椿叶花椒果实精油对两种蚊虫的生物活性及成分分析

为筛选环保型的植物源灭蚊活性物质, 研究了椿叶花椒 Zanthoxylum ailanthoides 果实精油对白纹伊蚊Aedes albopictus和致倦库蚊Culex pipiens quinquefasciatus成蚊的熏杀活性, 并测试了精油对这两种蚊幼虫的毒杀效果。此外, 采用GC-MS分析了该精油的化学成分。 结果表明：在102.145 μg·cm^-3熏杀剂量下, 精油对白纹伊蚊和致倦库蚊成蚊的KT50值分别为2.788和3.505 min, 24 h致死率分别为100%和97.53%。该精油对白纹伊蚊和致倦库蚊4龄幼虫的LC50值分别为45.237和20.759 mg·L^-1。从椿叶花椒果实精油中共鉴定出14种化合物, 其中2-十一酮为主要成分, 相对含量为89.86%。结果说明椿叶花椒果实精油对两种蚊虫均有明显的杀虫活性, 具有开发成植物源灭蚊剂的潜力。     

小蓬草精油对两种蚊虫的毒杀活性和成分分析

【目的】明确小蓬草Conyza canadensis ( L.) Cronq.精油的杀虫潜力及其活性成分。【方法】通过浸虫法和密闭熏蒸法测试了小蓬草精油对白纹伊蚊Aedes albopictus和致倦库蚊Culex pipiens quinquefasciatus幼虫及成蚊的毒杀活性, 并利用气相色谱 质谱联用仪（GC-MS）对精油的挥发性成分进行了定性分析。【结果】 小蓬草精油对白纹伊蚊1-4龄期幼虫及蛹的24 h LC50值分别为25.01, 45.88, 56.94, 64.60和346.23 μg/mL; 对致倦库蚊幼虫1-4龄期幼虫及蛹的24 h LC₅₀值分别为9.16, 8.65, 32.12, 43.68和197.83 μg/mL。在剂量分别为48, 64, 80, 96, 112和128 μg/cm3时, 小蓬草精油对白纹伊蚊成蚊的KT₅₀值分别为28.81, 22.31, 20.38, 17.05, 13.92和9.74 min; 对致倦库蚊的KT50值分别为34.90, 32.97, 23.97, 19.60, 15.20和10.34 min。 24 h熏蒸对白纹伊蚊和致倦库蚊成蚊的LC50值分别是75.46和99.19 μg/cm³。小蓬草精油的GC MS定性分析共分离鉴定出31种化合物, 其中单萜类物质6种, 倍半萜烯类物质17种, 含氧萜烯类6种。【结论】结果表明小蓬草精油对这两种蚊虫的毒杀活性较高, 具有深开发潜力。     

一摸香叶精油对致倦库蚊的生物活性及其成分分析

参照“农药登记卫生用杀虫剂的室内药效评价/驱避剂GB/T 17322.10—1998”,研究了一摸香鲜叶的水蒸汽蒸馏精油对致倦库蚊的驱避作用;参照“电热片蚊香的室内药效测定方法GB 13917.5—1992”,测试了该精油对致倦库蚊成蚊的熏杀效果;采用浸液法测试了其对致倦库蚊幼虫及蛹的毒杀活性;并用GC-MS测试分析了其化学成分.结果表明：一摸香叶精油在1.5 mg·cm^-2剂量下对实验室饲养的未吸血致倦库蚊雌成蚊的驱避100%保护时间为(6.54±0.17) h,对成蚊的熏杀24 h LC₅₀值为6.895 μg·cm^-3,对成蚊的熏蒸KT₅₀值为6.46 min (熏蒸剂量为11.850 μg·cm^-3),对Ⅳ龄期幼虫的24 h毒杀LC₅₀值为119.020 μg·ml^-1.精油中共鉴定出17种化合物,占该精油挥发性成分总量的97.4%.说明一摸香叶精油对致倦库蚊具有显著的驱避作用和极强的毒杀活性.     

BsC3-41杀蚊幼制剂对蚊幼虫毒杀效果研究

通过以BsC3-41杀蚊幼制剂对3种蚊幼虫进行生物活性测定和野外灭蚊试验,结果表明:该制剂对致乏库蚊Culex fatigans Wiedemann的毒杀效果最好、对中华按蚊Anopheles sinensis Wiedemann次之、对白纹伊蚊Aedes albopictus Skuse的效果较差,24小时LC50值分别为0.2025μg/ml、2.5363μg/ml和59.7302μg/ml.野外水体灭蚊使用3ml/m2的浓度防治淡色库蚊效果可达98.88%～100.00%,使用10ml/m2的浓度防治中华按蚊效果可达96.81%～100.00%,使用200ml/m2的浓度防治白纹伊蚊效果达到90.64%以上.     

苦杏仁精油的熏蒸杀虫活性研究

采用三角瓶密闭熏蒸法测定了苦杏仁精油对家蝇、白纹伊蚊、粘虫以及玉米象的熏蒸杀虫活性,结果显示:苦杏仁精油对各试虫均有较强的熏蒸杀虫活性,其中含HCN的精油对家蝇、白纹伊蚊、粘虫以及玉米象的LC50分别为3.09、0.63、4.63、12.03μL/L;除去HCN的精油对家蝇、白纹伊蚊、粘虫以及玉米象的LC50分别为3.53、0.52、4.08、23.46μL/L;熏蒸的时间效应试验结果表明,含有HCN的苦杏仁精油和不含HCN的苦杏仁精油对供试试虫的熏杀速度均较快,其中白纹伊蚊的反应最快,其次为家蝇、粘虫、玉米象.除玉米象外苦杏仁精油中所含的微量HCN对试虫的熏蒸活性影响不大,且2种处理的精油对同种试虫的致死中时差别范围不超过10 min.实验结果表明,苦杏仁精油可作为新型的杀虫活性物质,为苦杏仁精油作为植物源杀虫剂提供了依据.     

埃及伊蚊浓核病毒(AaeDV)对致倦库蚊的致病性研究

致倦库蚊(Culex quinquefasciatus)是西尼罗病毒(West Nile virus,WNV)、圣路易斯脑炎病毒等重要的媒介。蚊浓核病毒(Mosquito densovirus,MDV)是特异性感染蚊类的病毒,对蚊虫具有明显的致病性。为研究MDV对致倦库蚊的致病效应,我们使用不同浓度埃及伊蚊浓核病毒(Aedes aegypti densovirus,AaeDV)感染致倦库蚊不同发育阶段的幼虫、蛹与成蚊,测定其感染率与死亡率,结果证实AaeDV对致倦库蚊1~2龄幼虫、3~4龄幼虫、蛹和雌雄成蚊的感染率分别为93.33%±2.49%、66%±3.74%、2.67%±0.94%、23.33%±3.40%和24.00%±1.63%,感染率与其发育阶段有关而与性别无关。AaeDV对幼虫的杀伤效果具有剂量依赖性,且与发育阶段有关,在1×1011拷贝/mL浓度下,新孵化龄幼虫和3~4龄幼虫的死亡率高达95.33%±0.74%和61.67%±2.07%。因此AaeDV对致倦库蚊具有生物防制的潜在价值。     

球形芽孢杆菌TS-1丙酮粉对七种蚊虫的毒力测定

用乳糖-丙酮沉淀法制备的球形芽孢杆菌Bacillus sphaericus,TS-1菌粉对七种蚊虫幼虫进行了毒力测定,以淡色库蚊,致倦库蚊最为敏感,其LC₅₀分别为8.1μg/L(1.79×10²cfu/ml),8.9μg/L(1.96×10²cfu/ml),三带喙库蚊敏感性较淡色库蚊差13倍,2龄白纹伊蚊和中华按蚊分别差20和600倍;黄斑伊蚊,二株埃及伊蚊剂量高达10⁵—10⁶cfu/ml相差1,000—10,000倍以上几乎无效.本文结合B.t.I.标准生物测定方法,对毒力测定中检查时间、数据、虫龄、虫数、饲料等问题进行了讨论.     

广东城镇地区防治蚊虫试验

本文以20%除虫脲(即灭幼脲Ⅰ号)胶悬剂在广东省番禺县大岗镇地区进行防治蚊幼虫试验.结果表明,根据蚊种及其孽生地类型可施用0.1—1.0ppm的浓度,对白纹伊蚊、致倦库蚊和骚扰阿蚊幼虫都有比较好的效果,而且持效也比较长.经过每15—20天喷洒一次,防治面积共564m²,基本上控制了蚊虫的发生数量.通过诱蚊箱的监测,7—9月份处理区各月份的成蚊密度均比对照区低.在使用剂量的范围内,除虫脲对鲩鱼、鳙鱼、食蚊鱼和蝌蚪安全.其杀虫作用是抑制幼虫的生长发育和变态.     

大链壶菌对白纹伊蚊及几种其它贵州蚊虫的杀灭作用的观察(英文)

采用大链壶菌在实验室内对白纹伊蚊及其它几种贵州蚊虫的幼虫进行杀灭试验。白纹伊蚊的感染率为25—89％,而致倦库蚊的感染率可达90—100％。实验结果为大链壶菌的宿主记录新增加一个属和五个种。     

四川省三种蚊虫对拟除虫菊酯的敏感性

1986—1987年以浸渍法或接触筒法,在成都、平武、珙县(或宜宾),用中华按蚊An.sinensis,致倦库蚊Cx.pipiensquinquefiscitatus和白纹伊蚊Ae.albopictus,分别对溴氰菊酯、二氯菊酯、DDT进行敏感性测定。结果成都致倦库蚊对二氯菊酯的LC50为0.0481ppm,显示抗性的存在;平武(0.0058ppm)、珙县(0.0081ppm)仅为区分剂量(0.048ppm)的1/5—1/8,说明比较敏感。成都、平武、珙县所测LC50平均值(0.021ppm)都高于海南省(0.0062ppm)、浙江省(0.019ppm)、云南省(0.0088ppm)、吉林省(0.0056ppm)和广西省(0.0062ppm),说明四川省致倦库蚊对二氯菊酯的敏感…     

Susceptibility of mosquitoes in central Taiwan to natural infections of Dirofilaria immitis

From October 1997 to September 1998, 3085 Culex quinquefasciatus (Say) (Diptera: Culicidae), 584 Cx. tritaeniorhynchus (Giles) (Diptera: Culicidae), 392 Cx. annulus (Theobald) (Diptera: Culicidae), 374 Aedes albopictus (Skuse) (Diptera: Culicidae) and 102 Armigeres subalbatus (Coquillet) (Diptera: Culicidae) were collected and examined for Dirofilaria immitis (Leidy) (Spirurida: Filariidae) infection. However, only Cx. quinquefasciatus and Ae. albopictus were infected, with a prevalence of 4.28% and 3.74%, respectively. The intensity of D. immitis found in Ae. albopictus (3.43 larvae/mosquito) was higher than that found in Cx. quinquefasciatus (2.89 larvae/mosquito). After being fed with canine blood containing 7500 microfilariae (mf) per mL, Cx. quinquefasciatus ingested approximately two times as many mf as Ae. albopictus (mean of 31.73 in comparison to 16.47). However, almost three times as many third-stage infective larvae developed in Ae. albopictus as in Cx. quinquefasciatus (mean of 3.25 as compared with 1.10), with a vector efficiency index (VEI) of 19.73 and 3.47, respectively. The results showed that Cx. quinquefasciatus and Ae. albopictus served as natural vectors of D. immitis in central Taiwan. Although Ae. albopictus was more efficient for heartworm transmission, Cx. quinquefasciatus may play a more prominent role on the transmission of dirofilariasis in central Taiwan.     

Laboratory evaluation of methanolic extract of Atlantia monophylla (Family: Rutaceae) against immature stages of mosquitoes and non-target organisms

Methanolic extracts of the leaves of Atlantia monophylla (Rutaceae) were evaluated for mosquitocidal activity against immature stages of three mosquito species, Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti in the laboratory.Larvae of Cx. quinquefasciatus and pupae of An. stephensi were found more susceptible, with LC50 values of 0.14 mg/l and 0.05 mg/l, respectively. Insect growth regulating activity of this extract was more pronounced against Ae. aegypti, with EI50 value 0.002 mg/l. The extract was found safe to aquatic mosquito predators Gambusia affinis, Poecilia reticulata, and Diplonychus indicus, with the respective LC50 values of 23.4, 21.3, and 5.7 mg/l. The results indicate that the mosquitocidal effects of the extract of this plant were comparable to neem extract and certain synthetic chemical larvicides like fenthion, methoprene, etc.     

Aedes albopictus (Diptera: Culicidae) in Rome: experimental study of relevant control strategy parameters

Since 1997, Aedes albopictus has colonised and then rapidly invaded the city of Rome (Italy) and its peripheral areas. Presently, the control of this mosquito in Italy relies mainly on larvicidal treatment of street storm sewer catch basins with the organophosphate temephos. We have therefore obtained baseline data on the susceptibility to temephos of the Roman Ae. albopictus population by laboratory bioassays on F1 fourth-instar larvae following standard WHO protocols. Estimated lethal concentrations were 0.014 mg/l (LC50) and 0.022 mg/l (LC90) indicating a lack of resistance to this compound. The persistence of temephos in sewer catch basins was evaluated by follow-up of catch basins treated with a dose of 1.5 mg of active ingredient. Mosquito larvae were recovered in 10% and 50% of the treated basins at 9 and 18 days posttreatment, respectively. In order to understand the relative contribution of this larval habitat to adult populations, we conducted a survey in the Zoo of Rome to estimate the larval density of mosquitoes breeding in sewer catch basins. A complete census of a 16.5 ha area mapped 243 catch basins, but only 25 (10.3%) contained water; of the latter 8 (32.0%) hosted mosquito larvae. All positive catch basins contained larvae of Culex pipiens, which were associated with Culiseta longiareolata and/or Ae. albopictus in 6 and 3 cases, respectively. A longitudinal survey of one catch basin over 4 months showed that the mean larval density of Ae. albopictus was markedly lower than that of Cx pipiens and Cs. Iongiareolata, ranging between 0 and 1.3 larvae/dip as compared to 0-33.2 and 0-22.7 larvae/dip, respectively. However, adult densities of Ae. albopictus in this area estimated during the same period with 20 ovitraps showed consistently high values (proportion of positive ovitraps around 100%). These preliminary observations suggest that whenever alternative larval biotopes other than sewer catch basins are widely available, they might be more productive and/or preferred substrates to catch basins for Ae. albopictus breeding.     

致倦库蚊对登革Ⅱ型病毒的中肠感染屏障作用

为探讨致倦库蚊对登革Ⅱ型病毒的中肠感染屏障作用,通过病毒分离、逆转录聚合酶链反应、透射电镜等技术进行了相关研究。结果表明：吸食感染性血液后,登革Ⅱ型病毒能侵染白纹伊蚊中肠上皮细胞并大量复制,但不能侵染致倦库蚊中肠上皮细胞。以上研究证明致倦库蚊对登革Ⅱ型病毒存在中肠感染屏障。     

Insecticidal activities of leaf essential oils from Cinnamomum osmophloeum against three mosquito species

The larvicidal activities of leaf essential oils and their constituents from six chemotypes of indigenous cinnamon (Cinnamomum osmophloeum Kaneh.) trees were evaluated against three mosquito species. Results of larvicidal tests demonstrated that the leaf essential oils of cinnamaldehyde type and cinnamaldehyde/cinnamyl acetate type had an excellent inhibitory effect against Aedes albopictus larvae, and their LC(50) values in 24h were 40.8 microg/ml (LC(90)=81.7 microg/ml) and 46.5 microg/ml (LC(90)=83.3 microg/ml), respectively. Results of the 24-h mosquito larvicidal assays also showed that the effective constituents in leaf essential oils were trans-cinnamaldehyde and benzaldehyde and that the LC(50) values of these constituents against A. albopictus larvae were below 50 mug/ml. In addition, cinnamaldehyde type leaf essential oil and trans-cinnamaldehyde have also exhibited great larvicidal performance against Culex quinquefasciatus and Armigeres subalbatus larvae. Comparisons of mosquito larvicidal activity of trans-cinnamaldehyde congeners revealed that alpha-methyl cinnamaldehyde, benzaldehyde, and trans-cinnamaldehyde exhibited strong mosquito larvicidal activity.     

First report of the oriental mosquito Aedes albopictus on the West African island of Bioko,Equatorial Guinea

The invasive oriental mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) was detected on Bioko Island for the first time in November 2001. It was found to be well established breeding in artificial containers at Planta, near Malabo, the capital of Equatorial Guinea. Associated species of mosquito larvae were Aedes aegypti (L.), Ae. africanus (Theobald), Culex near decens Theobald, Cx. duttoni Theobald, Cx. quinquefasciatus Say, Cx. tigripes De Grandpré & De Charmoy, Eretmapodites quinquevittatus Theobald and Mansonia africana (Theobald). This is the third tropical African country to be invaded by Ae. albopictus, which has recently spread to many parts of the Americas and Europe--with vector competence for dengue, yellow fever and other arboviruses. In the Afrotropical environment, it will be interesting to monitor the ecological balance and/or displacement between introduced Ae. albopictus and indigenous Ae. aegpyti (domestic, peri-domestic and sylvatic populations).     

Susceptibility of ten species of mosquito larvae to the parasitic nematode Romanomermis iyengari and its development

Ten species of mosquitoes (Diptera: Culicidae) from five genera were exposed to preparasites of the tropical mermithid nematode species Romanomermis iyengari (Welch) (Nematoda: Mermithidae), a strain isolated in 1978 from Pondicherry. By exposing mosquito larvae during the second instar, nematode infection was invariably lethal, the rate being highest in Culex sitiens Wiedemann (95%) followed by Cx. quinquefasciatus Say (90%), Aedes aegypti (L.) (79%), Anopheles subpictus Grassi (64%), Ae. albopictus (Skuse) and Armigeres subalbatus Coquillett (62%), Cx. tritaeniorhynchus Giles (57%), Mansonia annulifera (Theobald) (46%), An. stephensi Liston (40%) and An. culicifacies Giles (36%). When fourth-instar larvae were exposed, the infection was highest in Ar. subalbatus (66%), followed by An. stephensi (52%), Cx. quinquefasciatus (47%), Ae. aegypti and An. subpictus (42%), Ae. albopictus (30%), An. culicifacies (29%), Cx. sitiens (24%), Cx. tritaeniorhynchus (19%) and Ma. annulifera (8%), with 2-45% of infected culicines surviving to adulthood. The parasitic phase of the nematode lasted 5-7 days in all the host species, yielding 1.1-3.2 parasites per II instar and 1.1-2.5 parasites per IV instar. The overall output of parasites per 100 mosquito larvae (infected + uninfected) was highest for Ae. aegypti when mosquitoes were exposed during II instar (2.53 parasites/larva) and for Ar. subalbatus when mosquitoes were exposed during IV instar (1.65/larva), and lowest for Ma. annulifera exposed during IV instar (0.09/larva). For routine laboratory culture of R. iyengari it is convenient to employ Cx. quinquefasciatus as the host yielding 90-190 parasites/100 larva.