The insecticidal activities of materialsderived from Dryopteris crassirhizoma Nakai against third instar larvae of three species mosquitoes (Culex pipiens, Aedes albopictus and Anopheles sinnensis) were evaluated using a direct contact mortality bioassay. The methanol extracts of D. crassirhizoma showed 100%, 87.8% and 100% larvicidal activity at 1,000 ppm against Cx. pipiens, Ae. albopictus and An. sinensis, respectively. Hexane fraction showed 100% larvicidal activity three species mosquitoes at 500 ppm after 24 hrs. Purification of the biologically active constituents from the hexane extraction with larvicidal activity was done using silica gel column chromatography. H1 and H3 fractions gave 100% mortality to Cx. pipiens, Ae. albopictus and An. sinensis at 100 ppm. H1 fraction separated with methanol to give a H111 through centrifugation. Fraction of the biologically active constituents from the H3 fraction with larvicidal activity was done using methanol. H31 fraction was determined 100% mortality to Cx. Pipiens, Ae. albopictus and An. sinensis at 50 ppm, respectively. Two fractions were analyzed C14H22O (H111, MW206.0) and C11H14O4 (H31, MW210.08) by GC and GC-MS. D. crassirhizoma derived compounds described herein could be useful for managing filed populations as larvicide of Cx. pipiens, Ae. albopictus and An. sinensis.

The toxicity of red pine needle hydrodistillate, its constituents, and 12 structurally related compounds to third instar larvae of insecticide-susceptible Aedes aegypti and wild Aedes albopictus was examined using a direct-contact bioassay. Results were compared with those of the currently used larvicides fenthion and temephos. The red pine needle hydrodistillate constituents were identified by GC-MS and co-elution of authenticated samples following co-injection. Based on 24 h LC50 values, 3-carene (8.60–9.33 mg/L), limonene (10.34–10.77 mg/L), and thymol (10.65–11.45 mg/L) were the most toxic constituents. The moderate toxicity was produced by (1S)-(–)-α-pinene, p-cymene, geranyl acetate, myrcene, and β -caryophyllene (LC50, 27.62–38.01 and 28.61–39.52 mg/L). Overall, these compounds were less effective than either fenthion (LC50, 0.012–0.022 mg/L) or temephos (LC50, 0.010–0.015 mg/L). In the light of global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment, red pine needle hydrodistillate and the compounds described merit further study as potential larvicides for the control of mosquito populations.

The toxicity of imperatorin (1) and osthol (2) identified in Cnidium monnieri seed and four structurally related compounds to third instar larvae of insecticidesusceptible (KS-CP strain) and field-collected (DJ-CP colony) of Culex pipiens pallens was examined. Results were compared with those of to conventional mosquito larvicide, fenitrothion and temephos. Based on 24-h LC50 values, imperatorin was 1.9, 3.7, 4.2, 12.4, and 15.1 times more toxic than isopimpinellin, isoimperatorin, osthole, xanthotoxin, and bergapten against KS-CP larvae, respectively. Overall, these compounds were less toxic than either fenitrothion or temephos. However, these compounds did not differ in toxicity against larvae from the two Culex strains, even though the DJ-CP larvae exhibited high levels of resistance α-cypermethrin, deltamethrin, chlorpyrifos, fenthion, and chlorfenapyr (resistance ratio, 94-1179). This finding indicates that the isolated compounds and the pyrethroid, organophosphorus, and pyrrole insecticides do not share a common mode of action or elicit cross-resistance.

바퀴(Blattella germanica L.)의 살충제 저항성 기구를 구명하고자 chlorpyrifos와 permethrin 살충제로 누대선ㅂㄹ하여 얻어진 저항성 바퀴를 대상으로 저항성 기작에 관여하는 esterase 활성변화에 관하여 실험한 결과는 다음과 같다. Filter paper test 방법을 통한 esterase-의 활성은 chlorpyrifos와 permethrin 도태계통에서 각각 2.65배, 1.82배로 감수성계통보다 증가하였다. Spectrophotometer 방법을 통한 esterase의 활성은 감수성계통보다 chlorpyrifos 도태계통에서 - 및 -Naphthyl acetate에 대하여 각각 2.34배, 5.28배, permethrin 도태계통에서는 1.48배, 2.2배 증가하였다. 전기영동 실험을 통한 esterase isozyme pattern은 모두 5개의 band가 분리 검출되었다. Rc와 Rp계통에서는 감수성계통에서 뚜렷하게 검출되지 않은 Est-2와 Est-3 band가 검출되었으며, Rp계통에서는 감수성과 Rc계통에서 검출된 Est-5 band가 검출되지 않았다.

초 록 벼멸구의 살충제 저항성 기구를 구명하고자 fenobucarb, carbofuran 및 diazinon으로 벼멸구를 14~18세대 누대 도태하여 얻어진 벼멸구를 대상으로 저항성 기구를 조사하였으며, 얻어진 결과중 acetylcholinesterase(AChE)와 esterase의 활성 변화에 대하여 보고하고자 한다. AChE활성은 fenobucarb선발 계통에서 1.6배 증가하였으나 타 계통에서는 차이가 없었고, 세포내 분포도 mitochondrial fraction에서 70% 이상으로 계통간 차이가 없었다. 반면, AChE감수성은 fenobucarb와 carbofuran선발 계통에서 각각의 공시 살충제에 대하여 12.2배, 5.6배 감소하였으나 diazinon선발 계통에서는 diazoxon에 대하여 1.7배 감소에 그쳤다. Esterase활성은 fenobucarb선발계통에서 5.6~6.8배, carbofuran선발계통에서 6.4~7.8배, diazinon선발계통에서 4.0~4.4배 증가하였다. 벼멸구의 저항성 증가에 다른 요인이 관련됨을 배제할 수 없으나, 본 실험 결과 esterase 활성증가와 AChE감수성 저하라는 두 요인이 상승적으로 작용하여 벼멸구 저항성을 유발하였음을 확인하였다.