Laboratory evaluation of toxicity of 16 insect repellents in aerosol sprays to adult mosquitoes

Sixteen commercial insect repellents (6 botanical and 10 synthetic organic products) in spray formulations were evaluated in the laboratory for adult knockdown (KD) and mortality of laboratory-reared female Aedes aegypti, Aedes albopictus, and Anopheles quadrimaculatus. All tested products produced significant posttreatment KD and 24 h mortality of all 3 mosquito species. In our study, the synthetic organic repellents induced faster KD and KD of higher magnitude in adult mosquitoes than the botanical product repellents except geraniol-based MosquitoSafe. All tested formulations except 2 botanical repellent products caused 100% 24 h mortality of Ae. aegypti and all but 1 caused 100% 24 h mortality of Ae. albolpictus and An. quadrimaculatus.     

Laboratory evaluation of 18 repellent compounds as oviposition deterrents of Aedes albopictus and as larvicides of Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus

Among 18 experimental skin repellent compounds tested at five concentrations in the laboratory as oviposition deterrents against Aedes albopictus. 12 compounds showed significant activity, with median effective dose values ranging from 0.005 to 0.052%. The test compounds also were evaluated in the laboratory as larvicides against laboratory-reared 4th instars of Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus with the same concentrations employed for the oviposition deterrency tests against Ae. albopictus. Larval mortality data at 24 and 48 h after treatment indicated that 12 test repellents caused larval mortalities in the range of 67 to 100% against An. quadrimaculatus, 10 compounds induced 55-100% larval mortalities of Ae. aegypti, whereas larval mortality caused by 9 compounds ranged from 74 to 100% against Cx. quinquefasciatus. These mortality data did not fit the linear model of the statistical analysis. However, multiway analysis of variance of these data showed that the repellent compounds, concentrations used, species of mosquitoes, and exposure times affect the degree of larval mortalities.     

Repellents and other personal protection strategies against Aedes albopictus

Five chemical repellents, a controlled-release repellent formulation, Avon Skin-So-Soft bath oil and permethrin-impregnated clothing fabric were assayed for personal protection against bites of Aedes albopictus. On skin the chemical repellents provided significant (P = 0.05) protection from biting; however, Ae. albopictus was more sensitive to the repellents than the standard, Ae. aegypti. Two experimental repellents provided 6-7 h protection from bites, 25% deet in ethanol provided greater than 8 h protection, a controlled-release formulation containing 35% deet provided greater than 10 h protection, and the Avon product provided 0.64 h protection from bites. Permethrin-treated fabric provided complete protection from mosquito bites through 0-5 washings. Repellent products containing greater than or equal to 12% deet should provide satisfactory protection against Ae. albopictus; the use of permethrin-impregnated clothing should provide additional protection.     

Evaluation of cyclopoid copepods for Aedes albopictus control in tires

Six species of cyclopoid copepods in New Orleans were tested for biological control of Aedes albopictus larvae in discarded tires. Six to 8 weeks after introduction, Diacyclops navus, Acanthocyclops vernalis, Mesocyclops ruttneri and Mesocyclops edax reduced the number of Ae. albopictus larvae by 83, 90, 95 and 96%, respectively. Macrocyclops albidus and Mesocyclops longisetus were the most effective species. Six to 8 weeks after introduction, Macrocyclops albidus reduced Ae. albopictus larvae by 99%. Three months after introduction Macrocyclops albidus reduced Ae. albopictus larvae by 100%, and Mesocyclops longisetus reduced Ae. albopictus larvae by 99.8%. Macrocyclops albidus and Mesocyclops longisetus were equally effective at eliminating Ae. aegypti and Ae. triseriatus larvae.     

六种驱蚊药驱蚊效果试验研究

六种药品对白纹伊蚊的驱避试验表明,8小时内均具很好的效果(96.4～100%)。002及001号在10小时内仍很好,12小时内002号保护效果仍很高(85.7%),OLE TIME 14小时仍有较高的药效(96.4%)。综合比较其效果为:OLE TIME>002号>蚊怕水>001号>舒乐>BAYER,有效观察时间8分钟左右为宜。     

氨与避蚊胺缔合对白纹伊蚊行为影响的研究

目的 探讨人体引诱物氨与驱避剂避蚊胺（DEET）之间存在的缔合作用,并研究该缔合作用对蚊虫驱避活性的影响.方法 用Y型嗅觉仪分别测定氨、DEET、氨与DEET缔合物对白纹伊蚊的行为反应.结果 氨的浓度为10 mg/L时,对白纹伊蚊有明显的引诱作用,1000和100 mg/L时有微弱引诱作用;DEET的浓度为1000和0.1 mg/L时,对白纹伊蚊有微弱驱避作用,其他浓度作用不明显;浓度为1 mg/L的氨与浓度为1 mg/L的DEET等比例混合物,对白纹伊蚊具有明显的驱避作用;浓度为1000和0.1 mg/L的DEET与同等浓度的氨等比例缔合后,既无驱避效果,也无引诱效果.结论 氨与DEET存在缔合作用,且该缔合作用能增强白纹伊蚊的驱避行为反应.通过研究人体引诱物与驱避剂的缔合作用为驱避机制研究提供新的思路.     

Adult repellency and larvicidal activity of five plant essential oils against mosquitoes

The larvicidal activity and repellency of 5 plant essential oils--thyme oil, catnip oil, amyris oil, eucalyptus oil, and cinnamon oil--were tested against 3 mosquito species: Aedes albopictus, Ae. aegypti, and Culex pipiens pallens. Larvicidal activity of these essentials oils was evaluated in the laboratory against 4th instars of each of the 3 mosquito species, and amyris oil demonstrated the greatest inhibitory effect with LC50 values in 24 h of 58 microg/ml (LC90 = 72 microg/ml) for Ae. aegypti, 78 microg/ml (LC90 = 130 microg/ml) for Ae. albopictus, and 77 microg/ml (LC90 = 123 microg/ml) for Cx. p. pallens. The topical repellency of these selected essential oils and deet against laboratory-reared female blood-starved Ae. albopictus was examined. Catnip oil seemed to be the most effective and provided 6-h protection at both concentrations tested (23 and 468 microg/ cm2). Thyme oil had the highest effectiveness in repelling this species, but the repellency duration was only 2 h. The applications using these natural product essential oils in mosquito control are discussed.     

孳生地治理对控制白纹伊蚊效果的研究

目的观察蚊虫孳生地治理控制白纹伊蚊的效果。方法在试验区共青森林公园游乐区采取各种方法对白纹伊蚊孳生地进行治理;对照区内燃机研究所不采取任何防治措施。实验采用诱蚊诱卵器和CO2诱蚊灯监测白纹伊蚊幼虫和成蚊密度,评价其控制效果。结果在孳生地治理后白纹伊蚊幼虫和成蚊密度逐步下降,在2～3周后幼虫和成蚊相关密度指数皆控制在35以下,密度下降率皆〉50％。结论孳生地治理可有效控制白纹伊蚊的密度。     

Laboratory and field evaluations of the insect repellent 3535 (ethyl butylacetylaminopropionate) and deet against mosquito vectors in Thailand

The insect repellents 3535 (ethyl butylacetylaminopropionate or IR3535) and deet (N,N-diethyl-3-methylbenzamide) were prepared as 20% solutions in absolute ethanol and evaluated for repellency against many mosquito species in Thailand under laboratory and field conditions using human subjects. In the laboratory, 0.1 ml was applied per 30-cm2 of exposed area on a volunteer's forearm (0.66-0.67 mg active ingredient [AI]/ cm2), whereas in the field, volunteers' legs (from knee to ankle, with a surface area of about 712-782 cm2) were treated with 3 ml per exposed area (0.76-0.84 mg AI/cm2). In the laboratory, both IR3535 and deet showed equal repellency (P > 0.05) for 9.8 and 9.7 h against Aedes aegypti, for 13.7 and 12.7 h against Culex quinquefasciatus, and for 14.8 and 14.5 h against Cx. tritaeniorhynchus, respectively. Anopheles dirus was significantly less sensitive to IR3535 than to deet (P < 0.05), with a mean protection time of 3.8 and 5.8 h, respectively. Under field conditions, both IR3535 and deet provided a high degree of protection against various mosquito vectors ranging from 94 to 100% during the test periods. Both repellents provided a high level of protection for at least 8 h against Ae. albopictus and for at least 5 h against Cx. gelidus, Cx. tritaeniorhynchus, Cx. quinquefasciatus, Mansonia dives, Ma. uniformis, Ma. annulata, Ma. annulifera, Anopheles minimus, and An. maculatus. This study clearly documents the potential of IR3535 for use as a topical treatment against a wide range of mosquito species belonging to several genera.     

Field evaluation of deet, Repel Care, and three plant based essential oil repellents against mosquitoes, black flies (Diptera: Simuliidae) and land leeches (Arhynchobdellida: Haemadipsidae) in Thailand

Diethyl methyl benzamide, or deet, a commercial plant-based repellent (Repel Care), and essential ils from 3 species of plants (finger root rhizomes, guava leaves, and turmeric rhizomes), steam distillated and formulated as insect repellents, were evaluated in the field on human volunteers against hematophagous mosquitoes, black flies, and land leeches in Thailand. Field trials were conducted against wild mosquitoes in Bang Bua Thong District, Nonthaburi Province, and in the Thap Lan National Park Headquarters, Nadee District, Pranchinburi Province; anthroophilic black flies (Diptera: Simuliidae) at the Forestry Fire Control Station in Doi Inthanon National Park, Chomthong district, Chiang Mai Province; and land leeches (Arhynchobdellida: Haemadipsidae) in the Khao Yai National Park, Pak Chong District, Nakhon Ratchasima Province. The 3 experimental plant-based essential oil formulations as well as Repel Care and deet provided complete protection from mosquito landing and biting for up to 9 h (duration of the experiment). Similar results were obtained with the 5 products against black flies, providing 100% protection for 9 h but 96-82% protection after 10 and 11 h posttreatment. The 5 repellent products also provided 100% protection against land leeches for at least 8 h. Thi is the 1st report of repellency of plant-based repellents against black flies and land leeches in Thailand. The identification and availability of inexpensive sources of plant-based oils, i.e., finger root rhizomes, guava leaves, and turmeric rhizomes providing long-lasting repellency against blood-sucking organisms are promising leads into commercial production of relatively safe and effective repellents.     

茴香醛对蚊虫嗅觉行为的影响研究

目的 探讨茴香醛对蚊虫嗅觉行为的影响.方法 在风洞系统内测试茴香醛不同剂量诱导的白纹伊蚊行为反应及对宿主定向行为的影响;在密闭空间中,分别以0.013～0.250 μg/cm3剂量的茴香醛处理白纹伊蚊24～96 h后测定其感受、定向寄主的能力.结果 在风洞系统内,茴香醛单一化合物其剂量3.1％～99.0％对白纹伊蚊均有一定的引诱作用,而与宿主气味并存时,只有高剂量(99.0％)对宿主定向行为有较高的抑制率(85.4％).白纹伊蚊在0.050～0.250 μg/cm3剂量茴香醛气味空间处理24～96 h后对其正常感受宿主气味的能力有显著的抑制作用,随处理时间延长、剂量升高抑制效果增强,但低于此剂量则没有抑制作用.结论 茴香醛单一化合物对蚊虫具有引诱性,但与宿主气味并存时,对蚊虫正常感受宿主气味的能力具有一定的抑制作用.     

石香薷精油对白纹伊蚊的生物活性研究及其成分分析

目的测定石香薷（Moslem chinensis Maxim）精油对白纹伊蚊（Aedes albopictus）的生物活性,分析石香薷精油的化学成分,为开发植物源蚊虫控制剂提供研究基础。方法水蒸汽蒸馏法提取石香薷精油;采用浸液法测定精油对白纹伊蚊4龄期幼虫及蛹的毒杀活性;采用人体局部涂肤法测试其对成蚊的驱避活性;通过气相色谱-质谱联用法分析石香薷精油的化学成分。结果 （1）石香薷精油对4龄期幼虫及蛹的24hLC50值分别为78.820和122.656μg/ml;（2）涂抹1.5mg/cm^2的纯精油,对成蚊有（2.330±0.167）h的完全保护时间,6h后仍然有56%的保护率;（3）从精油中共检出44种化合物,鉴定出39种,占总量的98.67%。主要成分有：对-聚伞花素（23.17%）、香荆芥酚（16.83%）、百里香酚（14.92%）、2-异丙基-4-甲基茴香醚（12.89%）、桉树脑（8.48%）、石竹烯（3.96%）、α-石竹烯（3.16%）和乙酸瑞香酯（2.71%）。结论石香薷精油对白纹伊蚊幼虫及成蚊均有较强的生物活性,具有从中发现新的灭蚊天然活性化合物和研发成环保型蚊虫控制剂的潜力。     

Repellent activity against Aedes aegypti (L.) of formulas based on natural vegetable extracts or synthetic active agents

A comparison of 5 commercial mosquito repellents was made on adult male and female volunteers in laboratory trials. The products tested in forms of cream or lotion included 4 natural oil formulations (containing citronella, clover, eucalyptus, geranium, lavender, peppermint, sandalwood, thyme, etc.) and 1 synthetic chemical repellent containing 10% KBR 3023). Natural oil products showed essentially poor or no repellency against Ae, aegypti: the protection times were less than or equal to 1 hour. Only the synthetic repellent based on KBR 3023 provided satisfactory defence to human volunteers.     

Mosquito larvicidal activity of botanical-based mosquito repellents

The larvicidal activity of 4 plant essential oils--innamon oil, lemon eucalyptus oil, sandalwood oil, and turmeric oil--previously reported as insect repellents was evaluated in the laboratory against 4th instars of Aedes albopictus, Ae. aegypti, and Culex pipiens. Sandalwood oil appeared to be the most effective of the larvicides, killing larvae of all 3 mosquito species in relatively short times. The values of LT50 and LT90 at the application dosage (0.2 mg/ml) were 1.06 +/- 0.11 and 3.24 +/- 0.14 h for Ae. aegypti, 1.82 +/- 0.06 and 3.33 +/- 0.48 h for Ae. albopictus, and 1.55 +/- 0.07 and 3.91 +/- 0.44 h for Cx. pipiens, respectively. Chemical compositions of these essential oils were also studied, and the lavicidal activity of their major ingredient compounds was compared with that of each of the essential oils. The acute toxicity of the 4 essential oils to fathead minnows was also evaluated. The safe use of these natural plant essential oils in future applications of mosquito control was discussed.     

蛋白质和氨基酸对2种蚊虫产卵选择的影响

目的评价不同蛋白质和氨基酸对我国2种重要媒介蚊虫淡色库蚊和白纹伊蚊雌蚊产卵选择的影响,为新型蚊虫诱卵器的研制提供理论支持。方法在室内测定淡色库蚊和白纹伊蚊对不同种类蛋白质和氨基酸溶液的产卵趋性。结果淡色库蚊怀卵雌蚊偏好在较高浓度的鱼蛋白胨溶液(1000和100mg/L)和酵母浸膏溶液(1000mg/L)中产卵,而10mg/L浓度的鱼蛋白胨溶液能显著引诱白纹伊蚊产卵;苯丙氨酸溶液在1000、100和10mg/L3个实验浓度下均能显著引诱淡色库蚊和白纹伊蚊产卵。结论鱼蛋白胨和苯丙氨酸对淡色库蚊和白纹伊蚊在室内有较好的产卵引诱效果。     

Field and laboratory evaluations of potential oviposition attractants for Aedes albopictus (Diptera: Culicidae)

We tested five volatile synthetic chemicals (dimethyl disulfide, indole, 4-methylphenol, 3-methylindole, and trimethylamine) as potential oviposition attractants of Aedes albopictus in field and laboratory experiments. The 5 synthetic compounds were loaded into controlled-release packets, which consisted of a cellulose material sealed within a permeable plastic membrane, that were used to bait water-filled ovitraps at 5 field sites. Aedes albopictus exhibited no oviposition preference for any of the baited traps versus adjacent traps containing only water. In addition, there was no difference in the mean number of eggs laid per trap-day by Ae. albopictus among ovitraps treated with the five compounds. We conducted behavioral bioassays to determine if the lack of response to the putative oviposition chemicals in the field was due to a concentration effect. A binary sticky-screen bioassay was used to measure attraction of gravid females to olfactory stimuli. Compounds were evaluated over a range of concentrations that spanned 3-5 logs (0.0083 to 8.3 or 83 mg/liter). Three concentrations of 4-methylphenol (0.083 mg/liter, 0.83 mg/liter, and 8.3 mg/liter) and 1 concentration of 3-methylindole (8.3 mg/liter) were significantly repellent. All other concentrations of the 5 chemicals tested did not attract more females than did a water control. Electoantennography indicated that Ae. albopictus did not exhibit a physiological response to 0.25 ng of any of the five chemicals tested. Because Ae. albopictus did not exhibit attraction, greater oviposition. or an electrophysiological response to any of the compounds tested, these compounds do not appear to be effective lures for baiting ovitraps for surveillance or control of this mosquito.     

3种药物对白纹伊蚊的现场控制效果研究

目的观察3种药物在不同使用剂量下对媒介伊蚊成蚊的现场控制效果,为世博期间蚊虫的现场应急处置做好技术储备。方法采用挂笼法观察死亡率,用叮刺法比较成蚊密度下降率(RPI),用诱蚊诱卵器法比较空间喷洒后药物对地面积水中孳生地的影响程度。结果用1∶10和1∶20两种浓度的10%胺-氯菊酯微乳剂处理公园或居民小区,挂笼法死亡率为99%~100%,叮刺法测定对成蚊的控制时间可维持在4~7 d(RPI50以下);对孳生地阳性率也有比较明显的影响,尤其在居民区7 d内的RPI值维持在50;用1∶50和1∶30两种浓度的20%甲基嘧啶磷水乳剂处理公园或居民小区,挂笼法死亡率为86%~96%,叮刺法测定对成蚊的控制时间维持4 d(RPI50以下);对居民区中孳生地阳性率的影响期为7 d,但在公园环境维持时间相对较短。用1∶10和1∶20两种浓度的4.5%高效氯氰菊酯悬浮剂处理居民小区环境后,对成蚊和孳生地控制效果与10%胺-氯菊酯微乳剂相似。结论 3种药物在白纹伊蚊高密度场所用ULV喷洒,4~7 d内均能取得较满意的控制效果。     

宝鸡市白纹伊蚊分布及其种群密度调查

目的了解宝鸡市区白纹伊蚊分布及其密度情况。方法作为中国疾病预防控制中心的白纹伊蚊西北边界调查的合作单位,根据《全国埃及伊蚊、白纹伊蚊分布及其带病毒情况调查方案》,幼虫用孳生地调查法,通过容器指数、房屋指数和布雷图指数计算密度;成蚊调查使用诱蚊诱卵器法、人诱法、帐诱法、诱蚊灯法。结果对市区7类不同生态环境进行蚊虫孳生地及蚊幼虫、成虫密度监测。孳生地共检查各类储水容器642个,阳性率为48.75%,容器指数为52.36,房屋指数为58.12,布雷图指数为71.73;成蚊调查连续3个月(7-9月)共布放诱蚊诱卵器625个,阳性率为12.52%,全部为白纹伊蚊;布蚊帐24帐次,密度为11.17只/人工小时,捕获蚊种以白纹伊蚊为主(76.12%);布放诱蚊灯16个,8、9月蚊虫密度分别为1.09和0.89只/(灯.h),捕获蚊种以淡色库蚊为主,占77.19%,白纹伊蚊占4.35%。结论白纹伊蚊在宝鸡市普遍存在,帐诱、人诱、诱蚊诱卵器调查均显示白纹伊蚊为我市优势蚊种;时间高峰均以8月份为发生最高,密度较高,我们应该重视对该蚊种的控制。     

Field efficacy of four insect repellent products against vector mosquitoes in a tropical environment

Four insect repellent products (RPs) (RP 1, Experimental Repellent Lotion [Bayrepel 12%]; RP 2, Experimental Repellent Cream [Bayrepel 5%]; RP 3, Off! Insect Repellent II Aerosol [deet 15%]; and RP 4, Off! Skintastic II Cream [deet 7.5%]) were evaluated simultaneously for their efficacy against vector and nuisance mosquitoes. The aim of this study was to compare the relative efficacy of RPs based on a new repellent compound, Bayrepel (1-piperidinecarboxylic acid, 2-(2-hydroxyethyl)-1-methylpropylester), with deet (N,N-diethyl-m-toluamide)-based RPs. An 8-h field efficacy of above repellents was evaluated against the day-biting mosquito (Aedes albopictus) and night-biting mosquitoes (Culex quinquefasciatus and Anopheles spp.). Evaluation was carried out by exposing humans with repellent-treated bare limbs to mosquitoes landing and to mosquitoes landing and biting. Repellent product 1 or 2 was applied on the left arm and leg, whereas RP 3 or 4 was applied on the right arm and leg, respectively. Application of these 4 RPs significantly reduced (P < 0.05) the landing and the landing and biting of day-biting and night-biting mosquitoes. All 4 RPs were found to be equally effective (P < 0.05) against Ae. albopictus and Cx. quinquefasciatus. However, for protection against Anopheles spp., RPs 1 and 3 exhibited significantly (P < 0.05) better repellency effect than RPs 2 and 4.     

台州市白纹伊蚊、家蝇、德国小蠊对杀虫剂的抗性调查

目的 掌握台州市白纹伊蚊、家蝇、德国小蠊对几种常用杀虫剂的抗药性现状,为杀虫剂的选择提供参考依据。 方法 采用接触筒法、点滴法、药膜法分别测定白纹伊蚊、家蝇、德国小蠊的抗药性水平。 结果 白纹伊蚊成蚊接触溴氰菊酯、高效氯氰菊酯、氯菊酯、残杀威、马拉硫磷药纸后24 h死亡率均为100%,家蝇对残杀威、敌敌畏、高效氯氰菊酯、溴氰菊酯、氯菊酯的抗性倍数分别为>372.40、5.70、155.21、66.87、10.94倍;德国小蠊对残杀威、敌敌畏、高效氯氰菊酯、溴氰菊酯、乙酰甲胺磷的抗性倍数分别为1.05、0.87、1.30、2.67、1.42。 结论 台州市白纹伊蚊成蚊对测试的5种杀虫剂均敏感,家蝇对5种杀虫剂均产生了抗药性,其中残杀威已失效,德国小蠊对测试的杀虫剂为低度抗性。