On the Range of Action of Adult Culex pipiens s.l.

Mosquitoes are an interesting topic due to their medical importance, as they play an active role in the transmission of many pathogens and parasites, acting as vectors for various pathologies that are deadly to humans, such as dengue, yellow fever, chikungunya, West Nile virus, encephalitis and malaria, among many others that are less common. In terms of morbidity and mortality caused by vector-borne diseases, mosquitoes are the most dangerous animals for humanity and, although they also play a role in the ecosystem as a food source for other organisms, their importance for public health cannot be overlooked. As highly efficient vectors, they put more than three billion people at risk, mainly in tropical and subtropical regions as well as in Europe, since heat waves and flooding are becoming more frequent and severe, and summers are getting longer and warmer, accelerating mosquito development, biting rates, and the incubation of the pathogens within their bodies. Female mosquitoes bite to acquire proteins for the development of their ovaries and eggs and, in the process, acquire pathogens and/or parasites from one vertebrate host and transmit them to another, usually after a short period of replication. Three of their four life stages are lived in still freshwater, so it is crucial to understand their range of action when they reach adulthood and leave the water, in order to plan and implement local prevention measures. A set of georeferenced abundance data collected in mainland Portugal over seven years was linked to cartographed water bodies in a geographic information system to estimate the distances at which Culex pipiens s.l. had a significant presence, with criteria based on the size of the catches. The result allows for an estimate of the fly range of those mosquitoes, which can be used to focus countermeasures.

淡色库蚊(Culexpipienspallens)与击倒抗性(kdr)相关的钠通道基因突变

本研究采用RT -PCR技术,使用简并引物分别从淡色库蚊(Culexpipienspallens)敏感品系和抗溴氰菊酯品系中扩增出钠通道ⅡS4～ⅡS6区域的基因片段,长度为35 9bp。该基因片段所编码的氨基酸与黑尾果蝇(Drosophilamelanogaster)、家蝇(Muscadomestica)、埃及伊蚊(Aedesaegypti)、冈比亚按蚊(Anophelesgambiae)及德国小蠊(Blattellagermanica)等昆虫相应区域的氨基酸序列具有较高的同源性,其同源性分别为95. 8% ,95. 0 % ,10 0 . 0 % ,98 .3%和95 . 0 %。经序列比对,确认抗溴氰菊酯品系淡色库蚊钠通道基因在10 14位点发生了突变:该位点的碱基“A”突变为“T”,其对应氨基酸由亮氨酸(L)变为苯丙氨酸(F) ,该突变(L10 14F型)在多种昆虫中较为常见。

Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi(Diptera:Culicidae)

Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm^2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.

淡色库蚊（Culex pipiens pallens）抗性酯酶活性聚集度及有机磷抗性发展动态研究

本文报道浙江省不同地市淡色库蚊（Ｃｕｌｅｘｐｉｐｉｅｎｓｐａｌｅｎｓ）种群的抗性酯酶活性聚集度和对有机磷杀虫剂抗性的发展动态。通过生物测定法，敌百虫对各地市幼虫种群的半致死浓度（ＬＣ５０）分别是：宁波０．３５ｐｐｍ，杭州０．４６ｐｐｍ，舟山０．４７ｐｐｍ，温州０．６６ｐｐｍ，嘉兴０．７１ｐｐｍ，金华０．７５ｐｐｍ和台州１．４３ｐｐｍ。根据各地的历年资料综合分析，自七十年代以来，蚊虫幼虫对敌百虫的抗性逐渐下降，至九十年代初降至最低，但近几年又有回升趋势。通过雌蚊抗性酯酶活性测定，不同地市的抗性酯酶活性指标（Ｉ．Ｖ．）平均值分别是：宁波５７８０．７，杭州６４２５．９，舟山７０４５．９，嘉兴７２５９．９，金华８２８３．２，温州９０４６．３和台州１２９０７．９。与九十年代初相比有所增高。根据抗性酯酶活性指标相似性分析，宁波可划为中度抗性区，杭州、舟山和嘉兴为中高度抗性区，金华和温州为高度抗性区，而台州为强度抗性区。

Tagetes erecta Linn.and its mosquitocidal potency against Culex quinquefasciatus

Objective:To investigate mosquitocidal effects of ethanolic extract of(lowers of Tagetes erecta(T.erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fresh flowers of T.erecta were extracted in cold with ethanol(5.0 L) and after concentration,the ethanol extract was fractionated with chloroform and petroleum ether to afford a brownish syrupy suspension of ethanol extract(50.0 g),petroleum ether soluble fraction(18.6 g) and chloroform soluble fraction(23.8 g).The larvicidal effect of ethanol extract and their solvent fractions were determined by the standard procedure of WHO against different instars of Cx.quinquefasciatus.Results:Among the tested samples the chloroform soluble fractions showed the highest toxicity and consequently,the lowest LC_(50) values(14.14 μ g/mL,17.06 μ g/mL.36.88 μ g/mL and 75.48 μ g/mL) for all the instars larvae of Cx.quinquefasciatus.The larvae showed comparative tolerance in the course of increasing age and time.Conclusions:It can be concluded that the flowers of T.erecta are very effective natural larvicide and could be useful against Cx.quinquefasciatus.

淡色库蚊(Culexpipiens pallens)微卫星DNA位点的克隆

本研究利用地高辛标记的寡核苷酸 (GT) 8、(CAC) 5、(GATA) 4为探针 ,通过与基因组文库中的重组质粒DNA进行杂交 ,从 6 86个重组质粒中筛选到 8条淡色库蚊 (Culexpipienspallens)的微卫星 (Microsatellite)DNA序列 ,已在GenBank数据库注册 (Accessionnumber:AY5 732 80 AY5 732 87)

Evaluation of Andrographis paniculata Burm.f.(Family.Acanthaceae) extracts against Culex quinquefasciatus(Say.) and Aedes aegypti(Linn.)(Diptera:Culicidae)

Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata（A.paniculata） against Culex quinquefasciatus（Cx.quinquefasciatus） Say and Aedes aegypti（Ae.aegypti ） L（Diptera:Culicidae）.Methods:Larvicidal efficacy of the crude leaf extracts of A.paniculata with five different solvents like benzene,hexane,ethyl acetate, methanol and chloroform was tested against the early third instar larvae of Cx.quinquefasciatus and Ae.aegypti.The ovicidal activity was determined against two mosquito species to various concentrations ranging from 50-300 ppm under the laboratory conditions.Results:The benzene, hexane,ethyl acetate,methanol and chloroform leaf extract of A.paniculata was found to be more effective against Cx.quinquefasciatus than Ae.aegypti.The LC50 values were 112.19,137.48, 118.67,102.05,91.20 ppm and 119.58,146.34,124.24,110.12,99.54 ppm respectively.Among five tested solvent,methanol and ethyl acetate crude extract was found to be most effective for ovicidal activity against two mosquito species.The extract of methanol and ethyl acetate exerted 100%mortality at 200 ppm against Cx.quinquefasciatus and at 250 ppm against Ae.aegypti. Conclusions:From the results it can be concluded the crude extract of A.paniculata was a potential for controlling Cx.quinquefasciatus and Ae.aegypti mosquitoes.

Lead levels of Culex mosquito larvae inhabiting lead utilizing factory

Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact of effluents from the firms.Methods:Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry(AAS).Results:Cx.quinquefasciatus was the most abundant species followed by Cx.gelidus.The levels of lead were higher in the Cx.quinquefasciatus(1.08-47.47μg/g),than in the wastewaters surface(0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the.criteria for lead determination.Conclusions:The Cx. quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination,to complemente conventional techniques.

Larvicidal activity of Dregea volubilis and Bombax malabaricum leaf extracts against the filarial vector Culex quinquefasciatus

Objective:To analyze the larvicidal activity of two plant leaf powder and leaf-extracts, Dregea volubilis and Bombax malabaricum against Culex quinquefasciatus.Methods:The larvicidal bioassay was done for powdered leaves of Dregea volubilis and Bombax malabaricum individually and their methanol extracts against first-,second-,third- and fourth-instar larval forms of Culex quinquefasciatus.Mortality rate was recorded after 24,48 and 72 h of postexposure. LC50 and LG90 values were calculated at different time intervals for third instar larvae. Results:All the graded concentration（0.1%,0.2%,0.3%,0.4%,0.5%） of powdered leaves showed significant（P 【0.05） larval mortality.The mortality rate was higher in 50 ppm doses of methanolic extracts of both the plants against Culex quinquefaciatus.The corresponding 【C50 values were 56.97 ppm and 48.85 ppm,respectively after 24 h of exposure.There is no mortality of non-target organism such as Chironomous circumdatus,Oreochromis niloticus niloticus and Diplonichus annulatum within 72 h of post exposure to 0.1%,0.2%,0.3%crude powdered leaves and methanolic extracts of both the two individual plants under the laboratory condition.The results of preliminary qualitative phytochemical analysis of both the plants revealed the presence of many bioactive principles such as steroids,tannins,flavonoids,triterpenoids,saponins,etc. that may be responsible for their bio-control potentiality.Conclusions:The results have shown potential and eco-friendly use of both plant extracts against larva of Culex quinquefasciatus for the first time.

淡色库蚊(Culex pipiens pallens)抗性酯酶B_2基因类群的抗性变异分析

淡色库蚊对毒死蜱抗性品系表现为酯酶Ｂ２基因扩增。本文对由酯酶Ｂ２基因扩增所导致的ＯＰ抗性在无杀虫剂压力下的变异性进行了研究。研究结果表明，当抗性种群中混有非酯酶基因扩增个体时，其抗性水平逐渐下降，酯酶扩增的概率逐渐减少，这可能与抗性基因在生物学上的不适应性有关；在均一的抗性酯酶基因种群中，抗性水平始终较稳定，酯酶的活性也一直较高，这表明在均一的抗性酯酶基因种群的遗传中，酯酶等位基因拷贝几乎是不会丢失的。根据研究结果。

Mosquito larvicidal properties of Ficus henghalensis L.(Family:Moraceae) against Culex tritaeniorhynchus Giles and Anopheles subpictus Grassi(Diptera:Culicidae)

Objective:To determine the larvicidal efficacy of different solvent leaf extract of Ficus benghalensis（F.benghalensis） against Culex tritaeniorhynchus（Cx.tritaeniorhynchus） and Anopheles subpictus（An.subpictus）.Methods:Twenty five early third instar larvae of Cx. tritaeniorhynchus and An.subpictus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO 2005.The larval mortality was observed after 24 h of treatment.Results:Among three solvent extracts tested the maximum efficacy was observed in the methanol extract.The LC50 and LC90 values of F.benghalensis against early third instar of Cx. tritaeniorhynchus and An.subpictus were 100.88.159.76 ppm and 56.66.85.84 ppm.respectively. No mortality was observed in controls.The chi-square values were significant at P【0.05 level. Conclusions:From the results it can be concluded the crude extract of F.benghalensis was an excellent potential for controlling Cx.tritaeniorhynchus and Art.subpictus mosquito larvae.

Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus and Culex gelidus

Objective:To investigate the larvicidal activity of synthesized silver nanoparticles（Ag NPs） utilizing aqueous bark extract of Ficus racemosa（F.racemosa） was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus（Cx.quinquefasciatus） and japanese encephalitis vectors,Culex gelidus（Cx.gelidus）.Methods:The synthesized Ag NPs was characterized by UV-vis spectrum,X-ray diffraction（XRD）,Scanning electron microscopy（SEM） and Fourier transform infrared（FTIR）.The larvicidal activities were assessed for 24 h against the larvae of Cx.quinquefasciatus and Cx.gelidus with varying concentrations of aqueous bark extract off.racemosa and synthesized Ag NPs.LC50 and r2 values were calculated.Results:The maximum efficacy was observed in crude aqueous extract of F.racemosa against the larvae of Cx.quinquefasciatus and Cx.gelidus(LC50=67.72 and 63.70 mg/L;r2=0.995 and 0.985) and the synthesized Ag NPs(LC50=12.00 and 11.21 mg/L;r2=0.997 and 0.990).respectively.Synthesized Ag NPs showed the XRD peaks at 2θvalues of 27.61,29.60,35.48,43.48 and 79.68 were identified as （210）,（121）,（220）,（200） and（311） reflections,respectively.The FTIR spectra of Ag NPs exhibited prominent peaks at 3 425,2 878,1 627 and 1 382 in the region 500-3 000 cm-1.The peaks correspond to the presence of a stretching vibration of（NH） C=O group.SEM analysis showed shape in cylindrical,uniform and rod with the average size of 250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract of F.racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesized Ag NPs.

淡色库蚊Culex pipiens pallens的电磁行为学效应

为检测市面上销售的电磁产品的驱 (诱 )蚊效果 ,在室内实验箱中 ,以不同型号的 2号驱蚊灯和 4种诱蚊灯产生的电磁波分别照射淡色库蚊 (Culexpipienspallens) ,观测其行为反应。结果表明淡色库蚊在活动、取食和存活等行为生态学方面均产生厌恶性反应。未照射 (CK)蚊子生长正常、活动性强、取食活跃、存活率高 ;电子仪器照射处理后 ,初期 (1天内 )蚊子活泼、活动量较大、存活率较高 ,前期 (1天～ 3天间 )活动加剧、取食减少而存活率降低 ,一定时期 (3天 )后活动性逐渐降低、取食越来越少、存活率明显下降。驱 (诱 )蚊效果检测表明 ,诱蚊灯的诱杀效果比驱蚊灯的驱逐作用对减少蚊虫的数量更明显 ;同时显示 ,诱蚊灯的灭蚊效果均较好 ,但诱蚊作用不十分理想。

Evaluation of aqueous and ethanol extract of bioactive medicinal plant,Cassia didymobotrya(Fresenius)Irwin & Barneby against immature stages of filarial vector,Culex quinquefasciatus Say(Diptera:Culicidae)

Objective:To evaluate aqueous and ethanol extract of Cassia didymobotrya leaves against immature stages of Culex quinquefasciatus.Methods:The mortality rate of immature mosquitoes was tested in wide and narrow range concentration of the plant extract based on WHO standard protocol.The wide range concentration tested in the present study was 10 000,1 000,100,10 and1 mg/L and narrow range concentration was 50,100,150,200 and 250 mg/L.Results:2nd instar larvae exposed to 100 mg/L and above concentration of ethanol extract showed 100%mortality.Remaining stages such as 3rd,4th and pupa,100%mortality was observed at 1 000 mg/L and above concentration after 24 h exposure period.In aqueous extract all the stages 100%mortality was recorded at 1000 mg/L and above concentration.In narrow range concentration 2nd instar larvae 100%mortality was observed at 150 mg/L and above concentration of ethanol extract.The remaining stages 100%mortality was recorded at 250 mg/L.In aqueous extract all the tested immature stages 100%mortality was observed at 250 mg/L concentration after 24 h exposure period.The results clearly indicate that the rale of mortality was based dose of the plant extract and stage of the mosquitoes.Conclusions:From this study it is confirmed and concluded that Cassia didymobotrya is having active principle which is responsible for controlling Culex quinquefasciatus.The isolation of biouctive molecules and development of simple formulation technique is important for large scale implementation.

Mosquito larvicidal properties of Orthosiphon thymiflorus(Roth)Sleesen.(Family:Labiatae)against mosquito vectors,Anopheles stephensi,Culex quinquefasciatus and Aedes aegypti(Diptera:Culicidae)

Objective:To determine the mosquito larvicidal activities of hexane,chloroform,ethyl acetate, acetone and methanol leaf extract of Orthosiphon thymiflorus（O.thymiflorus） against Anopheles stephensi（An.stephensi）,Culex quinquefasciatus（Cx.quinquefasciatus） and Aedes aegypti （Ae.aegypti）.Methods:The larvicidal activity was assayed against three mosquito species at various concentrations ranging from（50-450 ppm） under the laboratory conditions.The LC50 and LC90value of the O.thymiflorus leaf extract was determined by Probit analysis.Results:The LC50 values of hexane,chloroform,ethyl acetate,acetone and methanol extract of O.thymiflorus third instar larvae of An.stephensi were LC50= 201.39,178.76,158.06,139.22 and 118.74 ppm; Cx.quinquefasciatus were LC50=228.13,209.72.183.35,163.55 and 149.96 ppm and Ae.aegypti were LC50=215.65,197.91,175.05,154.80 and 137.26 ppm,respectively.Maximum larvicidal activity was observed in the methanolic extract followed by acetone,ethyl acetate chloroform and hexane extract.The larval mortality was observed after 24 h exposure.No mortality was observed in control.Conclusions:The present results suggest that the effective plant crude extracts have potential to be used as an ideal eco-friendly approach for the control of mosquito vectors.This study provides the first report on the larvicidal activity of this plant crude solvent extract of against An.stephensi,Cx.quinquefasciatus and Ae.aegypti mosquitoes.

Control of human filarial vector,Culex quinquefasciatus Say 1823(Diptera:Culicidae)through bioactive fraction of Cayratia trifolia leaf

Objective:To investigate the mosquito larvicidal activity of Cayratia trifolia(L.)Domin(Vitaceae:Vitales)(C.trifolia)which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides.Methods:Young and mature leaves of C.trifolia were investigated for larvicidal activity against3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year.The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleumether,benzene,chloroform:methanol(1:1 v/v),acetone,absolute alcohol and distilled water.Dose dependent mortality was recorded against each solvent extract.Determination of LD_(50)and LD_(90)were executed through log-probit analysis using the most bioactive fraction.The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables.Justification of larvicidal activity was established through student's t-test.Costing effects were evaluated on the non-target water fauna under laboratory conditions.Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods.Results:Significant variations in mortality rate were noted with respect to the type of leaves(mature and senescence),concentration of leaf extract and between seasons.The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD_(50)and LD_(90)value of 10.70 mg/L and 27.64 mg/L respectively.No significant mortality was recorded in non-target water population.Chromatographic analyses of the water extract revealed the presence of steroids,triterpene glycosides,essential oil,phenolics and diterpenes as secondary phytochemicals.Conclusions:Water extract of C.trifolia leaf promised as a cost effective and potent larvicidal agent against Culex quinquefasciatus.

Adulticidal, larvicidal, pupicidal and oviposition deterrent activities of essential oil from Zanthoxylum limonella Alston(Rutaceae) against Aedes aegypti(L.) and Culex quinquefasciatus(Say)

Objective: To evaluate adulticidal, larvicidal and oviposition deterrent response of the essential oil from dried Zanthoxylum limonella(Z. limonella) fruit against Aedes aegypti(Ae. aegypti) and Culex quinquefasciatus(Cx. quinquefasciatus).Methods: Z. limonella oil was tested by biological assays at 1%, 5% and 10% concentrations in ethanol. Adulticidal efficacy was tested against the 2–3 day old adult females. Larvicidal activity was tested against immature stage of mosquitoes. Oviposition deterrence of the oil was evaluated on gravid females.Results: The adult mortality was observed after 24 h with the LC50 of 6.0% for Ae.aegypti, and 5.7% for Cx. quinquefasciatus. Larvicidal bioassay was carried out with the 10% Z. limonella oil against immature stages of Ae. aegypti and Cx. quinquefasciatus,which caused 100% mortality after 12 h and 24 h. In the larvicidal experiment,Z. limonella showed effective result at 1%, 5% and 10% concentrations with the values of LT50 Ae. aegypti = 9.78, 5.61, 0.24 h for larvae and LT50= 64.08, 21.23 h for pupae;Cx. quinquefasciatus had LT50= 28.46, 20.25, 1.01 h for larvae and LT50= 67.52, 27.96,4.11 h for pupae, respectively. Oviposition deterrence of the oil was evaluated on gravid females. In the study, 10% Z. limonella showed 100% repellency for Ae. aegypti and99.53% for Cx. quinquefasciatus. Likewise, oviposition activity indexes of these oil concentrations were all negative values ranging from–0.89 to-1.00 for Ae. aegypti and–0.64 to–0.99 for Cx. quinquefasciatus. The oviposition activity indexes values revealed that Z. limonella oil has deterrent effect, and it caused a remarkable negative response resulting in very few eggs.Conclusions: This result indicates that Z. limonella oil can be used as an effective adulticide, larvicide and oviposition deterrent against Ae. aegypti and Cx. quinquefasciatus.

Larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri Gagnep against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus mosquito vectors

Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larvicidal activity was tested according to World Health Organization standard protocol.The third-stage larvae of each mosquito species were exposed to various concentrations of Dracaena loureiri crude extract and six groups of Dracaena loureiri fractionated extracts(RC-DT 009-014).Larval mortality rates were observed after 24 h and48 h of exposure.Then,a computerized probit analysis of the mortality data was performed to determine lethal concentration 50(LC_(50))and lethal concentration 90 values.Results:Anopheles minimus larvae(24-h LC_(50)77.88 mg/L)had the highest susceptibility to crude extract,whereas others(Aedes aegypti,24-h LC_(50)224.73 mg/L;Aedes albopictus,24-h LC_(50)261.75 mg/L;and Culex quinquefasciatus,24-h LC_(50)282.86 mg/L)were significantly less susceptible.The most effective groups of fractionated extracts were RC-DT 012 and RC-DT 013.The mosquito species most susceptible to fractionated extracts was Culex quinquefasciatus,with 24-h LC_(50)values of 0.66 and 0.94 mg/L for RC-DT 012 and RC-DT 013,respectively.Conclusions:The larvicidal activity of fractionated extracts is more effective than that of crude extract against all tested mosquito species.For the most effective alternative larvicide,purification and a phytochemical constituent analysis must be performed.

中国尖音库蚊复合组（Culex pipiens Complex）生物分类学的研究──幼虫形态特征的数值分析

本文报道了１９９０年采自我国２１个不同地区的尖音库蚊复合组四龄幼虫形态分类的数值分析结果，经过多因素相关与回归分析发现，呼吸管指数与纬度、经度之间存在着正相关的关系，而呼吸管１－Ｓ第一对毛分枝数和第二对毛分枝数与纬度、经度之间存在着负相关的关系，并建立了上述分类特征与纬度、经度的多元直线回归方程。另外，综合上述三个分类特征，对典型的尖音库蚊、谈色库蚊和致倦库蚊进行了多元判别和典型变量分析。

致倦库蚊Culex quinquefasciatus自然种群动态与环境条件的关系

在广州地区致倦库蚊Culex quinquefasciatus自然种群每年有2个密度高峰。第一个高峰出现在1月到5月,最高密度在3月到5月中,第二个高峰出现在11月到12月。本文分析了温度、相对湿度、降雨量、大气压等物理环境因素对各虫态数量动态的影响。结果表明,上述各因素对种群动态起综合性影响,但不同因素作用的强度不同,即使是同一因素在不同时期影响的强度也有差异。在1月到4月,各虫态的密度随着温度升高而增加,5月以后,随着温度增加而下降,以1月到6月收集的种群动态的资料与温度进行相关分析,有的年份呈正关,有的年份呈负相关,在7月到12月,种群的密度随温度下降而增加,呈显著负相关。不同季节收集的卵的孵化率无明显差异。降雨量对幼虫、蛹的密度有很明显影响,呈负相关。降雨对成虫数量呈负相关影响,但未达显著水平。降雨对卵块数量影响不明显。成虫的数量与大气压成明显的正相关。