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

• Parasites, Hosts and Diseases
• /
• v.58 no.1
• /
• pp.99-102
• /
• 2020

Two-point mutations (V419L and L925I) on the voltage-sensitive sodium channel of bed bugs (Cimex lectularius) are known to confer pyrethroid resistance. To determine the status of pyrethroid resistance in bed bugs in Korea, resistance allele frequencies of bed bug strains collected from several US military installations in Korea and Mokpo, Jeollanamdo, from 2009-2019 were monitored using a quantitative sequencing. Most bed bugs were determined to have both of the point mutations except a few specimens, collected in 2009, 2012 and 2014, having only a single point mutation (L925I). No susceptible allele was observed in any of the bed bugs examined, suggesting that pyrethroid resistance in bed bug populations in Korea has reached a serious level. Large scale monitoring is required to increase our knowledge on the distribution and prevalence of pyrethroid resistance in bed bug populations in Korea. Based on present study, it is urgent to restrict the use of pyrethroids and to introduce effective alternative insecticides. A nation-wide monitoring program to determine the pyrethroid resistance level in bed bugs and to select alternative insecticides should be implemented.

• Korean Journal of Agricultural Science
• /
• v.50 no.4
• /
• pp.829-840
• /
• 2023

Various chemical pesticides are used to control diamondback moths, Plutella xylostella, which are agricultural pests that occur in cruciferous crops worldwide and cause economic losses. However, due to pesticide misuse, resistance to P. xylostella is consistently reported domestically and internationally. Therefore, we aimed to monitor and map regional resistance to devise efficient and economical control methods for P. xylostella in Korea. This study selected eight highly used insecticides among those registered against P. xylostella. P. xylostella were collected from three cities in the Gyeonggi and Yeongnam Provinces to evaluate insecticide resistance. As a result of experiments with populations collected from Yeoju, Gyeonggi Province, resistance ratios were 114.88, 54.75, 119.00, and 64.00 times higher than the susceptible population with methoxyfenozide, indoxacarb, cyantraniliprole, and fluxametamide, respectively. The resistance ratios of the Yongin population in Gyeonggi Province were 166.33 times with cyantraniliprole and 195.25 times with fluxametamide higher than the susceptible population. The Pocheon population in Gyeonggi Province showed a resistance ratio 283.23 times higher than methoxyfenozide. As a result of experiments with populations collected from Gimhae and Sangju, Yeongnam Province, the resistance ratios of the Gimhae population were 80.97, 138.00, and 89.50 times higher than the susceptible population with methoxyfenozide, cyantraniliprole, and fluxametamide, respectively. Meanwhile, the resistance ratios of the Sangju population were 85.83, 224.67, and 303.25 times higher than the susceptible population with methoxyfenozide, cyantraniliprole, and fluxametamide, respectively. The Yeongnam Province Tongyeong population showed a resistance ratio 367.28 times higher to methoxyfenozide.

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

• Korean journal of applied entomology
• /
• v.60 no.2
• /
• pp.167-173
• /
• 2021

Sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an insect pest with sucking mouth part and globally attacks diverse crops and vegetables. Since first reported in 1998, it is now widely spread in many regions in Korea. Due to insecticide resistance, it is necessary for optimal control of the whiteflies to select effective insecticides with precise insecticide resistance monitoring. In this study, B. tabaci individuals were collected from 12 regions in 7 provinces of Korea from June to September in 2020. Using these field populations, insecticide resistance levels were monitored using a residual contact bioassay along with molecular markers. Bioassay results revealed that B. tabaci possessed high levels of resistance to five insecticides exhibiting different modes of action: dinotefuran, spinosad, emamectin benzoate, chlorfenapyr, and bifenthrin. In addition, quantitative sequencing in target sites of organophosphate and pyrethroid insecticides revealed that point mutations reached to saturated or near-saturated levels across the country. This suggests that insecticide resistance management is required for effective control of B. tabaci populations in Korea.

• The Korean Journal of Pesticide Science
• /
• v.6 no.4
• /
• pp.264-270
• /
• 2002

Studies on the resistance monitoring of green peach ahpid, Myzus persicae, its development pattern by artificial selection with imidacloprid and cross-resistance were carried out to develope resistance management strategy. Resistance ratios of M. persicae collected at Hwachon and Dunnae among 5 locations in alpine cultivation area appeared to be high as 37.2 and 16.5, respectively. Resistance of aphid to imidacloprid developed slowly up to 20 time selection, and after that it grew quickly. Imidacloprid-resistant aphid strain showed low cross-resistance ratios(<10) to most of organophosphates, carbamates, and mixed insecticides except pirimicarb(487.8), but high ratios to acetamiprid(143.0) which is one of the neonicotinoids like imidacloprid, and pyrethroids such as deltamethrin(14.9), flucythrinate(12.9) and halothrin(15.9).

• Parasites, Hosts and Diseases
• /
• v.58 no.5
• /
• pp.543-550
• /
• 2020

Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.

• Korean Journal of Environmental Biology
• /
• v.35 no.4
• /
• pp.557-565
• /
• 2017

For our survey of insecticidal resistance of Palm thrips (Thrips palmi Karny), we established the discriminating time (DT) and concentration (DC) of nine insecticides, and we conducted a bioassay about seven local populations via leaf-dipping methods. The discriminating times of the recommended concentration (RC) were 24 h at emamectin benzoate EC and spinetoram SC, 48 h at chlorfenapyr EC, 72 h at spinosad SC, cyantraniliprole EC, acetamiprid WP, dinotefuran WG, imidacloprid WP and thiacloprid SC after treatment. The DC estimated the concentration which showed the difference within the mortalities of these local populations. The DCs were emamectin benzoate EC $0.013mg\;L^{-1}$ (RC, $10.8mg\;L^{-1}$), spinetoram SC $0.125mg\;L^{-1}$ (RC, $25.0mg\;L^{-1}$), chlorfenapyr EC $0.25mg\;L^{-1}$ (RC, $50.0mg\;L^{-1}$), spinosad SC $0.083mg\;L^{-1}$ (RC, $50.0mg\;L^{-1}$) and cyantraniliprole EC $5.0mg\;L^{-1}$ (RC, $50.0mg\;L^{-1}$), and DCs of neonicotinoids were their RCs, that is, acetamiprid WP (RC, $40.0mg\;L^{-1}$), dinotefuran WG (RC, $20.0mg\;L^{-1}$), imidacloprid WP(RC, $50.0mg\;L^{-1}$) and thiacloprid SC (RC, $50.0mg\;L^{-1}$). From our investigation into the resistance of the local populations with DT and DC application, the neonicotinoid insecticides have shown a high resistant level for all the local populations, and the other insecticides have demonstrated low or non-resistance. In the use of neonicotinoid insecticides to control Palm thrips, one must take caution. As a result, the establishment of DT and DC in the single dose bioassay method was helpful for surveying the insecticide response dynamics and the development of an insecticide resistance management strategy.

• Korean journal of applied entomology
• /
• v.38 no.1
• /
• pp.53-57
• /
• 1999

Simple diagnostic kits for monitoring insecticide susceptibility of beet armyworm, Spodoptera exigua (Hiibner) were developed and applied to the field populations. The operation of the kits was based on the correlations between enzyme activities of esterase (EST) and acetylcholinesterase (AChE) and the insecticide susceptibilities. Four different kinds of diagnostic kits (ED, EM, AD, and AM) were designed and classified by diagnostic enzymes (E for esterases and A for acetylcholinesterase) and inhibitors (D for dichlorvos and M for monocrotophos). Diagnostic inhibitor concentrations were 1 mM for ED, 10 mM for EM, 100 mM for AD, and 100 mM for AM. Resistant larvae which were not inhibited by the diagnostic amounts of insecticides developed positive staining (red color), but susceptible~ s howed negative (no color). An insect was used for both EST and AChE diagnostic kits, but different in their samples: hemolymph for EST and the head for AChE. These four diagnostic kits were applied to 1 1 different populations which showed variations of insecticide susceptibilities. Four kits were different in the capability discriminating the insecticide susceptibilites according to insecticides: ED to bifenthrin, AD to methomyl, and ED and AM to chlorpyrifos-methyl. These diagnostic devices can be used for insecticide-resistance management program for this insect pest. It also provide a technical guide to insect pest management for farmers, directors, and researchers.