Six mosquito species in the Anopheles Hyrcanus group are known as vectors responsible for transmitting vivax malaria in South Korea. In this study, seasonal dynamics of Anopheles Hyrcanus group species and knockdown resistance (kdr) mutations in malaria-endemic sites, Paju and Gimpo, were monitored over two years. In August 2023, all six species were observed simultaneously in one of the Paju collecting sites, and kdr mutations were newly identified in all species except Anopheles kleini. Although Anopheles pullus was revealed as a relatively resistant species among five species populations without kdr mutation via bioassays, there were no critical differences in the voltage-sensitive sodium channel sequence. These findings suggest variability in pyrethroid resistance mechanisms among Anopheles Hyrcanus Group species.

To elucidate the mechanism of pyrethroid resistance in Helicoverpa armigera, the study explored three possibilities based on deltamethrin as a model pyrethroid; 1) the existence of mutations in the target site of deltamethrin, 2) the existence of variation at the genomic level between insecticide-susceptible and resistant strains, 3) differences in gene expression patterns between the strains. Based on these hypotheses, three levels of resistant strains and a susceptible strain as well as nine Korean field populations were used. As results, 1) any point mutations were not detected in sodium channel gene. 2) based on newly set Korean reference genome (GCA_026262555.1), approximately 3,369,837 and 1,032,689 variants (SNPs and Indels) were revealed from genome and ORFs, respectively. However, any specific variants were not found to be highly correlated with the level of insecticide resistance. 3) based on DEG analysis, some of detoxification enzyme genes were differently expressed particularly cytochrome P450 genes. Therefore, H. armigera possibly acquires deltamethrin resistance through a combination of actions, including over-expression of various detoxification enzymes such as CYP3 subfamilies and cuticular proteins.

본 연구는 피레스로이드계 살충제인 퍼메트린이 Heliothis virescens의 중추신경세포의 나트륨채널에 어떻게 작용하는 가를 전기생리학적으 로 관찰하였다. 퍼메트린은 나트륨채널의 꼬리전류(INa-tail)를 지속적으로 증가시켰으며 이러한 비정상적인 나트륨 전류증가가 나방류의 신경계에 과도한 흥분을 일으겨 살충작용을 하는 것으로 생각된다. 이러한 살충작용은 전갈독과 함께 사용했을때 약 8배의 증가가 있었음을 확인하였다. 전 갈독이 살충제의 독성을 강화하는 분자생리학적 기전연구가 계속되면 해충방제에 많은 기여를 할 것으로 생각된다.

본 연구에서는 감귤원에서 초생재배 유무(초생재배 W, 제초제 살포 NW)와 합성피레스로이드계 살포유무(살포 P, 무살포 NP)에 따른 귤 응애의 개체군 동태를 구명하고자 수행되었다. 두 가지 기본적인 가설로 1) 초생재배는 천적의 서식처를 제공하여 천적의 정착을 높이므로 귤응 애의 발생을 감소시키는 요인으로 작용하며, 2) 합성피레스로이드계는 천적을 제거하여 귤응애의 밀도를 증가시키는 요인으로 가정하였다. 관측 된 천적 개체군(주로 이리응애류와 마름응애류)의 발생은 가정에 근거한 기대치와 크게 다르지 않았다. 2011년의 경우 NW+NP 처리구와 W+NP 처리구에서 차이가 있었으나, 2012년 실험에서는 기대치와 관측치가 거의 일치하였다. 전체적으로 약제효과가 뚜렷하게 나타나서 합성 피레스로이드계 살포시 천적이 유의하게 감소하였다. 잡초효과는 엇갈리는 결과를 보였는데, 봄-유래 여름 개체군 대비 가을 개체군의 증가 등을 고려할 때 초생재배를 하는 경우 천적의 발생이 증가하였다. 다만, 합성피레스로이드계 살포구에서 귤응애가 감소하는 비이상적인 결과는 귤응 애의 합성피레스로이드계에 대한 강한 기피성을 전제로 해석할 수 있었다.

Imported 313 cases of Dengue fever and 16 cases of Zika virus disease were reported in the ROK during 2016. Aedesalbopictus has been reported as a major vector mosquito for Dengue and Zika virus. Various class of pesticides havebeen used locally different pesticide class. To investigate the pyrethroid and organophosphate pesticide resistance, genomicDNA was used for Allele-specific PCR (AS-PCR) genotyping of the acethylcholine esterase to detect Gly119Ser mutationsand kdr gene to detect Phe1534Cys mutations. Detoxification enzyme activities were assessed using Ae. albopictus fromYeosu and Jeju. Activities of four detoxification enzymes eg., glutathione S-transferase (GST), Non specific esterases (α-naphthylacetate and β-naphthyl acetate), and cytochrome C oxidase were determined for each Ae. albopictus strain. In our studies,Ae. albopictus showed only susceptible sequences for AchE and kdr. Activity of cytochrome P-450 and non specific esterasewas higher in a field population than a laboratory strain, except for GST. This study might be helpful to understandthe insecticidal susceptibility and resistant for effective vector mosquito control program.

Aedes albopictus is an important vector for yellow fever, dengue fever, chikungunya fever and Zika virus. This mosquitohas been exposed to organophosphates and pyrethroids in Republic of Korea for a long time. Using the direct contactmortality bioassay, susceptibility strain and two field populations of Ae. albopictus from Busan, and Damyang. Insecticidalproperty were indicated to RR ratio values (Resistant ratio to strain of susceptibility) of LC50 (Midian Lethal concentration)to organophosphats and pyrethroids. Genomic DNA was used for Allele-specific PCR (AS-PCR) genotyping of the acethylcholineesterase to detect Gly119Ser mutations and kdr gene to detect Phe1534Cys mutations. Detoxification enzyme activitiesof Ae. albopictus from Busan and Damyang were assessed using microplate enzyme activity assays. Activities of fourdetoxification enzymes eg., glutathione S-transferase(GST), Non specific esterases (α-naphthyl acetate and β-naphthyl acetate),and cytochrome C oxidase were determined for each Ae. albopictus strain. This study might suggest that Ae. albopictuscontrol programs should be prepared for the management of organophosphate and pyrethroid insecticide resistance.

The activities of three class, five acaricides (Permethrin, Deltamethrin, Fenitrothion, Chlorpyrifos, Imidacloprid) againstHaemaphysalis longicornis nymph, a major vector for Severe Fever with Thrombo cytopenia Syndrome (SFTS) and Lymedisease. The ticks distribute at vast open fields and various kind of habitats. Five acaricides were applied to ticks collectedform four areas(Gapyeong, Paju, Chuncheon, Wonju) to confirm the effect of acaricide. This areas was the area whereSFTS disease occurred and a large nember of ticks were collected. As a result, All areas is the most acaricidal effectto Deltamethrin. And two areas(Gapyeong, Paju) has the lowest acaricidal effect to Imidacloprid and two area(Chuncheon,Wonju) has the lowest acaricidal effect to Permethrin. Futher study will need to compare the acaricidal efficacy of theremaining seven province.

Anopheles sinensis is an important vector for Plasmodium vivax and thus has been targeted with pyrethroids in Republic of Korea. Using the direct contact mortality bioassay, two field populations of An. sinensis from Ganghwa-gun and Goyang-si were characterized for their resistance to pyrethroids with RR ratio values (Resistant ratio to imidacloprid) of 125.6 to 203.8 folds and 80.0 to 120 folds, respectively. Genomic DNA was used for Allele-specific PCR (AS-PCR) genotyping of the sodium channel genes to detect L1014S mutations. The homozygous susceptible Leu/Leu genotype in Ganghwa-gun and Goyang-si was 5.0% and 11.3% and the resistance genotypes were 95.0% and 88.7%, respectively. The homozygous Phe/Phe resistance genotype was the most prevalent as 35.4% in Ganghwa-gun and 44.0% in Goyang-si. Hence, this study suggests that malaria vector control programs should be prepared for the management of pyrethroid insecticide resistance.

Anopheles sinensis is an important vector for Plasmodium vivax and thus has been targeted with pyrethroids in Republic of Korea. Using the direct contact mortality bioassay, two field populations of An. sinensis from Paju-si and Yeoncheon-gun were characterized for their resistance to pyrethroids with RR ratio values (Resistant ratio to imidacloprid) of 96.8 to 167.2 folds and 34.2 to 98.4 folds, respectively. Genomic DNA was used for Allele-specific PCR (AS-PCR) genotyping of the sodium channel genes to detect L1014S mutations. The homozygous susceptible Leu/Leu genotype in Paju-si and Yeoncheon-gun was 3.3% and 37.1% and the resistance genotypes were 96.7% and 62.9%, respectively. The homozygous Phe/Phe resistance genotype was the most prevalent as 45.0% in Paju-si and 31.5% in Yeoncheon-gun. Hence, this study suggests that malaria vector control programs should be prepared for the management of pyrethroid insecticide resistance.

The cotton bollworm, Helicoverpa armigera (Hübner) is a serious agricultural pest which has evolved resistance against many chemical classes of insecticides. This species has evolved resistance to the synthetic pyrethroids across its native range and is becoming a truly global pest, after establishing in Brazil and having been recently recorded in North America. A chimeric cytochrome P450 gene, CYP337B3, has been shown to detoxify to fenvalerate and cypermethrin. The CYP337B3 gene has now been detected in different populations around the world, and is even found in South America. This gene is likely to have arisen independently in different geographic locations, probably through selection on pre-existing diversity, and there is ongoing movement of these alleles around the world. The alleles found in Brazil are those most commonly found in Asia, suggesting a potential origin for the incursion into the Americas. This information should be taken into account when devising control strategies for this invasive pest, both in its native range and in the Americas

The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), is an ectoparasitic pest that feeds on humans as well as other mammals. We investigate that point mutations on the voltage-sensitive sodium channel are associated with the resistance to pyrethroids. Two point mutations (V419L and L925I) in the voltage-sensitive sodium channel (VSSC) α-subunit gene have been identified in deltamethrin-resistant bed bugs. L925I, located the intracellular loop between IIS4 and IIS5, has been previously found in a highly pyrethroid-resistant populations of whitefly. V419L, located in the IS6 transmembrane segment, is a novel mutation. To establish a population-based genotyping method as a molecular resistance monitoring tool, a quantitative sequencing (QS) protocol was developed. Frequency prediction equations were generated from the plots by linear regression, and the signal ratios were shown to highly correlate with resistance allele frequencies (r2 > 0.993). In addition to QS, the filter contact vial bioassay (FCVB) method was established and used to determine the baseline susceptibility and resistance of bed bugs to pyrethroids. A pyrethroid-resistant strain showed > 9375- and 6990-fold resistance to deltamethrin and λ-cyhalothrin, respectively. Resistance allele frequencies in different bed bug populations predicted by QS correlated well with the FCVB results, confirming the roles of the two mutations in pyrethroid resistance. Taken together, employment of QS in conjunction with FCVB method should greatly facilitate the detection and monitoring of pyrethroid resistant bed bugs in the field.

본 연구는 나리 인편자구 포장정식 시 재배시설에 따른 바이 러스 감염률 등을 조사하여 포장 구근생산체계를 확립하고자 하 였다. 맹아률은 비가림하우스 및 망실하우스에서 높았으며, 품종 별로는 ‘Yelloween’이 ‘Star Gazer’보다 높았고 ‘Yelloween’ 의 망실하우스에서 맹아률은 90.3%였다. 총생체중 및 구근특성 도 ‘Yelloween’이 ‘Star Gazer’보다 높았으며 ‘Yelloween’ 노 지 정식구에서 총생체중은 15.8g이었으며 구중은 10.7g으로 가장 양호하였다. 진딧물 비래의 최성기는 5월이었고 노지 38마리 에 비해 비가림 및 망실에서 8마리, 2마리로 월등히 낮았으며, 바이러스 이병률은 CMV가 LSV보다 높았으며 노지에서 CMV 이병률은 17.8%로 비가림 및 망실보다 4배 이상 높았다. Pyrethroid처리는 250mg • L-1이상에서 바이러스 방제효과가 있 었다.

The green peach aphid (Myzus persicae) is a cosmopolitan pest of agricultural and horticultural crops and causes serious economic damages. M. persica has rapidly developed resistance to a wide variety of insecticides, including pyrethroids. Target site insensitivity mechanism mediated by two mutations (L1014F and M918T) on the para-type voltage-sensitive sodium channel (vssc) is mainly responsible for pyrethroid resistance. To predict the vssc resistance allele frequency, quantitative sequencing (QS) protocol was established. Frequency prediction equations generated from the plots of signal ratios and amplification critical time showed a high correlation coefficient (r2>0.993), indicating its high accuracy in prediction. QS results revealed that the kdr-type L1014F mutation is only present in Pyeongchang strain. No field strains of M. persicae possessed the super-kdr type M918T mutation. However, a novel M918L mutation was found by genotyping approach. The allele frequencies of M918L and L1014F were 0% to 53% in populations examined, and the level of M918L mutation frequency was closely related with pyrethroid resistance. Therefore, QS-based detection of M918L mutation frequency should faciltate the monitoring of pyrethroid resistance in the field.

Two point mutations (V419L and L925I) in the voltage-sensitive sodium channel (VSSC) α-subunit gene have been identified in deltamethrin-resistant bedbugs. To predict resistance allele frequencies of sodium channel mutations (V419L and L925I) in bedbugs at a population level, we developed quantitative sequencing (QS) protocol. The signal ratios between resistant and susceptible nucleotides were generated from sequencing chromatogram and plotted against the corresponding resistance allele frequencies. Linear regression coefficients of the plots were close to 1 (r2 = 0.9928 and 0.9998), suggesting that the signal ratios are reliable correlated with the resistance allele frequencies. To enable on-site monitoring of pyrethroid resistance in bed bugs, residual contact vial (RCV) bioassay method was established and used to determine median lethal concentration (LC50) values to deltamethrin for various bed bug strains. Resistance allele frequencies in these bedbug strains predicted by QS were correlated well with the RCV bioassay results, confirming the roles of two mutations in pyrethroid resistance. Taken together, employment of QS in conjunction with RCV bioassay should greatly facilitate resistance monitoring of bedbugs in the field.

Comparative insecticidal efficiency between compounded pyrethroids and its preparations cooperated with several synergists was studied. As main components, Group A contained Permethrine Phthalthrine, Group B contained Permethrine Furameth rine and Group C contained Phthalthrine Dichlorvos. As synergists Piperonyl Butoxide (P.B.O.), N-Octylbicycloheptene dicarboximide (MGK-264), Octachlorodipropylether (S-421) was cooperated in each group. These preparations was treated to either Blattella G. or Musca D. for comparing about insecticidal efficiency[Knock-down rate (KT_(50), KT_(90)) and cumulative mortaility(percent/hrs)]. When the synergists was added to each Group, the insecticidal efficiency was improved. The most potent synergists was P.B.O. and the potency was decreased in the rank order of S-421$gt;MGK-264. The more the concentration of synergists was increased, the more the insecticidal effciency was improved. The rank order was 1:5≥1:4$gt; 1:3 in all three groups. The mortality (percent) according to time was similar to either KT_(50), or KT_(90-). Knock-down rate was appropriate parameter for the indicator about potency.