본 연구에서는 GC-NPD/MS를 이용하여 농산물 중 국내 사용금지 고독성 유기인계 살충제 phosphamidon의 잔류 분석법을 확립하였다. 대표 농산물은 배추, 고추, 감귤, 현미 및 콩을 사용하였고, acetone으로 추출된 phosphamidon은 n-hexane 및 dichloromethane 액-액 분배법을 순차적으로 이용하고 silica gel 흡착크로마토그래피법으로 정제하여 GC-NPD/MS 의 분석시료로 사용하였다. Phosphamidon의 정량분석을 위한 최적 GC-NPD 분석조건을 확립하였으며, 정량한계(LOQ)는 0.02 mg/kg 이었다. 각 대표 농산물에 대해 정량한계, 정량한계의 10배, 50배 및 100배 수준에서 회수율을 검토한 결과, 모든 처리농도에서 84.9~100.7% 수준의 회수율을 나타내었으며, 반복 간 변이계수(CV)는 최대 4.9%를 나타내어 잔류분석 기준인 회수율 70~120% 및 분석오차 10% 이내를 충족시키는 만족한 결과를 도출하였으며, GC/MS SIM을 이용하여 실제 농산물 시료에 적용하여 재확인 하였다. 이상의 결과로 신규 phosphamidon의 GC-NPD/MS 분석법은 검출한계, 회수율 및 분석오차 면에서 국제적 분석기준을 만족하는 신뢰성이 확보된 정량분석법으로 사용 가능할 것이다.

국내에 서식중인 청개구리의 배아를 활용하여 농약류 3종의 독성평가를 위해 FETAX(Frog Embryo Teratogenesis Assay-Xenopus) 기법에 따라 청개구리(Hyla japonica)의 배아를 배양하면서 Benomyl(살균제), Carbofuran(살충제), Thiobencarb(제초제)의 효과를 probit 분석법으로 조사하였다. 그 결과, Benomyl, Carbofuran, Thiobencarb의 농도에 의존하여 유생의 체장 길이는 감소하고 치사율과 기형율은 증가하였다. Benomyl, Carbofuran, Thiobencarb의 teratogenic concentration(EC50)은 각각 1.00, 0.58, 4.75mg/L을 나타내어 Carbofuran이 기형유발에 가장 민감하게 반응하였으며, embryo lethal concentrations(LC50)은 7.04, 28.71, 16.12mg/L을 나타내어 Benomyl이 가장 낮은 농도에 서 배아를 치사하는 것으로 나타났다. Teratogenic index(TI=LC50/EC50)는 Benomyl 7.04, Carbofuran 49.50, Thiobencarb 3.39를 나타내어 TI값이 모두 기형유발물질로 판단하는 기준인 1.5 이상을 나타내어 시험에 사용된 농약류 3종은 최기형성 물질로 판단되며 Carbofuran이 가장 강력한 최기형성물질로 작용함을 알 수 있었다.

본 연구는 농산물 중 2019년 기준신설 예정농약 Broflanilide에 대한 공정시험법을 개발하고자 수행하였다. Broflanilide는 meta-diamide계 살충제로 중추신경계 억제성 신경전달물질인 gamma-aminobutyric acid (GABA) 수용 가이드라인(2016)’에 적합한 수준임을 확인하였다. 개발된 시험법은 낮은 검출한계 및 정량한계, 우수한 직선성, 회수율 실험을 통한 정확성과 정밀성, 재현성 등이 입증되 어 농산물 중 broflanilide의 잔류검사를 위한 공정시험법 으로 활용되기에 적합한 것으로 판단된다.

한국에 서식하는 모기종 중 흔히 볼 수 있는 금빛숲모기(Aedes vexans nipponii)는 미국에서 West Nile Virus의 주요 매개종으로 알려져 있다. 또한 지카바이러스를 포함한 30가지가 넘는 바이러스의 매개체로 작용할 가능성이 있다고 보고되고 있다. 이들을 방제하기 위한 방법으로 화학적 방제는 매우 효과적일 수 있으나 지속적인 살충제 사용은 저항성 문제를 불러일으킬 수 있다. 현재 금빛숲모기의 경우 이에 대한 관련 연구가 거의 이루어지지 않은 상황이다. 본 연구는 근연종인 흰줄숲모기와 이집트숲모기의 연구를 참고하여 합천에 위치한 축사에서 채집된 금빛숲모기 샘플로부터 기존에 알려진 Acetylcholinesterase-1(Ace-1)의 target site mutation인 G119, T506과 knockdown resistance(kdr) target site mutation인 V410, L982, S989, I1011, L1014, V1016, T1520, I1532, F1534, D1763을 분석하였다. 분석결과, 저항성을 가진 개체는 발견되지 않았으며 mutation site에 관해 정확히 알려진 바가 없으므로 bioassay를 통한 추가조사가 필요할 것으로 판단된다.

A residual contact vial plus water (RCVpW) bioassay method was established to monitor insectiside resistance in field populations of the melon thrips, Thrips palmi. Resistance level against six major insecticides were evalutated in five regions to test applicability of RCVpW as an on-site resistance monitoring tool. Reduced mortality in response to six test insecticides were exhibited compared to the RDA susceptable strain showing 100 % mortality, indicating different degree of resistance. An apparently reduced mortality to emamectin benzoate and chlofenapyr was observed in some field populations, suggesting uneven distribution of resistance to these insecticides in field populations. In addition, spinosad resistance was high and widely distributed in the test regions. Synergistic bioassay revealed that cytochrome P450-mediated metabolic factor is involved in spinosad resistance in the Korean population.

One of major mechanisms of insecticide resistance is the reduced susceptibility caused by mutations on the main target sites, such as sodium channel and acetylcholinesterase. Bioassay is a useful method to diagnose insecticide resistance of mosquitoes; however, it is hard to establish regional/annual resistance database based on bioassay. Recently, various markers of mutation and copy number variation have been identified through insecticide mechanism studies. Thus, molecular detection of resistance based on the resistance marker is now feasible, which can be readily implemented as a novel resistance monitoring tool to complement or replace the conventional bioassay method. In Korea, the density of vector mosquitoes native to the subtropical areas has increased due to climate change. Therefore, it is required to establish an efficient resistance monitoring system based on molecular markers to facilitate the construction of a nation-wide resistance map for more effective control of mosquitos. In addition, alternative insecticides should be introduced to the areas where mosquitoes develop high levels of resistance to maximize control efficacy against resistant populations

소나무재선충병의 나무주사는 살선충제를 중심으로 실시되어 왔으며, 매개충인 솔수염하늘소와 북방수염하늘소의 방제는 주로 항공방제나 지상방제를 통하여 이루어졌다. 본 연구에서는 나무주사를 통하여 매개충 (솔수염하늘소)을 방제하기 위한 연구로 Abamectin+Acetamiprid ME, Thiamethoxam DC 약제의 나무주사시 솔수염하늘소의 약효발현농도, 처리 후 기간별 효과(2017년~2018년)를 검토하였다. 실내 발현농도 시험에서는 Acetamiprid, Thiamethoxam LC50 value는 각각 0.102ppm, 0.083ppm 으로 나타 났으며, 야산(포장)에서 Abamectin+Acetamiprid ME, Thiamethoxam DC 처리구의 100.0% 치사 소요일 수는 처리 90일 후 11.0일, 9.4일, 처리 360일 후 11.6일, 10.0일로 나타나서 두 약제 모두 3월 처리시 다음해에 발생하는 매개충 (솔수염하늘소) 방제까지 가능함을 확인 할 수 있었다.

The Asian corn borer, O. furnacalis (Crambidae) and the old world bollworm, H. armigera (Noctuidae) simultaneously cause ear damage in corn in Suwon area. It has been assumed that the second generation of larvae of both insects is responsible for the damage. We, therefore, studied proper spray timing of insecticide in order to reduce the damage. A waxy corn hybrid cultivar, Ilmichal, was sown directly on four plots of a field at April 10, April 20, May 4, and May 18, 2018, respectively. A sodium channel blocker, indoxacarb, was sprayed eight times at 3- or 4-day intervals around the silking stage of corn in each sowing plot. At ear harvest time of each plot, we investigated damaged ratio and length of ear, and the numbers of both insect species. The significantly effective spray timings on reduction of ear damage were the sprays at June 29 and July 2 in the plot sown at April 10, the sprays from July 2 to 13 in the April 20-sown plot, the sprays from July 2 to 19 in the May 4-sown plot, and the sprays at July 19 in the May 18-sown plot, respectively. The damage level was positively related to the insect number. The result indicated that the spray at the silking stage of corn was effective on reduction of ear damage. It was assumed that occurrence time of neonate larvae of the insects at silking stage cause the damage, based on the experimental results using screened pots inoculated with the two species.

농업사회는 지속적인 농지면적 및 농촌인구 감소, 빠른 고령화로 인하여 일손이 매우 부족한 상황에서 하우스 시설면적의 증가와 새로운 외래해충의 발생증가 등으로 인하여 작물보호제의 의존도가 점점 높아지고 있다. 작물보호제 시장은 1980년도에는 성분량으로 16,132톤 1,348억원 출하 판매되었으며, 2017년에는 20,043톤 1조 5,048억원 시장으로 발전하였다. 작물보호시장 중 살충제 시장은 1980년 6,407톤 572억원 출하 판매되었으며, 2017년에는 6,282톤 5,707억원 시장으로 성장하였다.

Residual contact vial (RCV) method was used to monitor insecticide resistance in field populations of the melon thrips, Thrips palmi. Median lethal doses (LD50) at 8 h post-treatment of six insecticides (chlorfenapyr, cyantraniliprole, cypermethrin, dinotefuran, emamectin benzoate and spinosad), which are commonly used for T. palmi control, were determined at 8 h post-treatment using a susceptible RDA strain. The diagnostic doses for on-site resistance monitoring of the six insecticides, which were determined as two-fold higher doses of LD90 for the RDA strain, were in the range of 0.299 to 164,25 μg-1cm2. To test the applicability of RCV for T. palmi, insecticide resistance levels in three field populations (Gyeonggi; GG_AS, Chungbuk; CB_CJ, Jeonbuk; JB_KJ) were evaluated. Field populations showed reduced mortality (0-50% mortality) to spinosad, cypermethrin, cyantraniliprole and emamectin benzoate, that they have different degree of resistances to these insecticides. In particular, all test field populations exhibited 0% mortality to spinosad, suggesting wide spread of spinosad resistance in the field. Moreover, no detectable mortality to emamectin benzoate was observed in JB_KJ strain, suggesting uneven distribution of emamectin benzoate resistant population of T. palmi. To provide more precise information on resistance profiles and distribution in T. palmi populations, it would be necessary to conduct a large scale resistance mapping for broad geographical regions.

The cotton bollworm, Helicoverpa armigera is one of the most polyphagous and cosmopolitan pest species in world wide including Korea. It also showed high level of resistance against various types of insecticide. To set the integrated resistant management program, first, we tried to identify the insecticide resistant mechanism via transcriptome analysis of coding and non-coding RNAs using 4 strains (Australian susceptible and resistant strains, Korean and Brazilian resistant strains, additional a sub-lethal dose insecticide treatment in Korean resistant strain). From the illumina based RNAseq data sets with genome information, some resistant involved detoxification genes and long non-coding RNAs were discovered. Second, following molecular markers were developed from resistant strain specific amino acid substitution from those candidate genes. Third, functionally identified genes’ markers were applied in field populations using some molecular diagnostic tools such as LAMP (loop mediated isothermal amplification). Now additional functional analysis is going on for these un-characterized candidate genes and long non-coding RNAs.

Growing resistance to insecticides, especially pyrethroids, poses an increased risk for insect control world-wide. Thus, alternative compounds are urgently needed. Accordingly, my laboratory has been investigating synthetic materials, as well as natural products, which are an attractive source of new chemistries. We have examined the insecticidal and synergistic activity of new compounds using Drosophila melanogaster and the mosquitoes Aedes aegypti and Anopheles gambiae as model insects. In addition, we have also been investigating the modes of action of experimental molecules in various physiological preparations. Natural product research included thymol, which was toxic to Ae. aegypti adults at doses (3-50 μg/mg) similar to published toxicities for the cabbage looper larvae, Trichoplusia ni. On homomultimeric Anopheles gambiae GABA receptor-chloride channel complex expressed in Xenopus laevis oocytes, thymol acts as a positive allosteric modulator, increasing the potency and maximal effectiveness of applied GABA, consistent with the sluggish paralysis it elicits in exposed insects. Other studies investigated matrine; a bioactive component extracted from Sophora flavescens that is used as the main ingredient in Chinese bio-pesticidal products. Matrine caused flaccid paralysis in headless fourth instar larvae of Ae. aegypti (50% paralysis in 5 hours at 8 ppm) and was toxic to adult females by contact (topical LD50 = 258 ng/mg). Adult toxicity was increased about 2-fold by pretreatment with the mono-oxygenase inhibitor, piperonyl butoxide. Interestingly, this compound was much less effective on D. melanogaster in either glass contact or feeding bioassays. Adult mosquito knockdown was rapid, with little or no expression of hyperactivity or hyperexcitability. Matrine (ca. 1 mM) had effects similar to thymol on expressed An. gambiae GABA receptors, and reduced EPSP amplitude at the Musca domestica neuromuscular junction, without any evidence of neuroexcitation or membrane depolarization. These physiological actions are sufficient to explain the whole animal intoxication by matrine, but require relatively high concentrations to manifest themselves. Other studies tested a series of potassium channel blockers, including 1-((2-chlorophenyl)diphenylmethyl)-1H-pyrazole (TRAM-34), 11-dansylaminoundecanoic acid (DAUDA), and 5-hydroxydecanoic acid (5-HDC) as insecticides and synergists of pyrethroids. We also evaluated the action of these compounds in patch clamp recordings of engineered HEK cells expressing Anopheles gambiae Kv2.1 channels. Patch clamp studies revealed that fatty acid compounds without functional groups in the alkyl chain (e.g., decanoate, DAUDA) yielded a more potent blocking action on Kv2.1 currents than substituted fatty acids (e.g., 5-HDC). Also, in comparison to 2-methoxy-N-((1-phenylcyclopentyl)methyl)benzamide (2S-65465), a known Kv2 channel blocker (IC50 = 100 nM), decanoate and DAUDA were 6-fold and 12-fold less active, respectively, as blockers of potassium current. TRAM-34 was the least potent inhibitor tested in patch clamp studies (IC50 = 30 uM). When tested on D. melanogaster CNS, the compounds typically gave an initial increase in firing rate, followed by a decrease, both effects at micromolar concentrations. Various toxicity assays showed the same potency ranking as that obtained through patch-clamp recordings, indicating a possible connection between channel block and whole organism effects. In order to possibly improve the insecticidal activity of the fatty acids, we synthesized derivatized analogs (e.g., methyl esters) presumed to better penetrate the cuticular barrier, but activity did not improve. Finally, in contrast to a published patent, we found that fatty acids did not show much synergism with pyrethroids. The implications of this work for resistance management will be discussed.

소나무재선충병의 방제를 위한 나무주사는 살선충제를 사용하여 예방적인 측면에서 이루어 졌다. 본 연구는 소나무에 살충제를 나무주사하여 약제를 소나무 전체에 침투 이행시킨 후 우화한 매개충이 후식하는 과정에서 약제가 포함된 신초를 섭식하게 되면 소화중독으로 교미 및 산란 전에 살충시킴으로서 매개충을 방제하고자 실시하였 다. 이러한 살충제 나무주사 방법은 신초를 후식하는 하늘소류만을 소화중독에 의해 살충시키는 방법으로 기존의 항공방제에 비해 환경에 대한 영향을 최소화 할 수 있다. 살충제 나무주사에 가장 적합한 약제 선발을 위해 실내에서 Neonicotinoid계 살충제 7종을 각 2,000배로 희석한 후 솔수염하늘소에 2㎕를 경구투입하여 살충효과를 평가한 결과 Clotianidin SL, Thiamethoxam DC이 소화중독에 의한 살충효과가 가장 우수하였으며, 이들 살충제를 야외에서 소나무에 나무주사 후 가지에 망대를 설치하고 솔수염하늘소를 접종하여 살충력을 검정한 결과 Thiamethoxam DC가 살충력이 가장 우수한 것으로 판단되었다. 또한 현장적용을 위해 잣나무림에 나무주사후 산란유인목을 설치하여 무처리구와 비교한 결과 살충제 나무주사 시험지의 산란유인목에서는 산란이 이루어지지 않아 현장방제에 적용 가능성을 확인할 수 있었다.

도시림, 생활림, 가로수, 도시공원 등 국민들의 일상생활을 하는 구역이나 장소에 위치한 생활권 수목 식재지에서의 농약 살포는 농약 살포자의 농약 노출 문제뿐만 아니라 농약의 살포 후 생활권 수목과 접촉하는 불특정 시민들도 지속적인 농약 노출이 문제가 될 수 있다. 본 연구에서는 생활권 수목의 관리를 위해 관행적으로 가장 많이 사용 살포되는 살충제인 Fenitrothion을 회양목에 살포하고 일정시간별로 손 노출량, 잎 잔류량, 호흡 노출량을 측정 한 뒤, 위해성 평가 수식(MOS; margin of safety)을 이용하여 체중별 안전 노출시간을 분석하였다. 그 결과, 살포된 Fenitrothion의 손을 통한 전이량이 급격하게 떨어지고 호흡노출량이 측정되지 않는 48시간 이전 까지는 농약노출에 대한 주의가 필요할 것으로 판단되었다.

Toxicities of Carbofuran showed different patterns by three application methods, Drench(as systemic effect), Leaf dipping(as contact and systemic effects) and Topical(as contact effect) applications. LC50 dropping pattern was L-shape in Drench, low slope line in Topical and intermediate of them in Leaf dipping. Drench application was the most Carbofuran treatment method to Brown planthoppers. Dropping patterns of LC50 were almost same between resistant and susceptible strains. The checking time of Carbofuran toxicity was suggested to be 2nd day after application by SD analysis of mortality. Resistance ratios were peak on 3rd day after application in Drench, 4th day(Susceptible) and 5th day(Resistant) in Leaf dipping and showed steady increase line pattern in Topical application.

꽃노랑총채벌레는 국화, 장미, 고추, 토마토 등 여러 작물의 잎, 꽃, 과실을 흡즙 및 산란을 통해 피해를 주며 토마토반점위조바이러스(TSWV)와 국화줄기괴저바이러스(CSNV) 등을 매개한다. 재배작기, 환경, 품종등에 따라 총채벌레류의 발생과 피해가 다양하게 나타나는 국화는 총채벌레류 및 매개 바이러스병으로 인해 약 20∼30%의 생산량이 감소된다. 또한 총채벌레류에 대한 약제저항성 계통의 출현이 지속적으로 보고되어 살충제의 교호사용에 주의가 필요한 방제가 어려운 해충 중 하나이다. 살충력이 높은 살충제를 선정하기 위하여 시판하는 국화 총채벌레류 등록 살충제 Acetamiprid, Acetamiprid+Spinetoram, Acrinathrin, Benfuracarb, Buprofezin+Thiamethxam, Chlorfenapyr+ lothiandin, Chlorfenapyr+Imidacloprid, Emamectin+Benzoate, Imidacloprid, Thimethoxam 10종을 꽃노랑총채벌레에 살포 한 결과 유효성분으로 Pyrroles계인 Chlorfenapyr를 함유한 살충제의 살충력이 가장 높았다. 총채벌레류의 화학적 방제 시 Chlorfenapyr가 함유한 살충제를 사용하는 것이 효과적이다.

Grapholita molesta (Busck) (Lepidoptera: Tortricidae) is an important pest of apple, peach, plum, etc. Growers use synthetic chemical insecticides to manage this pest, but G. molesta have developed an insecticide resistance. As botanical insecticides have been rarely studied against G. molesta, we assessed relative toxicity of azadirachtin (azatrol 10 mL/L) in comparison with λ-cyhalothtrin (6.7 mL/20L) in residual assays using both glass scintillation vial coated with the insecticides and apple fruits dipped in the insecticide solutions against first instar larvae (<5 h old) of G. molesta. Azadirachtin showed highest corrected morality of 96.7% at 8h followed by 63.3% in λ-cyhalothtrin in the scintillation vial. On apple dipped in the insecticide solutions, no significance in corrected mortality was found between azadirachtin and λ-cyhalothtrin. Thus azadirachtin can be used as a botanical insecticide for the management of G. molesta.