven insecticides was lowest at 7.5 ppm for R. clavatus, followed by 16.6 ppm for H. halys, 17.6 ppm for D. baccarum, 19.1 ppm for N. antennata, and 28.4 ppm for P. hybneri. The relative tolerance ratio (TR), which is the TR of 90 percent lethal concentration ($LC_{90}$) of stink bugs to the recommended concentration, was the lowest in fipronil for R. clavatus, P. hybneri and D. baccarum; fenitrothion for N. antennata; and fenthion for H. halys. The relative average TR was lowest at 0.09 for R. clavatus, followed by 0.26 for D. baccarum, 0.30 for N. antennata, 0.37 for P. hybneri, and 0.39 for H. halys. Therefore, insecticides susceptibility was highest for R. clavatus and lowest for P. hybneri while the relative average TR was lowest for R. clavatus and highest for H. halys. Accordingly, it is expected that stink bugs can be effectively controlled with by spraying insecticides in soybean field because the relative average TR value of stink bugs was below 1.0, indicating high susceptibility of stink bugs to insecticides.

• Korean journal of applied entomology
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• v.50 no.1
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• pp.39-46
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• 2011

This study analyzed effects of different sound treatments in frequencies and intensities on digestion and immune physiological processes of the beet armyworm, Spodoptera exigua larvae. Without effect on egg hatch, sound treatments with 100-5,000 Hz at 95 dB suppressed feeding behavior and inhibited a digestive enzyme activity. In addition, two dimensional electrophoresis of midgut luminal proteins indicated a marked difference of the sound-treated larvae. In response to 5,000 Hz at 95 dB, larvae showed a significant decrease in hemocyte nodule formation against fungal challenge along with significant suppression in phospholipase $A_2$ activity in hemocyte and plasma. With increase of sound frequencies, the treated larvae showed an enhanced susceptibility to insecticides. Such sound frequency effect was significantly modulated with different sound intensities. These results suggest that sound treatment may give adverse stress to physiological processes of S. exigua larvae and may be applied to a nonchemical insect pest control.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.380-390
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• 2005

This study was carried out for looking into the status of susceptibility of vinyl house insect pests to insecticides. The Thrips (Thrips palmi and Frankliniela occidentalis), Mites (Tetranychus urticae), Aphids (Aphis gossypii) and Whitefly (Trialeurodes vaporariorum) were captured at various areas where the host crop was 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. The tested insecticides showed good control effect to palm thrips in 2000, but in 2003 showed decrease of effect to them. Western flower thrips showed low susceptibility to neonicotinoids, imidacloprid and thiamethoxam, but high to chlorfenapyr, spinosad, emamectinbenzoate and fipronil. Antibiotic insecticides, abamectin and milbemectin, and chlorfenapyr were very effective on mite control and dicofol still had good effectiveness to it despite of long year use. No aphid species showed resistance to pyrethroid and carbamate insecticides. Relatively new insecticides such as imidacloprid, spinosad, pymetrozine were effective to whitefly, but not were organophosphates, carbamates and pyrethroids.

• The Korean Journal of Pesticide Science
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• v.6 no.2
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• pp.80-86
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• 2002

The activities against Frankliniella occidentalis adults collected at rose greenhouse of 40 commerical insecticides were investigated. Among them 9 insecticides showed over 80% mortality to the adults; chlorfenapyr, chlorpyrifos- methyl, emamectin benzoate, fenthion, fipronil, phenthoate, spinosad, chlorpyrifos+diflubenzuron and furathiocarb+diflubenzuron. Susceptibility of field populations collected from greenhouse rose at 5 locations in 2001 was evaluated against the 9 insecticides selected. There was considerable difference in susceptibility depending on the treated insecticides and the regions from which the populations were collected. Goyang and Gimhae populations showed lower $LC_{50}$(ppm) values then Imsil, Jincheon and Gaangjin populations to all the tested insecticides. The adults of all field populations showed lower $LC_{50}$ values less than 1 ppm to emamectin benzoate, fipronil and spinosad. From these results, we could recommend 5 insecticides, such as emamectin benzoate, fipronil, spinosad, chlorpyrifos+diflubenzuron and furathiocarb+diflubenzuron as effective ones to control the Frankliniella occidentalis field populations.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.194-200
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• 2007

Insecticidal activity of 33 registered insecticides was tested against last nymphal instars and adults of ussur brown katydid (Paratlanticus ussuriensis). All experiments were tested at the recommended concentration of each insecticides by producer. Acephate, chlorpyrifos, diazinon, EPN and fenitrothion which were organophates, and a mixture combined with chlorpyrifos+${\alpha}$-cypemethrin showed 100% mortality of P. ussuriensis. But fipronil showed only 100% mortality in leaf-dipping method. Carbamates insecticidal groups, benfuracarb and furathiocarb were showed over 80% and phenthoate was $60{\sim}80%$ in mortality of P. ussuriensis. Among the mixture, etofenprox+diazinon and esfenvalerate+fenitrothion were showed 60-80% against last nymphal instars of P. ussuriensis. Otherwise, acephate, chlorpyrifos, diazinon, EPN and fenitrothion were showed 100% mortality of P. ussuriensis within only 24 hours after treatment, but there was no effective after then in residual tests with leaves.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.74-79
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• 1996

General esterases were analysed quantitatively and qualitatively to see their role in deltamethrin resistance mechanisms of the diamondback moth, Plutella xylostella L. Selection with 0.1 g of deltamethrin in each generation induced the moth to decrease susceptibility to the insecticide and to increase esterase activities of the fourth instar larvae. Both characters were highly correlated so that the correlation coefficient (r) between LDSo @g) of deltamethrin and esterase activities (~M/min/pg) was 0.9918 (P=0.0082). Nondenaturing PAGE (6%) separated 17 esterase bands from the whole body extracts of the fourth instar larvae. Deltamethrin-selected populations had fewer esterase bands than had the unselected. Four esterase bands (E3, E4, Ell, and E13) were, however, specific to deltamethrin-selected populations.