假臭草花精油的化学组成及对柑橘木虱的驱避和致死活性

【目的】为了让入侵植物假臭草Praxelis clematidea(Griseb)R.M.KingH.Rob.变废为宝,首次探讨了假臭草花精油对柑橘木虱Diaphorina citri Kuwayama的驱避和致死活性,以用于生物防治。【方法】采用水蒸气蒸馏法提取了假臭草不同部位的精油,并通过气相色谱-质谱联用仪(GC-MS)分析花精油的化学成分,并检测了其对柑橘木虱的生物活性。【结果】假臭草花精油得率(0.31±0.03)%高于茎叶精油的得率(0.23±0.02)%;GC-MS检测显示,假臭草花精油至少含有25种化合物,其中β-荜澄茄油烯(43.85%)和β-石竹烯(30.34%)是其主要成分;花精油浓度为40和50μL·mL~(-1)处理30 min时,对柑橘木虱的驱避反应率均可达到100%。不同浓度的花精油对柑橘木虱具有明显的致死活性。当浓度为50μL·mL~(-1)的时候,浸液法处理九里香Murraya exotica L.嫩梢18 h时,柑橘木虱校正死亡率分别达到(56.25±4.79)%,LC50值为44.83μL·mL~(-1),而熏蒸法48 h时的柑橘木虱校正死亡率仅为(66.33±5.00)%,LC50为24.80μL·mL~(-1)。假臭草花精油对柑橘木虱的驱避和致死活性可能与其主要成分的作用有关。【结论】研究结果证明假臭草花精油对柑橘木虱具有良好的驱避和致死活性,具有开发成为柑橘木虱驱避剂及杀虫剂的良好潜能。     

二化螟盘绒茧蜂及稻虱缨小蜂对挥发物的嗅觉反应

【目的】揭示二化螟盘绒茧蜂Apanteles chilonis Munakata与稻虱缨小蜂Anagrus nilaparvatae对单一水稻挥发物组分的选择行为,了解水稻挥发物在其寄主搜寻过程中的作用,为水稻害虫寄生蜂引诱剂的研发提供技术基础。【方法】利用Y型嗅觉仪测定了二化螟盘绒茧蜂与稻虱缨小蜂对11种水稻挥发物组分(反-2-己烯醛、α-蒎烯、乙酸叶醇酯、芳樟醇、β-石竹烯、反-3-己烯醛、水杨酸甲酯、罗勒烯、苯甲醛、2-壬酮、柠檬烯)的嗅觉行为反应。【结果】β-石竹烯(10、50μg/kg)、罗勒烯(0.1、1、10μg/kg)、2-壬酮(10μg/kg)及反-2-己烯醛(50μg/kg)对二化螟盘绒茧蜂行为具有显著影响;稻虱缨小蜂对反-2-己烯醛(50μg/kg)、反-3-己烯醛(1、10、50μg/kg)、芳樟醇(0.1、1、10μg/kg)、β-石竹烯(0.1、50μg/kg)、罗勒烯(1μg/kg)、α-蒎烯(1μg/kg)和水杨酸甲酯(0.1、1、10、50μg/kg)有显著的嗅觉反应。【结论】寄生蜂对水稻挥发性气味的识别与挥发物的种类和浓度有很大关系,研发水稻害虫寄生蜂的引诱剂时需考虑挥发物的种类与浓度。     

马缨丹叶片水提物与挥发油的生物活性及化学成分研究

研究了马缨丹 ( Lantana camara L.)叶片水提物和挥发油水溶液的化感作用。结果表明 ,马缨丹叶片水溶物浓度在 0 .2 5 g FW m L- 1时 ,对所有受试植物的幼苗生长均有一定的抑制作用 ,浓度降至 0 .1 0 g FWm L- 1时 ,其抑制作用显著降低 ;马缨丹叶片挥发油水溶液在浓度为 1 0 0、2 0 0、30 0 μg m L- 1时 ,对受试植物均有很强的抑制作用 ,且具有明显的浓度效应。采用 GC/MS分析了马缨丹叶片挥发油的化学成分 ,鉴定了 1 9种化感物质 ,其中α-子丁香烯和β-子丁香烯为主要物质 ,分别占挥发油含量的 1 6 .2 9%、2 2 .2 9%。     

生姜精油化学成分及其抗菌活性

【背景】随着耐药微生物种类的增多和耐药性增强,抗耐药微生物新药的发现已成为全球关注的问题。生姜精油是纯天然植物精油,是天然抗菌材料的优选。【目的】分析生姜精油的化学成分,研究生姜精油对常见条件致病菌抗菌活性的影响,并阐明其可能的抗菌机制。【方法】采用气相色谱/质谱技术(Gas Chromatography/Mass Spectrometry,GC/MS)对生姜精油的化学成分进行分析,利用牛津杯法、最小抑菌浓度法(Minimum Inhibitory Concentration,MIC)、最小杀菌浓度法(Minimum Bactericidal Concentration,MBC)和生长曲线绘制法研究生姜精油的抗菌活性和抗菌动力学特征,并通过透射电镜(Transmission Electron Microscopy,TEM)观察生姜精油对细菌超微结构的影响。【结果】生姜精油的化学成分主要为姜烯(22.014%)、β-倍半水芹烯(11.276%)、α-法呢烯(8.222%)、α-姜黄烯(6.854%)、姜酮(5.610%)、姜辣二酮(5.192%)、6-姜烯酚(4.670%)、桧烯(3.393%)和β-红没药烯(3.080%)等萜类物质。生姜精油对枯草芽孢杆菌的MIC和MBC分别为2.3μg/mL和4.6μg/mL;对表皮葡萄球菌及金黄色葡萄球菌的MIC均为9.2μg/mL,MBC均为18.4μg/mL;对肺炎克雷伯菌的MIC和MBC分别为18.4μg/m L和36.8μg/mL。生长曲线结果显示,生姜精油能延长细菌的生长停滞期、抑制细菌的生长速率。透射电镜结果表明,生姜精油能引起细菌细胞膜破损,致使胞内物质渗漏。【结论】生姜精油富含萜类化合物,具有中度的抗菌活性,能破坏细菌细胞膜的完整性,引起菌体损伤和死亡。本文有望更好地为有害微生物的防控提供新方法。     

胡椒木叶片精油成分分析及其抗氧化、驱虫、抗菌活性

为解决在城市绿化中滥用化学农药引起的生态问题,研究了胡椒木(Zanthoxylum piperitum)叶片的精油成分及其驱虫、杀虫、杀菌活性。结果表明,采用石油醚萃取胡椒木叶片精油的最佳工艺条件为提取时间4 h、温度50℃、料液比1:5,得率最高为0.5123%。从胡椒木叶片精油中共鉴定出25个化学成分,主要为酯类、烃类和醇类,占总峰面积的99.96%,而具有驱虫、杀虫和抗菌活性的成分占88.50%,包括肉桂酸甲酯(87.83%)、柠檬烯(0.18%)、薄荷醇(0.11%)、香茅醛(0.10%)、α-蒎烯(0.08%)、α-石竹烯(0.08%)、松油醇(0.04%)、石竹烯(0.03%)、羟基大牻牛儿-1(10),5-二烯(0.03%)和β-水芹烯(0.02%)等。20 mg m L~(–1)的精油对DPPH·自由基的清除率达85.38%,接近BHT阳性对照;但还原性低于Vc,表现出较弱活性,这可能与提取工艺有关。因此,胡椒木叶精油含有多种驱虫、杀虫、抗菌等生物活性成分,具有开发为天然植物农药的潜力。     

华北大黑鳃金龟成虫对三种植物的取食选择及趋性行为反应

【目的】本研究旨在明确华北大黑鳃金龟Holotrichia oblita成虫对3种植物的趋向选择性与取食偏好性的关系及其成因。【方法】利用Y型嗅觉仪和叶面积仪等分别测定华北大黑鳃金龟成虫对榆树Ulmus parvifolia、苘麻Abutilon theophrasti和蓖麻Ricinus communis 3种植物的趋向性和取食量,采用GC-MS分析鉴定这3种植物挥发物的成分,观测其对主要成分的嗅觉反应。【结果】华北大黑鳃金龟成虫对蓖麻的趋向性显著强于对苘麻和榆树的趋向性(P0.05),对苘麻和榆树的趋向程度相当;但对榆树叶片的取食量最大(P0.05),对苘麻和蓖麻叶片的取食量相近,雌虫与雄虫的取食量没有显著差异(P0.05)。通过GC-MS分析鉴定发现,3种植物挥发物主要成分有明显差异。嗅觉反应结果显示,在10μg/μL浓度下,顺-3-己烯基异丁酸酯、邻苯二甲酸二丁酯、顺-3-己烯基乙酸酯、芳樟醇、苯酚、水杨酸甲酯和β-石竹烯等化合物对华北大黑鳃金龟的吸引力都显著强于对照(正己烷);但3-蒈烯、反-2-壬烯醛和α-水芹烯对华北大黑鳃金龟的吸引力弱于对照,并呈显著差异(P0.05)。【结论】华北大黑鳃金龟成虫对榆树、苘麻和蓖麻的趋向选择性不等同于取食偏好性。     

江西迷迭香精油的成分分析及抗氧化、抑菌活性研究

为了研究江西迷迭香精油的化学成分及抗氧化、抑菌活性,采用水蒸气蒸馏法提取迷迭香精油,利用气相色谱-质谱联用法(GC-MS)对迷迭香精油成分进行分析,通过对DPPH自由基、羟基自由基的清除活性和还原力来研究迷迭香精油的体外抗氧化活性;通过以枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌为供试菌,测定抑菌圈大小和最低抑菌浓度(MIC)来研究迷迭香精油的抑菌活性。实验结果表明,从迷迭香精油中鉴定出40种化学成分,占精油总量的99.46%,其主要化学成分有α-蒎烯(39.05%)和1,8-桉叶素(16.86%),其次是莰烯(4.22%)、D-柠檬烯(3.87%)、龙脑(3.74%)、β-石竹烯(3.11%)等,α-蒎烯的含量高于国内其他产地;迷迭香精油对DPPH、羟基自由基和还原力的半数清除率IC₅₀值分别为76.42、51.40和49.15μL/mL;精油对枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌的抑菌圈大小分别为14.40±0.66、11.41±0.19、11.70±0.27 mm,最低抑菌浓度(MIC)分别为2.50、10.00、10.00μL/mL,对枯草芽孢杆菌的抑制作用明显强于金黄色葡萄球菌和大肠杆菌。结果表明迷迭香精油具有较好的抗氧化、抑菌活性。     

印度藏茴香植物精油对温室棉蚜的熏蒸毒性及其成分分析（英文）

【目的】棉蚜Aphis gossypii是世界各地室内和室外果树、蔬菜和观赏植物上最具危害性的害虫之一。这一害虫取食植物汁液,产生蜜露,传播植物病毒,对植物从质和量上产生破坏。为了控制温室中的这一害虫,植物精油可用作化学农药的替代药物。本实验研究了印度藏茴香Carum copticum植物精油对棉蚜成虫的熏蒸毒性。【方法】将研磨的印度藏茴香干种子用改良的挥发油提取器(Clevenger-type apparatus)进行水蒸馏。所有生物测定均在27±2℃,相对湿度65%±5%和光周期16L∶8D条件下进行。研究采用完全随机设计,6个处理(5个不同浓度的精油加对照)。每一浓度3次重复,每一重复20头成虫。【结果】结果表明,棉蚜成蚜接触印度藏茴香精油24 h后出现明显的死亡。该精油对棉蚜成蚜的致死中浓度(LC50)为1.21μL/L空气。棉蚜成蚜的死亡百分率对精油的施用表现出较高的敏感性。精油浓度为1.21μL/L空气时,估计的棉蚜的致死中时(LT50)为11.79 h。这一精油的熏蒸毒性与浓度和接触时间之间具有一定的相关性。GC/MS组分分析结果表明,该精油由18种化合物组成,最重要的是一些化合物引起了熏蒸毒性,如麝香草酚(占50.07%)、γ-萜品烯(占23.99%)和对异丙基苯甲烷(占22.90%)。【结论】本研究结果表明印度藏茴香植物精油对棉蚜具有较好的杀虫效果。印度藏茴香精油对棉蚜产生较大的影响,由于它具有较高的熏蒸毒性潜力,因此可在温室中用于这一害虫的综合治理。     

资源冷杉与元宝山冷杉针叶精油成分的比较

为比较极小种群野生植物资源冷杉(Abies ziyuanensis)和元宝山冷杉(A. yuanbaoshanensis)针叶精油化学组成成分,该文利用水蒸气蒸馏法提取资源冷杉和元宝山冷杉针叶精油,采用GC-MS分析确定其精油化学物质成分,并基于峰面积归一化法计算各组分相对含量。结果表明:分别从资源冷杉和元宝山冷杉针叶精油中鉴定出化学物质21种和22种,其中15种为两种冷杉共有成分;烯烃类物质是资源冷杉和元宝山冷杉针叶精油中含量最高的组分,占比分别为95.94%和95.02%。两种冷杉共有成分中β-蒎烯、1-石竹烯、莰烯、α-石竹烯和异松油烯具有较大开发利用价值;非共有成分方面,资源冷杉中α-松油醇和α-蒎烯以及元宝山冷杉中α-依兰油烯和叶醇均具有较大开发利用价值。以上结果为开发利用两种冷杉针叶精油提供了理论依据。     

四种植物精油对黑翅土白蚁触杀和驱避作用

为筛选出高效防治黑翅土白蚁的天然植物精油,减少有机合成农药的使用,该文研究了大蒜精油、肉桂油、丁香油和印楝素油四种植物精油对黑翅土白蚁的触杀效果和驱避作用。结果表明:大蒜精油、肉桂油和丁香油的浓度为5和10 mg·m L~(-1)时,处理2 h后,黑翅土白蚁的校正死亡率达100%,而相同浓度的印楝素油和对照处理的黑翅土白蚁校正死亡率低于5%。随着处理时间延长,浓度为1.25和2.5 mg·m L~(-1)的大蒜精油、肉桂油和丁香油处理6 h时,黑翅土白蚁的校正死亡率仍达100%,而此时对应的印楝素油和对照处理的黑翅土白蚁校正死亡率仅为10%,说明大蒜精油、肉桂油和丁香油对黑翅土白蚁具有较强的触杀效果。大蒜精油、丁香油和肉桂油在处理黑翅土白蚁2 h后LC_(50)值(半致死量)分别为1.572、1.05和1.03mg·m L~(-1),说明肉桂油对黑翅土白蚁的毒性相对最大,触杀效果最好。此外,10 mg·m L~(-1)的大蒜精油、肉桂油、丁香油和印楝素油的驱避试验表明,处理4、6、8和12 h后,大蒜精油、肉桂油和丁香油三精油处理区的黑翅土白蚁数均显著低于对照区的,驱避率总体93%,而对应的印楝素油的驱避率总体28.5%,表明大蒜精油、丁香油和肉桂油三种植物精油对黑翅土白蚁均有显著的驱避活性。综上可知,四种植物精油中大蒜精油、肉桂油和丁香油在防治黑翅土白蚁方面应用潜力很好,是开发绿色环保白蚁防治药剂的可选材料。     

Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus

Essential oils extracted from 10 medicinal plants were evaluated for larvicidal, adulticidal, ovicidal, oviposition-deterrent and repellent activities towards three mosquito species; Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The essential oils of Juniperus macropoda and Pimpinella anisum were highly effective as both larvicidal and ovicidal. The essential oil of P. anisum showed toxicity against 4th instar larvae of A. stephensi and A. aegypti with equivalent LD95 values of 115.7 microg/ml, whereas it was 149.7 microg/ml against C. quinquefasciatus larvae. Essential oils of Zingiber officinale and Rosmarinus officinalis were found to be ovicidal and repellent, respectively towards the three mosquito species. The essential oil of Cinnamomum zeylanicum resulted into highest repellent (RD95) values of 49.6, 53.9 and 44.2 mg/mat against A. stephensi, A. aegypti and C. quinquefasciatus, respectively apart from oviposition-deterrent potential.     

Laboratory experiments on factors affecting oviposition site selection in Toxorhynchites amboinensis (Diptera: Culicidae), with a report on the occurrence of egg cannibalism

Laboratory experiments tested the effects of water quality and the presence of conspecific and heterospecific immatures on oviposition by Toxorhynchites amboinensis (Doleschall). The females showed a highly significant preference for oak leaf infusion water over distilled water. When twenty starved third and fourth instar Tx.amboinensis larvae were present in the water, substantially fewer eggs were counted from pots containing these conspecifics, than from controls in which no larvae were present. Numbers of eggs from pots containing starved second instar larvae did not differ significantly from controls. Observations of larval behaviour while oviposition was occurring suggested that egg numbers were reduced in containers because of egg cannibalism with third and fourth instar larvae, and not because the larvae caused a deterrent effect. Subsequent experiments confirming the occurrence of substantial egg cannibalism by third and especially fourth instar larvae are described. As with larvae, the presence of Tx.amboinensis pupae in the water had little effect on oviposition. If placed in the water 24 h prior to test, pupae very slightly enhanced its attractiveness, but if introduced immediately before test there appeared to be a slight deterrent effect. With heterospecific larvae, twenty fourth instar Ae.aegypti larvae introduced into infusion water 24 h before test rendered the water slightly attractive, while water in which Ae.aegypti larvae had been reared for 48 h proved highly repellent.     

Chemical compositions and larvicidal activities of leaf essential oils from two eucalyptus species

In the current study, the mosquito larvicidal activity of leaf essential oils and their constituents from two eucalyptus species (Eucalyptus camaldulensis and Eucalyptus urophylla) against two mosquito species, Aedes aegypti and Aedes albopictus, was investigated. In addition, the chemical compositions of the leaf essential oils were analyzed using gas chromatography-mass spectrometry. Results from the larvicidal tests revealed that essential oil from the leaves of E. camaldulensis had an excellent inhibitory effect against both A. aegypti and A. albopictus larvae. The 12 pure constituents extracted from the two eucalyptus leaf essential oils were also tested individually against two mosquito larvae. Among the six effective constituents, alpha-terpinene exhibits the best larvicidal effect against both A. aegypti and A. albopictus larvae. Results of this study show that the leaf essential oil of E. camaldulensis and its effective constituents might be considered as a potent source for the production of fine natural larvicides.     

Efficacy of Piper (Piperaceae) extracts for control of common home and garden insect pests

Extracts from three species of the plant family Piperaceae, Piper nigrum [L.], Piper guineense [Schum & Thonn, and Piper tuberculatum [Jacq.], were tested for efficacy against insects from five orders. All three species contain isobutyl amides, plant secondary compounds that act as neurotoxins in insects. These materials are considered safe to mammals because Piper spp. were used for centuries for spice and medicinal purposes. When 24-h P. nigrum LC50 values were compared between common insect pests from eastern Canada and the northeastern United States, the most sensitive species in order of increasing lethal concentration were eastern tent caterpillar, Malacosoma americanum (F.) < European pine sawfly larvae, Neodiprion sertifer (Geoffroy) < spindle ermine moth larvae, Yponomeuta cagnagella [Hübner] < viburnum leaf beetle larvae, Pyrrhalta viburni [Paykull] < stripped cucumber beetle adults, Acalymma vittatum (F.) < Colorado potato beetle adults, Leptinotarsa decemlineata (Say) < Japanese beetle adults, Popillia japonica [Newman] < hairy chinch bug, Blissus leucopterus hirtis [Montandon]. The life stage tested was the point at which each species causes the greatest amount of damage to the host plant and the point at which most gardeners would likely choose to treat with a conventional synthetic insecticide. Greenhouse trials revealed that the pepper formulations also had a repellent activity, thus protecting plant leaves from 1) herbivory (lily leaf beetle, Lilioceris lilii [Scopoli], adults and larvae and stripped cucumber beetle adults) and 2) oviposition [European corn borer, Ostrinia nubilalis (Hübner)]. Combinations with other botanical extracts were additive at best in toxicity and repellent trials. Nontarget toxicity to beneficial invertebrates is a possibility because the P. nigrum LC50 for beneficial ladybird beetles was 0.2%. P. nigrum extracts can provide a reasonable level of control against lepidopteran and European pine sawfly larvae and also will work as a short-term repellent and feeding deterrent. It is recommended that the use of Piper extracts be restricted to small-scale spot treatments in residential areas where insect pest outbreaks have occurred.     

Larvicidal and repellent potential of Albizzia amara Boivin and Ocimum basilicum Linn against dengue vector, Aedes aegypti (Insecta:Diptera:Culicidae)

Investigations were made to test the larval toxicity and smoke repellent potential of Albizzia amara and Ocimum basilicum at different concentration (2%, 4%, 6%, 8% and 10%) against the different instar (I, II, III and IV) larvae and pupae of Aedes aegypti. The LC50 values of A. amara and O. basilicum for I instar larvae was 5.412 and 3.734, II instar 6.480 and 4.154, III instar 7.106 and 4.664, IV instar 7.515 and 5.124, respectively. The LC50 and LC90 values of pupae were 6.792%, 5.449% and 16.925%, 15.474%. The smoke toxicity of A. amara was more effective against A. aegypti than the O. basilicum.     

Variations in insecticidal activity and chemical compositions of leaf essential oils from Cryptomeria japonica at different ages

The larvicidal effects of the essential oils extracted from the leaves of Cryptomeria japonica at different ages (58, 42, and 26 years old) against 2 mosquito species, Aedes aegypti and Aedes albopictus, were studied. The analysis of major constituents of these essential oils was also investigated. Results obtained from the larvicidal tests, using essential oil from the leaves of 58-year-old C. japonica was found to be most effective against both A. aegypti and A. albopictus larvae, indicating tree age has significant influence on mosquito larvicidal activity. In addition, the eleven pure constituents from C. japonica leaf essential oil were also tested individually against the two mosquito larvae. Among them, alpha-terpinene, gamma-terpinene, p-cymene, 3-carene, terpinolene, and beta-myrcene shows strong larvicidal effect against the two mosquito larvae. Among these pure constituents, 3-carene exhibits the best larvicidal effect against A. aegypti and terpinolene shows an excellent inhibitory action against A. albopictus larvae. The results of this study show that the leaf essential oil and its effective constituents might be considered as a potent source for the production of fine natural larvicides.     

Larvicidal activity of Tagetes patula essential oil against three mosquito species

Larvicidal activity of Tagetes patula essential oil was tested against the fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefaciatus. Five different concentrations of essential oil were studied and the results were compared with that of synthetic insecticide, malathion. A. aegypti (LC(50) 13.57, LC(90) 37.91) was most susceptible followed by An. stephensi (LC(50) 12.08, LC(90) 57.62) and C. quinquefaciatus (LC(50) 22.33, LC(90) 71.89).     

Larvicidal activity of major essential oils from stems of Allium monanthum Maxim. against Aedes aegypti L

The stems of Allium monanthum were extracted, and the major essential oil composition and larvicidal effects were studied. The analyses were conducted by gas chromatography and mass spectroscopy revealed that the essential oils of A. monanthum stems. The A. monanthum essential oil yield was 4.25%, and gas chromatography and mass spectroscopy analysis revealed that its major constituents were dimethyl trisulfide (23.21%), dimethyl tetrasulfide (11.24%) and methlyl propyl trisulfide (8.21%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 23.14 ppm and an LC(90) value of 36.31 ppm. Also, dimethyl trisulfide (≥95.0%), dimethyl tetrasulfide (≥95.0%) and methlyl propyl trisulfide (≥95.0%) were tested against the F(21) laboratory strain of A. aegypti. Methlyl propyl trisulfide (≥95.0%) has good activity with an LC(50) value of 19.38 ppm. Also, the above indicates that other major compounds may play a more important role in the toxicity of essential oil.     

Larvicidal activity of the essential oil from Lippia sidoides Cham. Against Aedes aegypti linn

The aim of this work was to study the larvicidal activity of Lippia sidoides essential oil against Aedes aegypti larvae. The essential oil and its hydrolate (saturated solution of essential oil in water) were obtained by vapor extraction and their chemical composition determined by GL-chromatography coupled to mass spectroscopy. Bioassays were run with the essential oil, pure and diluted hydrolate and with their main constituents thymol and carvacrol. The results obtained showed that L. sidoides essential oil and its hydrolate have larvicidal action against the mosquito A. aegypti, causing an almost instantaneous mortality. Thymol, an alkylated phenol derivative and one of the major components of L. sidoides essential oil, was identified as the active principle responsible for the larvicidal action, causing 100% larval mortality at the lowest tested concentration of 0.017% (w/v). These results suggest that the essential oil of L. sidoides is promising as larvicide against A. aegypti and could be useful in the search of newer, more selective, and biodegradable larvicidal natural compounds to be used in official combat programs and at home.     

Efficacy and repellency of some essential oils and their blends against larval and adult house flies,Musca domestica L. (Diptera: Muscidae)

House flies are global pests and notoriously difficult to control. Essential oils of vetiver, cinnamon, and lavender and their blends were tested for toxic and repellent effects against larval and adult flies. All of the oils had moderate toxicity for eggs. Mortality of 2^nd instar larvae was 57–78% in dipping assays, 38–100% in contact assays, and 94–100% in treated media. Lavender was less effective (38% mortality) than the others (91–100%) in contact bioassays. Oil blends were not more effective against larvae than individual oils. Vetiver and cinnamon oils were strongly repellent (84 and 78%, respectively) for larvae in treated media. None of the oils were repellent for adult house flies in olfactometer assays, but testing of additional products demonstrated significant repellency for neem oil, p‐menthane‐3,8‐diol (PMD), and vanillin. Contact/fumigant toxicity of vetiver, cinnamon, and lavender oils was 100%, significantly higher than mortality from sunflower oil (67%). Blends of oils were not more effective against adults than the individual oils, but blends diluted with sunflower oil were as effective as the individual oils. Essentials oils of vetiver and cinnamon may have potential for fly management in situations where conventional insecticides cannot be used.