Article

Efficacy of the Botanical Repellents Geraniol, Linalool, and Citronella Against Mosquitoes

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

We determined the degree of personal protection provided by citronella, linalool, and geraniol in the form of commercially available candles or diffusers, both indoors and outdoors. Under the uniform conditions of the experiments, all substances repelled significantly more mosquitoes than the unprotected control. Furthermore, the repellents tested were more active when in the form of a continuous release diffuser than in candle form. All candles were 88 g containing 5% of the active ingredient and all diffusers contained 20 g of 100% active ingredient. Indoors, the repellency rate of citronella candles was only 14% while the repellency rate of citronella diffusers was 68%. The repellency of geraniol candles was 50% while the diffusers provided a repellency rate of 97%. No linalool candles were available for study but linalool diffusers repelled mosquitoes by 93%. Outdoors, citronella diffusers placed 6 m from mosquito traps repelled female mosquitoes by 22%, linalool repelled females by 58%, and geraniol repelled females by 75%. Trap catches were significantly reduced again when diffusers were placed 3 m from the traps. We concluded that geraniol had significantly more repellent activity than citronella or linalool in both indoor and outdoor settings.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... On peut néanmoins envisager les huiles essentielles répulsives suivantes pour un spray aromathérapique : -HE Pelargonium graveolens (Géranium rosat) : géraniol, citronellol, linalol (Tabari et al., 2017 ;Omolo et al., 2004 ;Muller et al, 2009) -HE Cymbopogon winterianus (Citronnelle de java) : citronellal (Lee, 2018), géraniol, citronellol (Sharma et al., 2018 ;Omolo et al., 2004 ;Muller et al, 2009) -HE Eucalyptus citriodora (Eucalyptus citronné) : citronellal, citronellol (Sharma et al., 2018 ;Muller et al, 2009) -37--HV Azadirachta indica (Neem) (Reegan et al., 2014) -L'adjonction de vanilline à hauteur de 5%, connu (Songkro et al, 2002) pour sa propriété augmenter la rémanence des HE à visée répulsives, serait souhaitable pour éviter une application trop fréquente Citronellal (Sharma et al., 2018 ;Hao et al., 2008), géraniol (Omolo et al., 2004 ), linalol (Muller et al, 2009) et citronellol sont des molécules qui ont une odeur acide et piquante qui éloignent les moustiques par leurs actions répulsives. Le géraniol a une action répellente supérieure au citronellal et au linalol (Muller et al, 2009). ...
... On peut néanmoins envisager les huiles essentielles répulsives suivantes pour un spray aromathérapique : -HE Pelargonium graveolens (Géranium rosat) : géraniol, citronellol, linalol (Tabari et al., 2017 ;Omolo et al., 2004 ;Muller et al, 2009) -HE Cymbopogon winterianus (Citronnelle de java) : citronellal (Lee, 2018), géraniol, citronellol (Sharma et al., 2018 ;Omolo et al., 2004 ;Muller et al, 2009) -HE Eucalyptus citriodora (Eucalyptus citronné) : citronellal, citronellol (Sharma et al., 2018 ;Muller et al, 2009) -37--HV Azadirachta indica (Neem) (Reegan et al., 2014) -L'adjonction de vanilline à hauteur de 5%, connu (Songkro et al, 2002) pour sa propriété augmenter la rémanence des HE à visée répulsives, serait souhaitable pour éviter une application trop fréquente Citronellal (Sharma et al., 2018 ;Hao et al., 2008), géraniol (Omolo et al., 2004 ), linalol (Muller et al, 2009) et citronellol sont des molécules qui ont une odeur acide et piquante qui éloignent les moustiques par leurs actions répulsives. Le géraniol a une action répellente supérieure au citronellal et au linalol (Muller et al, 2009). ...
... On peut néanmoins envisager les huiles essentielles répulsives suivantes pour un spray aromathérapique : -HE Pelargonium graveolens (Géranium rosat) : géraniol, citronellol, linalol (Tabari et al., 2017 ;Omolo et al., 2004 ;Muller et al, 2009) -HE Cymbopogon winterianus (Citronnelle de java) : citronellal (Lee, 2018), géraniol, citronellol (Sharma et al., 2018 ;Omolo et al., 2004 ;Muller et al, 2009) -HE Eucalyptus citriodora (Eucalyptus citronné) : citronellal, citronellol (Sharma et al., 2018 ;Muller et al, 2009) -37--HV Azadirachta indica (Neem) (Reegan et al., 2014) -L'adjonction de vanilline à hauteur de 5%, connu (Songkro et al, 2002) pour sa propriété augmenter la rémanence des HE à visée répulsives, serait souhaitable pour éviter une application trop fréquente Citronellal (Sharma et al., 2018 ;Hao et al., 2008), géraniol (Omolo et al., 2004 ), linalol (Muller et al, 2009) et citronellol sont des molécules qui ont une odeur acide et piquante qui éloignent les moustiques par leurs actions répulsives. Le géraniol a une action répellente supérieure au citronellal et au linalol (Muller et al, 2009). ...
Thesis
Full-text available
Abstract This university diploma thesis aims to approach through aromatherapy the possible means of prevention and treatments to protect and support therapies against arboviruses. Our contribution to the study of aromatherapy lies in the originality of our subject, which has only been partially explored to date. Arboviruses, public health problem, is a growing concern of governments around the world. Arboviroses are in the expansion phase and dengue, chikungunya and Zika virus, are three cases that are emblematic of the rise in the incidence of these diseases and their health, economic and social consequences (chapter 1). The subject is not simple because of the complexity of pathogenesis mechanisms and the plasticity of arboviruses (chapter 2). In addition, symptomatic allopathic prevention and treatment are limited. In this context, aromatherapy could, under certain conditions, appear to be a credible alternative, especially in its vector control and prophylactic component; this is what we have endeavoured to study in this paper (chapter 3). We have mobilized more than 170 scientific references published in international academic journals. Nevertheless, it is necessary to be extremely careful when using essential oils for pathologies related to arboviruses. Indeed, the precautionary principle is necessary when gaps in the pathogenesis of arboviruses are evident. In the same way, since the action of essential oils on arboviruses is not always supported by clinical studies, their use should be limited pending further methodological and clinical investigation. Key words: Arboviruses, Dengue, Chikungunya, Zika virus, Aromatherapy Résumé Ce mémoire se propose d’aborder par l’aromathérapie les possibles moyens de prévention et les traitements pour se prémunir et accompagner les thérapies face aux arboviroses. Notre contribution à l’étude de l’aromathérapie se situe notamment dans l’originalité de notre sujet qui n’a été que partiellement exploré à ce jour. Les arboviroses, problème de santé publique, se présentent comme une préoccupation croissante des États dans le monde. Les arboviroses sont en effet en phase d’expansion et la dengue le chikungunya et le virus Zika, sont trois cas emblématiques de la montée en puissance de l’incidence de ces maladies et de leurs conséquences sanitaires, économiques et sociales (chapitre 1). Le sujet n’est pas simple de par la complexité des mécanismes de pathogénèse et de par la plasticité génétique des arbovirus (chapitre 2). De plus, la prévention et les traitements allopathiques symptomatiques sont limités. Dans ce contexte, l’aromathérapie pourrait, sous certaines conditions, apparaître comme une alternative crédible notamment dans sa composante de lutte anti-vectorielle et prophylactique ; c’est ce que nous nous sommes attachés à étudier dans ce mémoire (chapitre 3). Nous avons mobilisé plus de 170 articles scientifiques publiés dans des revues académiques internationales. Néanmoins, il faut être extrêmement prudent quant à l’emploi des huiles essentielles lors des pathologies liées aux arboviroses. En effet, le principe de précaution s’impose dès lors que des lacunes sur la pathogénèse des arbovirus est patente. De la même manière, l’action des huiles essentielles sur les arboviroses n’étant pas toujours étayée par des études cliniques, il convient de limiter leur emploi dans l’attente d’approfondissements méthodologiques et cliniques. Mots-clés : Arboviroses, Dengue, Chikungunya, virus Zika, Aromathérapie
... During interactions between pests and host species, the input of the insect olfactory system mediated by host plant-derived volatiles plays a crucial role [40][41][42][43][44][45][46]. These unique compounds were specific in each plant species, which can stimulate the olfactory sense of insects and induce their subsequent preference behavior [42,43]. ...
... These unique compounds were specific in each plant species, which can stimulate the olfactory sense of insects and induce their subsequent preference behavior [42,43]. Due to the characteristics of the rhythmic release of plant volatiles and insect-specific recognition and perception, numerous research studies have now focused on imitating and synthesizing attractants and deterrents for target pests [44][45][46]. ...
... The chemical substance, linalool, has been applied to monitor the oriental fruit fly (Bactrocera dorsalis H.) and Mediterranean fruit fly (Ceratitis capitate W.) attributed to its attractive effects [44,45]; it was also used to manage mosquitoes owing to its repellent function [44,46]. However, the oviposition preference of S. frugiperda female moths dominated by various host volatiles under the wheat-faba bean intercropping system remains unexplored. ...
Article
Full-text available
Spodoptera frugiperda (J. E. Smith), which attacked China in 2019, remains a significant threat to wheat production. Wheat–faba bean intercropping systems prevent damage caused by wheat aphids; however, the potential role in S. frugiperda control remains unclear. Here, the adaptability and preferences of S. frugiperda to wheat and its common intercropped plant, faba bean, were evaluated to implement an eco-friendly approach for S. frugiperda management. Their adaptability showed that both hosts could support S. frugiperda to complete their life cycle; however, the larvae performed worse on faba bean compared with on wheat. The biochemical analysis revealed that faba bean plants had lower contents of soluble sugars and total proteins but higher levels of phenolics and tannins than in wheat leaves. The gravid S. frugiperda preferred (during the preference assays) to oviposit on wheat rather than on faba bean plants in cage tests. The wheat odor was preferred over the faba bean odor in the Y-tube olfactometer bioassays. The morphological scanning electron microscopy (SEM) showed increased trichome density on wheat leaves. Therefore, the faba bean plants displayed antibiosis on larvae and were repellent to female moths, thus, suggesting that faba bean plants could serve as a push crop to be intercropped with wheat for S. frugiperda control for wheat fields.
... Likewise, another way to increase the effectivity of these oils could be to use them synergistically. Müller et al. (2009) have concluded that geraniol has better repellent activity than citronella and linalool, although both linalool and geraniol are constituents of citronella essential oil [51] . Shukla et al. (2018) have used the leaf extracts of lantana, lemongrass, tulsi, calotropis and neem in equal proportion and found that their repellency was enhanced to 5-6 hours from less than 2 hours [33] . ...
... Likewise, another way to increase the effectivity of these oils could be to use them synergistically. Müller et al. (2009) have concluded that geraniol has better repellent activity than citronella and linalool, although both linalool and geraniol are constituents of citronella essential oil [51] . Shukla et al. (2018) have used the leaf extracts of lantana, lemongrass, tulsi, calotropis and neem in equal proportion and found that their repellency was enhanced to 5-6 hours from less than 2 hours [33] . ...
Technical Report
Full-text available
The mosquito vector spread a variety of diseases. It is responsible for several million deaths and hundreds of millions of cases every year and has an adverse effect on public health. There are different types of mosquitoes which bite at different times of the day and spread different viruses. The paper highlights the causes of malaria and their prevention methods in detail. Malaria is a major health problem for children and pregnant women. It has been highlighted as a major cause of death for children below age of five years. More than two-thirds of all malaria deaths occurs in children below age of five years. In India, malaria has been a problem for centuries. India has the highest number of morbidity and mortality rates of malaria after Africa. A number of protective and preventive methods/techniques are adopted against this vector. A common method of preventing mosquito bite(s) is the use of repellents of synthetic and natural origin. The merits and demerits of synthetic and the natural mosquito repellents have been critically assessed. Malaria is preventable and not supposed to be a deadly disease if treatment is available, which is not the case for many of the underdeveloped areas. These regions bear a disproportionate burden of the disease, mainly due to non-adoption of prevention measures. Microencapsulation is one of the techniques to extend the longevity of the repellents used for prevention of mosquito bites. The review briefly assess the various aspects of microencapsulation technique in the mosquito-repellent fabric domain. There is a need for increased research and development of (natural and synthetic) mosquito-repellents.
... Linalool has been reported for insecticidal activity against the insect which affect stored product [61][62][63]75] .It can be used for the control of cat fleas,ticks and fleas [64][65][66] ;mite, T. putrescentiae; fruit files ,Ceratitis capitata and Bactrocera dorsalis [41] ; and housefly ,Musca domestica L. [45] . Linalool has been demonstrated to reduce the presence of female mosquitoes by almost twice as much as citronella candles [46,47] and indoors it repels mosquitoes by 93% [44] . It has been demonstrated to reduce the presence of female mosquitoes by almost twice as much as some ecofriendly insect repellent like Citronella candles [47] . ...
... Most of the Linalool containing plants are used as traditional medicine to cure several types of inflammation [44] .Some experiments also support a possible involvement of linalool to reduce inflammation.Experiments have been done to evaluate the anti-inflammatory properties of (-) linalool,i.e., the naturally occurring enantiomer.The results experimental evidence indicate that linalool play a major role in the anti-inflammatory activity displayed by the essential oils containing them [45,67] . The antiinflammatory effects of linalool in lung cells have been associated with the modulation of pro-inflammatory cytokines and antioxidant enzymes. ...
Chapter
Linalool is an emitted monoterpene compounds of aromatic plants which is commonly found as major component of essential oils.It is one of the important versatile bioactive compound which not only play a pivotal role for the source plant but also utilized by several animals including humans.Since its discovery it has focused an increasing research interest in view of their biochemical features and for probable influence in physiological processes of plants.Till date the existing knowledge regarding Linalool is in stage that needs to be upgraded for successful utilization of it.
... Spatial repellent actives have been incorporated into a wide range of devices, which release the active ingredient either actively by using heat, mechanical aerosolization, or volatilization enhanced by airflow (fan) or passively, through unaltered volatilization and diffusion. reviewed the commercial SR products that have been reported in the literature : impregnated plastic or paper strips, (Yayo et al., 2016) coils, (Avicor et al., 2015;Msangi et al., 2010) candles, (Lindsay et al., 1996;Muller et al., 2008Muller et al., , 2009 fan emanators, (Dame et al., 2014;Lloyd et al., 2013;Revay et al., 2013;Xue et al., 2012a) heat-generating devices, (Collier et al., 2006;Dame et al., 2014;Lloyd et al., 2013), liquid vaporizers, heated mats, and microdispensers . Emanators impregnated with either volatile pyrethroids or essential oils have been reviewed by and also reported, that despite differences in evaluation methodologies, coils, and emanators clearly reduce human mosquito contact . ...
... 293-328. Müller, G.C., Junnila, A., Butler, J., Kravchenko, V.D.,Revay, E.E., Weiss, R.W., Schlein, Y., 2009. Efficacy of the botanical repellents geraniol, linalool, and citronella against mosquitoes. ...
Chapter
The chapter discusses the importance of ticks in public health and the extent of threats posed by tick-borne diseases to the wellbeing of humans. The history of tick control efforts highlights various developments over the years from monitoring tick populations to the development and use of tick repellents and control strategies. Different evaluation techniques and procedures used for spatial and topical arthropod repellents are described and discussed. This chapter also includes and summarizes laboratory bioassays, field methodologies, impregnated and sprayed fabric evaluation methodologies, their efficacy determination, the challenges encountered by the arthropod repellents used, evaluations, and recommendations.
... The ability of essential oils used in these studies to repel other stored product insect pests from commodities has been widely studied e.g., [34][35][36]. Not only are essential oils used to repel insects from food commodities, they are also used for health purposes to prevent malaria [37], since they repel mosquitoes from biting humans [38]. ...
... Past studies confirm that geraniol strongly repels both red flour beetles and booklice in comparison to citronellol and limonene when applied to control these stored product insect pests [15,39]. Another study found that mechanical diffusers with geraniol had a 97% repellent rate compared to other essential oils such as citronella and linalool diffused for repelling mosquitoes [38]. There is substantial information of geraniol having a higher tendency to repel arthropods than other essential oils [40]. ...
Article
Full-text available
The fumigant pesticide methyl bromide (MB) was used for stored products, but it is now banned for most uses in many countries as an ozone-depleting substance. MB was the only pesticide used to manage the ham mite, Tyrophagus putrescentiae, which is the most significant pest of dry cured hams. Effective alternatives to MB are needed to develop integrated pest management (IPM) programs for this pest. This study evaluated plant essential oils and food-safe compounds as repellents to directly protect hams from infestation. Experiments to assess the repellency to orientation, oviposition, and population growth of mites on pieces of aged country hams were conducted. Test compounds at different concentrations were dissolved in respective solvents and compared to the solvent control. Results showed that C8910, a mixture of three short-chain fatty acids, and the sesquiterpene ketone nootkatone had repellency indices of (RI) of 85.6% and 82.3%, respectively, at a concentration of 0.1 mg/cm2, when applied to a Petri dish arena. DEET and icaridin were also tested but performed poorly with RIs below 70% even at 0.1 mg/cm2.The monoterpene alcohol geraniol had the highest RI of 96.3% at 0.04 mg/cm2. Ham pieces dipped in C8910 and nootkatone at 150 ppm each had RIs of 89.3% and 82.8%, respectively. In general, as the concentrations of test compounds increased, the numbers of eggs that were laid on these treated ham cubes decreased after the 48 h exposure time. Ham pieces dipped in different concentrations of test compounds and then inoculated with 20 adult mites showed a significant decrease in mite population growth compared to control pieces after 14 days. The results of these experiments suggest that some plant secondary metabolites and synthetic food-safe compounds could serve as potential alternatives for managing mites on hams.
... Spatial repellent actives have been incorporated into a wide range of devices, which release the active ingredient either actively by using heat, mechanical aerosolization, or volatilization enhanced by airflow (fan) or passively, through unaltered volatilization and diffusion. reviewed the commercial SR products that have been reported in the literature : impregnated plastic or paper strips, (Yayo et al., 2016) coils, (Avicor et al., 2015;Msangi et al., 2010) candles, (Lindsay et al., 1996;Muller et al., 2008Muller et al., , 2009 fan emanators, (Dame et al., 2014;Lloyd et al., 2013;Revay et al., 2013;Xue et al., 2012a) heat-generating devices, (Collier et al., 2006;Dame et al., 2014;Lloyd et al., 2013), liquid vaporizers, heated mats, and microdispensers . Emanators impregnated with either volatile pyrethroids or essential oils have been reviewed by and also reported, that despite differences in evaluation methodologies, coils, and emanators clearly reduce human mosquito contact . ...
... 293-328. Müller, G.C., Junnila, A., Butler, J., Kravchenko, V.D.,Revay, E.E., Weiss, R.W., Schlein, Y., 2009. Efficacy of the botanical repellents geraniol, linalool, and citronella against mosquitoes. ...
Chapter
In this chapter, we describe considerations for the design of experiments to measure the protective efficacy of bite prevention tools against mosquito vectors. The chapter focuses on the evaluation of spatial repellents (specifically volatile pyrethroids) and topical repellents under semifield conditions including a description of the semifield system and experimental huts used to simulate outdoor and indoor use settings, respectively. We also explain the preparation needed for conducting an experiment in these bioassays to maximise data reproducibility as well as the limitations of the experimental systems. Bite prevention technologies are ultimately designed to prevent the transmission of pathogens by inhibiting bites and in some cases killing the vector. We explain the primary outcomes used to measure the efficacy of bite prevention tools, analysis, and data interpretation. We also describe the relationship between data collected in the semifield and the field setting. The chapter ends with a brief description of how these endpoints can be used in mathematical modeling to simulate the expected public health outcome when bite prevention tools are implemented alone or in combination with other vector control tools for the prevention of vector-borne disease.
... The essential oil of the P. hybridus subsp. ochroleucus leaf, which was four times more toxic to Drosophila than the rhizome essential oil was, contained high concentrations of linalool (9.03%) ( Table 1), which is used as a fruit fly and mosquito insecticide [22,23]. Given that the 48 h Plants 2020, 9, 700 9 of 15 LC50 for Drosophila larvae was 0.84% (Table 5), and that additional prolonged toxicity hindered pupae ability to reach imago stadium, essential oil from the leaves of P. hybridus subsp. ...
... Caryophyllene had the PR values of 82% and 98% against T. castaneum after 2 h and 4 h exposure, respectively [22]. These major components were also confirmed to be toxic to other insects, such as Aedes aegypti, Semanstus japonicus and Lasioderma serricorne [42][43][44]. Therefore, this study and the previous reports proved that essential oils from the genus Artemisia have great potential to be developed as good repellent agents against storage insects. ...
Article
As a source of aromatic plants, the genus Artemisia has long been considered to have the potential to develop plant pesticides. In this study, components of essential oils from A. dalai-lamae, A. tangutica, A. sieversiana, A. tanacetifolia and A. ordosica were identified by GC-MS. A total of 56 constituents were analysed, and each species consisted of 9 to 24 constituents. Principle component analysis (PCA) revealed that A. dalai-lamae, A. tangutica and A. tanacetifolia are characterised by monoterpene hydrocarbons and oxygenated monoterpenes. Hierarchical cluster analysis (HCA) showed the most remarkable similarity between A. sieversiana and A. ordosica, but the similarity was still lower than 50%. Contact toxicity and repellency of essential oils were evaluated by bioassays; A. ordosica oil exhibited the most substantial contact toxicity (LD50 = 52.11 μg/cm2) against Liposcelis bostrychophila, while A. tangutica oil showed the most potent contact toxicity (LD50 = 17.42 μg/adult) against Tribolium castaneum. Except for A. dalai-lamae, the other four species showed the same level (p > 0.05) of repellent activity as the positive control against both pests at high concentrations. The results indicated that these five Artemisia species had high chemical diversity and great potential to be developed into more effective and environmentally friendly anti-insect agents.
... The essential oil of the P. hybridus subsp. ochroleucus leaf, which was four times more toxic to Drosophila than the rhizome essential oil was, contained high concentrations of linalool (9.03%) ( Table 1), which is used as a fruit fly and mosquito insecticide [22,23]. Given that the 48 h LC50 for Drosophila larvae was 0.84% (Table 5), and that additional prolonged toxicity hindered pupae ability to reach imago stadium, essential oil from the leaves of P. hybridus subsp. ...
Article
Full-text available
Petasites hybridus (Common butterbur) is extensively used in traditional medicine, and is currently gaining interest and popularity as a food supplement and for its medicinal properties. It contains a large number of active compounds of potential therapeutic activity, but also toxic pyrrolizidine alkaloids. Science-based information is needed to support the developing modern use of this plant, and to direct continued safe practice in traditional medicine. The present study focused on the essential oils from leaves and rhizomes of the understudied P. hybridus ssp. ochroleucus from the Balkans, and evaluated its phytochemistry and potential therapeutic activities (antimicrobial, antioxidant, anti-cholinesterase and anti-inflammatory), as well its toxicology potential (acute toxicity in insects and mice). We studied the essential oils, which are not commonly used in traditional practices, but have a potential for safe use since the toxic pyrrolizidine alkaloids, which are non-volatiles, are usually not present in the distilled essential oils. Pyrrolizidine alkaloids were indeed not detected in the essential oils; ingestion of the essential oils did not induce toxicity signs in mice, and topical application did not elicit skin irritation in humans. The essential oils had no antimicrobial properties against 20 pathogenic bacterial strains, but demonstrated good local anti-inflammatory activity in a Carrageenan-induced paw edema test. An insect toxicity test demonstrated that the leaf essential oil is an efficient insect repellent, and the demonstrated anti-cholinesterase activity suggests a potential for the treatment of neurological conditions. Isopetasin, a sesquiterpene found in plants of the genus Petasites, known to have anti-inflammatory effects, was present only in the rhizomes essential oil (3.9%), and sesquiterpene lactones concentrations were high, likely contributing to the antioxidant activity.
... The volatiles made by Ceratitis fasciventris, Ceratitis anonae, and Ceratitis rosa males also contain linalool and can elicit EAG responses in females (Břízová et al., 2015). In prevention and control strategies, linalool has been used to control B. dorsalis, C. capitata, and M. domestica (Ling Chang et al., 2009;Xie et al., 2019) and has a repellent effect on mosquitoes (Müller et al., 2009). Looking beyond Diptera, the combination of linalool and sex pheromone has a synergistic effect in Lepidoptera (Ochieng et al., 2002;Yang et al., 2004). ...
Article
Insect sensing of odorants plays important roles in various behaviors, including host location, mate attraction, and oviposition site selection. The odorant receptor (OR) is a key protein in insect environmental odor recognition. Most Diptera studies of ORs have focused on Drosophila and mosquitos, so there little known about ORs in the agricultural pest insects Tephritidae. To understand the olfactory recognition mechanism of Bactrocera minax, we sequenced and analyzed 12 B. minax transcriptomes to identify a total of 59 OR genes. Semi-quantitative reverse transcription PCR (RT-PCR) showed that several BminORs were highly expressed in antennae. Available with a complete open reading frame and expressed in the antennae of both sexes at a higher level than those of other BminORs, BminOR24 was selected for further functional analyses. BminOR24/BminOrco expressed in Xenopus oocytes responded significantly to linalool. The identification of B. minax OR genes lays a foundation for further functional studies of OR genes, and functional characterization of BminOR24 provides insight for improving methods for controlling B. minax, a devastating pest insects.
... Another monoterpene alcohol with great potential arthropod-repellent activity is geraniol (Müller et al., 2009). Geraniol was identified in negligible amounts in the essential oil of the selections CN3 and CL2 (Table 2), which were not considered for statistical analysis. ...
Article
The chemical profiles of essential oil-bearing plants can greatly vary as a response to ecological and seasonal changes. For specialty crops such as catnip(Nepeta cataria L.) and lemon catnip, (Nepeta cataria L. var. citriodora), optimizing these conditions based on field performance evaluations and chemical analyses of aromatic profiles can provide a benchmark for future harvest timelines. In this study, we describe the field performance of five lemon-scented N. cataria selections and one commercial lemon catnip line, based on biomass, essential oil yield and essential oil composition, while determining the effects of harvesting time on plant performance and chemical composition. The essential oil was extracted via hydro-distillation and analyzed via gas chromatography–mass spectrometry (GC-MS). The four compounds in highest concentration present in the assessed genotypes were citronellol, geraniol, (E)-caryophyllene and caryophyllene oxide. Biomass, essential oil yield and chemical composition were significantly affected by harvesting times in all genotypes. Essential oils from catnip and lemon catnip cultivars have been used commercially as a source of natural insect repellents. Understanding how ecological and genetic factors affect the secondary metabolism of these crops is a fundamental step for product standardization and commercialization.
... This information could be of great importance to identify naturally provided sources of these compounds. Indeed, the three molecules previously quoted as examples have all been targeted as presenting positive attributes, i.e., geraniol could have applications in insect repellency and for anti-tumor treatments [51][52][53][54], limonene has significative antinociceptive effects [55] and piperitenone oxide is investigated for insecticidal uses and cardiovascular protection [56][57][58]. However, research gaps are still present, since each component has not yet been studied (e.g., beta-copaene, isoabienol), and some kinds of properties are still to be investigated for all the components (e.g., antiviral, immuno-stimulant, cardiovascular protection). ...
Article
Full-text available
Research Highlights: This is the first review of existing knowledge on the Lamiaceae taxa of Greece, considering their distribution patterns and their linkage to the ecosystem services they may provide. Background and Objectives: While nature-based solutions are sought in many fields, the Lamiaceae family is well-known as an important ecosystem services provider. In Greece, this family counts 111 endemic taxa and the aim of the present study is to summarize their known occurrences, properties and chemical composition and analyze the correlations between these characteristics. Materials and Methods: After reviewing all available literature on the studied taxa, statistical and GIS spatial analyses were conducted. Results: The known properties of the endemic Lamiaceae taxa refer mostly to medicinal and antimicrobial ones, but also concern nutritional and environmental aspects. Essential oils compositions with high concentrations in molecules of interest (e.g., carvacrol, caryphyllene oxide, etc.) have been found in some taxa, suggesting unexploited applications for these taxa. Distribution patterns show a higher concentration of endemic Lamiaceae on the island of Kriti and southern Peloponnisos; patterns of the endemics’ properties are also highlighted in the biodiversity hotspot of Kriti. However, the lack of data for two thirds of the taxa, regarding their properties or specific distribution, shows a gap of knowledge. Results on endemic Lamiaceae properties and composition are correlated with the supply or potential supply of ecosystem services and the relevant hotspots have been identified. Conclusions: The Greek endemic Lamiaceae taxa are proved to be of great importance, regarding their chemical composition and the properties they confer. The distribution analysis suggests the existence of clustering patterns of plant species with common properties. Finally, this study highlights knowledge gaps that should be filled in order to ensure the conservation of the endemic Lamiaceae taxa and the preservation of the ecosystem services they provide or could potentially provide.
... Se ha reportado una repelencia espacial de 91.7% contra Culex pipiens en pruebas donde se aplicó linalol en el antebrazo de voluntarios, mientras que se han reportado tasas de repelencia de 58-93% para diferentes especies de mosquitos en pruebas realizadas en interiores y exteriores de casas. 18, 19 En el presente estudio el linalol al 0.1% impregnado en algodón produjo 70% de repelencia espacial, el cual entra dentro del rango reportado por este último. Por su parte, la transflutrina es un piretroide menos polar y más volátil que los piretroides convencionales, por lo que se disemina dentro de un área determinada sin la necesidad de una fuente externa de energía. ...
Article
Full-text available
Objetivo: Evaluar el efecto de repelencia espacial contra Ae. aegypti de dos compuestos químicos impregnados en diferentes tipos de telas. Material y métodos: El estudio se realizó en el periodo 2015-2016 en el Centro Regional de Investigación en Salud Pública, del Instituto Nacional de Salud Pública. Se utilizó el Sistema de Procesamiento de Alto-rendimiento para evaluar la respuesta de Ae. aegypti a transflutrina y linalol, impregnados individualmente a diferentes concentraciones en popelina, algodón y poliéster. También se determinó el efecto de sus mezclas, lavado sobre la residualidad y porcentaje de protección. Resultados: La mayor respuesta de repelencia espacial fue para el tratamiento linalol-algodón al 0.1% (RE= 70 ± 5.77%). La mezcla de linalol 0.1% y transflutrina 0.001% presentó un porcentaje de repelencia espacial similar para los tres tipos de tela. El tratamiento transflutrina-popelina 0.001% mantuvo una residualidad de cinco días. El linalol al 0.1% produjo 62.50% de protección en presencia de un estímulo de atracción. Conclusión: Se sugiere la impregnación de linalol al 0.1% en ropa como medida de protección de las picaduras de Ae. aegypti.
... showed high repellency against the females of Ae. aegypti [55]. ...
Article
Objective: To investigate the efficacies of 12 essential oil (EO) formulations from three Zingiberaceae plants (Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augmenting Eucalyptus globulus (E. globulus) EO against females of Aedes albopictus (Ae. albopictus) and Anopheles minimus (An. minimus). Methods: These formulations were evaluated for their ovicidal, oviposition deterrent and adulticidal activities against Ae. albopictus and An. minimus by a topical method, a double-choice method and a WHO susceptibility test, respectively. Results: It was found that all formulations of Zingiberaceae plants EOs augmented with E. globulus EO were more effective in oviposition deterrent, ovicidal, and adulticidal activities against the two mosquito species than all of the formulations used without E. globulus EO. Their oviposition deterrent, ovicidal and adulticidal activities were equivalent to those of 10% w/v cypermethrin. In contrast, 70% v/v ethyl alcohol as a control alone was not effective at all. The highest synergistic effect in effective repellency against Ae. albopictus was achieved by 5% Alpinia galanga EO + 5% E. globulus EO and against An. minimus was 5% Zingiber cassumunar EO + 5% E. globulus EO. Moreover, the highest synergistic effects in ovicidal activities against Ae. albopictus and An. minimus were achieved by 10% Zingiber cassumunar EO + 10% E. globulus EO and 5% Curcuma zedoaria EO + 5% E. globulus EO, respectively. For the adulticidal activities, the highest synergistic effect against two mosquitoes was achieved by 5% Curcuma zedoaria EO + 5% E. globulus EO. Conclusions: These results suggest that Zingiberaceae plant EOs augmented with E. globulus EO have a high potential to be developed into oviposition deterrent, ovicidal, and adulticidal agents for controlling populations of Ae. albopictus and An. minimus.
... In addition to its great contribution to tea flavor, geraniol is also reported to be a defensive secondary metabolite in plant [49][50][51]. It has been demonstrated to be effective in repelling insects and apparently possessed insecticide properties [52,53]. Geraniol also showed well antipathogenic activity to both plant and insect pathogens [50,51]. ...
Article
Full-text available
When insects attack plants, insect-derived elicitors and mechanical damage induce the formation and emission of plant volatiles that have important ecological functions and flavor properties. These events have mainly been studied in model plants, rather than crop plants. Our study showed that tea green leafhopper (Empoasca (Matsumurasca) onukii Matsuda), a major pest infesting tea attack significantly induced the emission of geraniol from tea leaves, but did not affect the crude enzyme activity of geraniol synthase in tea leaves. An enzyme extract of E. (M.) onukii specifically produced geraniol from geraniol diphosphate. Furthermore, a terpene synthase (EoTPS) was isolated from E. (M.) onukii. This terpene synthase was able to convert geraniol diphosphate to geraniol in vitro. In addition, geraniol had in vitro ability to inhibit the growth of Acinetobacter johnsonii that is endobacterial isolated from E. (M.) onukii. This information illustrates that elicitors from piercing-sucking insects can induce the formation of volatiles from crop plants and advances our understanding of the roles of plant volatiles in the interaction among crops-insects-microorganisms.
... Limonene and linalool, contained in the present EO, were also reported as repellent monoterpenes (Müller et al., 2009;Tavares et al., 2018). Sesquiterpenes, such as elemol, 10-epi-γ-eudesmol, and especially β-caryophyllene as well as caryophyllene oxide, which were present in the EO and almost in all its fractions at significant levels, are endowed with a good repellent activity (Paluch et al., 2009a, b;Ashitani et al., 2015;Cao et al., 2018). ...
Article
For several years, plant derived substances, in particular essential oils, have been the subject of increasing attention in their safe and ecofriendly application to crops, as a powerful alternative to chemical insecticides. For this reason, the essential oil isolated from flowers of Ferula tunetana, a Tunisian endemic plant, was investigated for the first time for its chemical profile, and its toxicity and repellency effects against Tribolium castaneum (Herbst) adults. The analysis by gas chromatography coupled with mass spectrometry (GC/MS) led to determine 92.8–99.1% of the total oil (FEO) and its fractions (F1-F12) obtained every 15 min during the hydrodistillation process. The chemical analysis allowedto identify 77 compounds. α-Pinene (14.3%), a monoterpene hydrocarbon, was the major compound of the raw essential oil. Relatively high amounts of oxygenated sesquiterpenes (44.9–76.8%) were detected, consisting mainly of epi-α-muurolol (3.6–9.5%), himachalol (6.8%) and β-chenopodiol (5.1–7.1%). Regarding the repellency assay, results demonstrated that flowers essential oil of F. tunetana and its fractions displayed interesting repellent property (93%). The median lethal dose (LD50) of the topical application of the oil was 10.44%. Fumigation with the raw essential oil gave a LD50 of 161.89 μL/L air. The overall data suggest that the F. tunetana essential oil might be used to protect stored products from pest attacks, but further studies are needed in order to better understand the synergistic relationship between the phytochemicals contained in the essential oil.
... albopictus the best percentages of spatial repellency were concentrations of 1% and 10%. These results were similar to those obtained by Müller et al (2009), where a repellency of 58-93% was obtained for mosquitoes of the genus Aedes spp and Culex spp. This demonstrates the ability of a repellent of natural origin, such as linalool, to repel different species of mosquitoes. ...
Article
Full-text available
In the present study, the effects of two spatial repellents (SR) were determined for Aedes aegypti and Ae albopictus, the main vectors of dengue, Chikungunya, and Zika fever. The modular high‐throughput screening system (HITSS) was used to evaluate the response of both species to transfluthrin and linalool SR at different concentrations. The highest spatial repellency results for Ae. aegypti were obtained by transfluthrin to 0.001% with 37.50 ± 4.33%, and for linalool to 10% with 77.50 ± 3.90%. For Ae. albopictus, the highest spatial repellency percentages for transfluthrin 0.01% were 45.00 ± 3.78%, and linalool at 1% and 10% were 56.25 ± 7.06% and 56.25 ± 6.46%, respectively. Transfluthrin caused high levels of mortality with 71.25 ± 6.66%, 79.75 ± 8.65%, and 100% to Ae. aegypti and 70.00 ± 5.98% and 98.75 ± 0.82% to Aedes albopcitus. With the results of this study, we concluded that both the transfluthrin and linalool could be used as protection measures against the bite of Ae. aegypti and Ae. albopictus in the integral strategies for the control of vectors in Mexico.
... A monoterpenoid alcohol, Geraniol is a component of many essential oils and commonly used in perfumes and 'botanical' mosquito repellents. Geraniol, dispensed directly into the air or with a candle, effectively protected human test subjects from Ae. aegypti and sand flies in an indoor cage test setup in Puerto Rico (Müller et al. 2008, Müller et al. 2009). In their groundbreaking study from 1925, Bunker and Hirschfelder (1925) ranked geraniol as the least effective of 20 different active ingredients with repellent effects on mosquitoes. ...
Article
Full-text available
Mosquitoes of the Aedes genus are vectors for dengue, chikungunya, Zika, and yellow fever viruses. Mosquito repellents are an effective way to prevent mosquito bites and reduce the spread of mosquito-borne diseases. In the early 90s, the U.S. Environmental Protection Agency (EPA) published a list of active ingredients that pose minimum risk to human health that can be used as pesticides or repellents without passing the EPA registration process. The present study examined the efficacy of 21 of the active ingredients listed by the EPA 25 (B) exempt list and five commercially available sprays that only contained active ingredients from the EPA 25(B) list in repelling female Aedes aegypti (L.) females. We performed choice bioassays in a controlled laboratory environment, using a Y-tube olfactometer to determine attraction rates of humans to female Ae. aegypti in the presence of one of the 21 active ingredients and five commercially available repellent sprays. We found that cinnamon oil, peppermint oil, spearmint oil, lemongrass oil, and garlic oil reduced mosquito attraction to human odor. Of the five commercial repellent sprays, only one reduced mosquito attraction for up to 30 min in our assay. The EPA 25 (B) list contains active ingredients that under the conditions of our assay repel Ae. aegypti.
... Previous studies confirmed that PEA is safe for human consumption at low concentrations (Scognamiglio et al. 2012) and does not cause skin rush or development of toxic hazard for humans (Politano et al. 2013a, b). Geraniol, a naturally occurring terpenoid, has shown to be an effective plant-based mosquito and tick repellent (Tabanca et al. 2013;Müller et al. 2009), insecticide for controlling pests with low mammalian toxicity and biodegradability (Chen and Viljoen 2010). ...
Article
Full-text available
The spread of blacklegged ticks (Ixodes scapularis) and growing threat of Lyme disease transmission has increased demand for effective, safe and environmentally friendly repellent products. Plant-derived essential oils are natural products that exhibit insecticidal and repellant activities and represent a promising alternative to synthetic repellants. However, mechanisms by which ticks detect odor stimuli and how such stimuli may function as repellents are not well understood. We examined the repellent activity of selected essential oil components towards I. scapularis in short- and long-term dose–response trials. To determine the specific olfactory organs involved in detection of chemical stimuli, we tested tick behavioral response in repellency bioassays after removing appendages that house chemosensory sensilla (e.g., foretarsi or pedipalps). New prototype formulae were tested in longevity trials repelling up to 95% of tested ticks after 1 h post-application. This study provides new insight regarding tick olfaction and behavior, and innovative methods for selecting appropriate chemicals for development of novel plant-based repellent products for protection from ticks.
... Ainsi, l'huile essentielle résiduelle de ces tourteaux pourra être extraite par hydrodistillation (A15 ; Uitterhaegen, 2018). En raison de son parfum frais et fleuri s'expliquant par sa teneur élevée en linalool (jusqu'à 77%), elle pourra être utilisée dans l'industrie cosmétique pour la fabrication de parfums, de shampooings ou de savons voire même de détergents ménagers (Lapczynski et al., 2008), ou comme répulsif contre les moustiques (Müller et al., 2009). Néanmoins, en raison de la faible quantité d'huile essentielle présente dans les tourteaux de coriandre, il pourra aussi être plus judicieux de la laisser dans d'autres produits finis tels que des agromatériaux, leur fournissant ainsi une valeur ajoutée. ...
Research Proposal
Full-text available
This is an author's version published in: http://oatao.univ-toulouse.fr/25201
... Chang et al. [83] concluded that three turmerones (artumerone and α+β tumerone) can be extracted optimally at 46.85 • C and 26 MPa to obtain a 71 wt.% yield. Another essential oil well-known for its insect repellent ability is citronella oil due to the presence of main components that consist of citronella, geranial, and limonene compounds [84,85]. Silva et al. [86] used SCO 2 to extract the citronella oil from Cymbopogon nardus (citronella) at 80 • C and 18 MPa to obtain a 2.2% yield. ...
Article
Full-text available
The inception of sustainable and cleaner extraction technology has paved the way for the innovative development of nonconventional extractions, such as supercritical fluid extraction, apart from conventional extraction counterparts. The concept of biomass waste-to-wealth for the conversion of biomass waste or by-products into value-added products for diversified applications had piqued the prominent interest of researchers and industry players, especially with the abundance of biomass resources readily available in tropical regions that have yet to be tapped into to reach their full potential. In this paper, a critical review of the developments of supercritical fluid technology from its initial inception up to commercialized scalability, including its limitations, extraction of potential tropical biomass wastes for various types of applications, such as biopesticides, bio-repellents, phenolics, and lipids for biofuel, and its role in circular bioeconomy and sustainable development approaches, are discussed in detail.
... These results are in agreement with this study that analyzed high content of neral and geranial. Although the repellency of geranial, neral, and linalool or plant essential oils against mosquitoes has been known (Leal and Uchida, 1998;Müller et al., 2009), their rapid evaporation is the most important factor in the loss of efficacy and some essential oils including lemongrass oil may cause skin irritation (Zhang et al., 2012). To prevent the direct contact of repellent oils with human skin and rapid evaporation, the research on the development of a formulation to reduce the rapid loss of plant essential oils into air is needed. ...
Article
Full-text available
Kim D.I., Kim S.-I., Jung J.W., Ilyasov R.A., Jang D., Lee S.-H., Kwon H.W. Spatial releasing properties and mosquito repellency of cellulose-based beads containing essential oils and vanillin. Journal of Asia-Pacific Entomology. 2019. 22(2) : 409-416. DOI: 10.1016/j.aspen.2018.12.024. Abstract. Porous cellulose beads (Viscopearl) manufactured from wood pulp can provide gradual-release action for aromatic substances. Here we immersed lemongrass oil, xanthoxylum oil, and vanillin to apply mosquito repellents. The volatiles from this Viscopearl were analyzed to obtain information for quality control (QC) or specification using a GC–MS, and its standard compounds were determined as linalool, geranial, neral, and vanillin. In a test using a 20 L chamber, it was confirmed that their constant amounts were released continuously and they did not be affected by light. In another monitoring test for 47 days on the Viscopearl equipped with a commercialized air conditioner operated for 8 h every day under indoor conditions, the amounts of all released components increased in proportion to the open number of the pores on the module, which is a housing case containing the Viscopearl. In addition, the concentration of 8 major components including 3 standard QC compounds (linalool, geranial, and neral) in a repellency test room depended on both the ventilation and elapsed time. The vapor from the module did not affect main 7 plastic units of the air conditioner, whereas the Viscopearl equipped with an air conditioner showed good mosquito repellency under test chamber and room conditions that temperature, relative humidity, and carbon dioxide concentration were controlled at 24.8–25.4 °C, 63.8–65.7%, and 708–1383 ppm, respectively. Therefore, the plant essential oil-based repellent Viscopearl has high potential to be used as human protective agent against indoor mosquitoes by applying it to air conditioners.
... W repelentach przeznaczonych do bezpośredniego stosowania na skórę występuje w stężeniu do 6%. Głównym składnikiem czynnym olejku lawendowego jest linalool [13,14]. ...
... In addition to DEET, other repellents of synthetic origin have been applied in commercial formulations, such as picaridin (icaridin, hydroxy-ethyl isobutyl piperidine carboxylate, Figure 2A) and N-acetyl-n-butyl-3-amino propionate (IR3535, Figure 2A). Currently, several natural compounds from essential oils have been also used in commercial repellent formulations due to their satisfactory repellent activity, such as the p-menthane-3, 8-diol (PMD) [18,27] ( Figure 2B) and citronellal ( Figure 2B) [28,29]. Some repellents act as competitive inhibitors of attractant molecules that are exhaled by the mammalian hosts. ...
Article
Full-text available
Repellents are compounds that prevent direct contact between the hosts and the arthropods that are vectors of diseases. Several studies have described the repellent activities of natural compounds obtained from essential oils. In addition, these chemical constituents have been pointed out as alternatives to conventional synthetic repellents due to their interesting residual protection and low toxicity to the environment. However, these compounds have been reported with short shelf life, in part, due to their volatile nature. Nanoencapsulation provides protection, stability, conservation, and controlled release for several compounds. Here, we review the most commonly used polymeric/lipid nanosystems applied in the encapsulation of small organic molecules obtained from essential oils that possess repellent activity, and we also explore the theoretical aspects related to the intermolecular interactions, thermal stability, and controlled release of the nanoencapsulated bioactive compounds.
... This chemotype is reported to be used as a commercial source of citral (neral+geranial) (Kolalite 1998). Some of the predominant compounds in lemon catnip, citronellol and geraniol are also well known arthropod repellents (Müller et al., 2009;Ferreira et al., 2017). ...
Article
Though widely used in the insect repellent, pet toy and essential oil industries, much of the Nepeta genus remains underexplored. A few researchers have made efforts to develop elite genotypes, mainly of the N. cataria species (catnip), with desired traits that are economically relevant in terms of breeding while enhancing or retaining the desired chemical profile of the plant. One of the fundamental aspects for developing improved genotypes is the study of diverse germplasm and, for aromatic plants, those studies also incorporate phytochemical aspects as part of the phenotypical traits. Because plant secondary metabolism is highly sensitive to environmental influence, it is important that comparative studies standardize growing, harvesting, post-harvest and extraction methods in order to avoid unknown influences in chemodiversity studies. Therefore, the present review aims to discuss comparative inter- and intraspecific studies of the Nepeta genus, with focus on terpene metabolites. We start with a brief discussion on the main terpenes produced by plants in the genus and their potential applications and then proceed to discuss literature reports on interspecific comparisons, and intraspecific comparisons among populations, accessions, elite lines and cultivars. The results are discussed in terms of current and potential new uses for Nepeta metabolites and the main avenues for research, including the need to standardize the use of breeding terms.
... Isolation of their components demonstrates that the volatile monoterpenes within them to be primarily responsible for their high bioactivity (Michaelakis et al., 2014;Tisgratog et al., 2016). Of the many monoterpenes screened for repellent properties, geraniol, linalool, citronella, limonene, eucalyptol, and nepetalactone have been identi ed as compounds that are moderately effective at preventing arthropod feeding behavior (Klocke et al., 1987;Gillij et al., 2008;Müller et al., 2009). ...
Chapter
Topical chemical repellents are the most commonly used method of personal protection from arthropod vector species. In mosquitoes, repellents have been shown to be capable of modulating odorant receptors. The manner in which these arthropod repellents can modulate the olfactory system of insects to induce avoidance in the vapor phase appears to be multimodal. The current proposed mode of action of repellents includes activation of an innate neural circuit for avoidance behavior, masking host odor via inhibition of olfactory receptor neurons, and acting as a sensory confusant that scrambles odor coding by changing the normal activation pattern of glomeruli. Recent characterization of the odorant receptor family has identified two additional modes of action: global activation and inhibition through the obligate coreceptor (Orco). Deciphering the mechanisms that lead to behavioral avoidance and identifying inducible targets are necessary steps to develop the next generation of arthropod chemical repellents.
... As a result EOs have been utilized as active ingredients in commercial products. The EOs of citronella (Kongkaew et al., 2011) and tea tree (Ramadass and Thiagarajan, 2015) are used in repellents directly applicable on human skin, for the production of protective garments and nets (Enayati and Hemingway, 2010), as open space repellents in aromatic candles (Müller et al., 2009), and surface cover sprays (WHO, 2006). Surprisingly, the equally documented larvicidal properties of EOs (Evergetis et al., 2012) remain commercially unexploited. ...
Article
Full-text available
Contemporary legislation tends to increase limitation on the use of all synthetic pesticides, promoting bio-pesticides as a safer alternative. Bio-prospecting efforts for bio-pesticides provide results, which rarely reach the industry. Present essay elaborates on our efforts to chart the path from the laboratory bench to field assessment. Eight Mediterranean wild gathered foods provided the essential oils that were assessed as mosquito control agents against the Asian tiger mosquito (Aedes albopictus). Three Lamiaceae essential oils, derived from Satureja thymbra, Origanum onites, and Thymbra spicata presented carvacrol as principal component. All exhibited DEET-like repellent performance and total larvae mortality defining the carvacrol rich essential oil (CREO) as a promising mosquito control agent. A commercial variety of Origanum vulgare ssp. hirtum, was selected as CREO source and subjected to dose-response and eco-toxicity studies. We have found significant larvicidal (LC90 of 58,747 mg/L), and repellent (0.2 μL/cm2) properties, but also severe toxicity (LC90 of 12,806 mg/L) against Macrocyclops albidus. This last figure was the limit for the larvicidal field assessment; while for the repellent evaluation was used double the minimum indication (0.4 μL/cm2). CREO was tested per se as larvicidal agent, and emulsified for both repellent and larvicidal field activity. The emulsified CREO's spatial repellent assessment showed maximum efficacy of 86% in day 1 that gradually declined in the following 2 days (81%, 69%). Both emulsified and crude CREO proved to be efficient larvicidal agents, with crude CREO (3 weeks) overrunning slightly the emulsified (2 weeks) in terms of endurance. Conclusively, CREO in its emulsified form may be considered as a promising mosquito larvicidal and repellent agent, applicable in both precautionary and emergency response measures.
... Interestingly, other studies have reported that linalool is a major compound (>20%) in C. odorata oil and responsible for the commercially sought-after floral smell (Gaydou et al. 1986, Benini et al. 2012, Pavela et al. 2020, while only 2.4% was found in the oil use in the present study. From previous work, using a commercial diffuser containing 20 g of 95.5% linalool effectively protected human volunteers from 93% of potential Ae. aegypti bites when used indoors while also repelling some outdoor mosquito species (e.g., Ae. aegypti, Aedes mediovittatus (Coquillett), Aedes sollicitans (Walker), and Culex nigripalpus Theobald) by 58% from entering a trap placed 6 m distance (Müller et al. 2009). Moore (1934) also found that chemicals derived from esters like terpene (e.g., linalool) strongly stimulated sensilla of Cx. quinquefasciatus compared with nonterpene chemicals. ...
Article
Essential oil of Cananga odorata Hook. F. & Tomson is a source of insect repellent, but contact irritancy and noncontact repellency actions that stimulate insect’s avoidance behavior (escape away from chemical source after direct physical contact or without making physical contact, respectively) have not been investigated. Therefore, an excito-repellency test chamber was used for measuring avoidance behavior of four insectary-reared mosquito species (Diptera: Culicidae) that escape from esposure to four concentrations (0.5, 1.0, 2.5, and 5.0% v/v) of C. odorata oil. The oil strongly repelled both Culex quinquefasciatus Say (85–97% escape) and Anopheles minimus Theobald (97–99%) at high concentrations (2.5–5.0%). For Anopheles dirus Peyton & Harrison and Aedes aegypti (L.), highest repellency (64 and 39% escape, respectively) was demonstrated at 2.5% concentration. For contact irritancy, the oil produced relatively high percent escape found in Cx. quinquefasciatus (90–100% escape) and An. minimus (83–100%). Whereas moderate contact irritancy was observed against An. dirus (40–50% escape) and Ae. aegypti (51–59%). The percent escape was then adjusted with repellency to estimate the effect of contact irritancy alone. We found that highest contact irritancy was presented at 0.5% concentration against An. minimus (67% escape). Knockdown and toxic actions were only found in Anopheles mosquitoes at 5.0% concentration. The results revealed that An. minimus and Cx. quinquefasciatus were more prone to be repelled by C. odorata oil. Detailed analysis of oil identified primary compounds as methyl benzoate (14.6%), α-gurjunene (12.8%), p-methyl-anisole (11.3%), and benzyl acetate (9.9%). Further investigations are needed to assess excito-repellency actions of these compounds alone or in combination.
... In a study lemongrass oil extract added to 25% geraniol oil exhibited longest protection time against mosquitoes 15 . Müller et al. 16 determined the degree of personal protection provided by commercial citronella, linalool and geraniol candles or diffusers. Indoors, the repellency rate of geraniol candles was 50%, while the diffusers provided a repellency rate of 97%. ...
Article
Full-text available
Cymbopogon martinii is a grass from genus Cymbopogon (lemongrasses) native to India, but widely cultivated in other places for its aromatic essential oil. C. martinii known as Palmarosa smells sweet with rose-like odor. Geraniol, a terpene alcohol present in Cymbopogon martinii essential oil (CMEO) is much valued for its typical aroma and medicinal uses. In addition to the pleasant odor, Geraniol is known for fungicidal, nematicidal, acaricidal, insecticidal, repellent properties hence, used as Natural Pest Control Agent (NPCA) exhibiting low toxicity. Furthermore, geraniol has been suggested to exemplify a new class of chemoprevention agents in the treatment of cancer. Biological activities such as antimicrobial, anti-oxidant, anti-inflammatory and vascular effects have been investigated. In the present study, GCMS based in-silico ADMET pharmacoinformatics aspects (Physicochemical, Lipophilicity, Medicinal Chemistry, Druglikeness, Absorption, Water Solubility, Distribution, Metabolism, Pharmacokinetics, Excretion, Environmental Toxicity, Tox21 Pathway and Toxicophore Rules) with PASS prediction of geraniol from CMEO has been bioprospected from human health perspective point of view.
... As a result EOs have been utilized as active ingredients in commercial products. The EOs of citronella (Kongkaew et al., 2011) and tea tree (Ramadass and Thiagarajan, 2015) are used in repellents directly applicable on human skin, for the production of protective garments and nets (Enayati and Hemingway, 2010), as open space repellents in aromatic candles (Müller et al., 2009), and surface cover sprays (WHO, 2006). Surprisingly, the equally documented larvicidal properties of EOs (Evergetis et al., 2012) remain commercially unexploited. ...
... Conversely, we measured a greater amount of linalool in 'Craft' than in 'Hockett,' thus the concentration of this monoterpene may play a role in orienting C. cinctus females away from 'Craft' at close range. This is because linalool is well known as a defense compound in plants by either direct toxicity (Weaver et al. 1991, Davoudi et al. 2011 or repellency (Müller et al. 2009, Dekker et al. 2011) as well as an attractant for natural enemies of pests (Du et al. 1998, Kessler andBaldwin 2001). The release of greater amounts of linalool from wheat and barley plants induced by C. cinctus larval feeding, after pathogen infection or after mechanical injury are well documented (Piesik et al. 2006a(Piesik et al. , 2006b(Piesik et al. , 2009(Piesik et al. , 2011(Piesik et al. , 2013. ...
Article
Wheat stem sawfly, [Cephus cinctus (Hymenoptera: Cephidae)], females display complex behaviors for host selection and oviposition. Susceptible hollow stem wheat (Triticum aestivum L.) cultivars release a greater amount of attractive compound, (Z)-3-hexenyl acetate and receive a greater number of eggs compared to resistant solid stem wheat cultivars. However, barley (Hordeum vulgare L.) is becoming a more common host for C. cinctus in Montana. Therefore, how do host selection and oviposition behaviors on barley cultivars compare to what happens when encountering wheat cultivars? To answer this question, we carried out greenhouse experiments using two barley cultivars: 'Hockett' and 'Craft'. Between these cultivars at Zadoks stages 34 and 49, we compared host selection decisions using a Y-tube olfactometer, compared oviposition behaviors on stems, and counted the number of eggs inside individual stems. In Y-tube bioassays, we found a greater number of C. cinctus females were attracted to the airstream passing over 'Hockett' than 'Craft' barley cultivars. Although the frequencies of oviposition behaviors were similar between these cultivars, the number of eggs was greater in 'Hockett'. Volatile profiles indicated that the amount of linalool was greater in the airstream from 'Craft' than in 'Hockett' at Zadoks 34 while the amount of (Z)-3-hexenyl acetate was greater in airstream from 'Hockett' at both Zadoks 34 and 49. These results suggest that volatiles of barley plants influenced host selection behavior of ovipositing C. cinctus females, while other discriminating behaviors do not differ between cultivars.
... Among them, linalool, myrcene, β-caryophyllene, limonene, geraniol, nerol, β-citronellol, α-pinene, β-pinene, caryophyllene oxide, butyl acetate, hexanal, α-terpineol, and some others were proven to be active toward selected pathogens. [16,163,[169][170][171][172][173][174][175] The positive effects of these constituents emphasize that further research on HEO pesticides is definitely necessary and promises remarkable breakthroughs. ...
Article
Hop cones (Humulus lupulus L.), or more specifically the lupulin glands, hold the reason for the specific, pleasant aroma of hops – its essential oil. The hops themselves, or the extracted oil, are used almost exclusively in beer production. The essential oil is an indispensable part of beer and is responsible for its characteristic aroma. However, hop essential oil (HEO) also has a broad range of positive effects on human health and is a potential natural pesticide that has no harmful impacts on humans. This review summarizes basic information about HEO, including its chemical composition and methods for extraction and analysis, while also providing a comprehensive overview of the contribution to beer aroma, health, and insecticide applications for this versatile essential oil.
... Perennial interspecific hybrid Thymus × citriodorus (parental species T. vulgaris and geraniol chemotype of T. pulegioides) (Stahl-Biskup and Holthuijzen 1995), also is fit for its cultivation in Baltic region. The main compound of essential oil of T. × citriodorus and T. pulegioides geraniol chemotype is geraniol with rose-lemon-like odour; this commercially important acyclic monoterpene alcohol is a fragrance ingredient usable in multiple cosmetic products, and it is characterised by antimicrobial activity against pathogenic microorganisms, by repellent properties (Burt 2004;Chen and Viljoen 2010;Lapczynski et al. 2008;Müller et al. 2009). ...
Article
Essential oils and geraniol-bearing taxa of genus Thymus have potential significance in pharmaceutical and fragrance industries as sources of lemon flavour and fragrance essential and natural origin biologically active compound geraniol. The aim of this study was to estimate effects of meteorological conditions on yield of essential oil and their main compounds in Thymus pulegioides geraniol chemotype and geraniol-bearing interspecific hybrid Thymus × citriodorus cultured in same locality. Hybrid and two individual plants of T. pulegioides were vegetative propagated and grown in the open ground under the same environmental conditions. The volatile oils were isolated by hydrodistillation annually, analysis of main compounds of essential oils—geraniol, nerol, geranial, and neral—was carried out by GC-FID and GC–MS. Observed positive relationship of essential oil yield with rainfall and negative with temperature, sunshine duration and photosynthetically active solar radiation showed that a cool weather, little sunny and moisture are suitable for accumulation of essential oil and geraniol in hybrid T. × citriodorus. Two clones of T. pulegioides geraniol chemotype accumulated the lowest and the highest amounts of volatile oils not in same years. Regression analysis showed unlike trends of effects of many meteorological conditions on yield of essential oil in T. pulegioides samples. Only rainfall and temperature most similarly influenced essential oil accumulation in both T. pulegioides clones. The percentage of geraniol was affected by meteorological conditions more similarly in both T. pulegioides; only effect of rainfall on percentage of geraniol was unlike in different samples. Results showed that same meteorological conditions can differently influence essential oil accumulation not only in different Thymus taxa containing similar chemical composition of essential oils, but also in representatives of same chemotype of same Thymus taxa.
... Few reports have revealed that linalool, an acyclic monoterpene alcohol, could be used as insect-repellent against corn earworm (Helicoverpa armigera), spider mite (Tetranychus urticae), mosquito (Aedes aegypti) and beetles (T. castaneum and Dominica Rhyzopertha) [60][61][62]. But linalool was suggested to function as an attractant at least at the beginning of host plant searching for western flower thrips (Frankliniella occidentalis) [63]. ...
Article
Full-text available
Background: Asian citrus psyllid (ACP) is the primary vector responsible for the transmission of the phloem-limited bacteria Candidatus Liberibacter spp., associated with huanglongbing (HLB), which causes great loss to the citrus industry. Although the roles of leaf color and volatile compounds in the orientation of ACP have been proven, the quantification of color and allelochemicals in the host plant are kept unclear, especially in wild citrus germplasms. Results: Chongyi wild mandarin significantly attracted more ACP than wild Hong Kong kumquat, 'Gannan zao' navel orange and orange jasmine did in the four-choice and olfactometer assays. The color parameters of the tender leaves from Chongyi wild mandarin and 'Gannan zao' were similar. The yellow color in both of them was less saturated than that of the other two plants species, but Chongyi wild mandarin had significant lower carotenoid content (P < 0.05). Notably metabolic profiling differences were observed among the healthy tender shoots from the four tested plants via UPLC-QQQ-MS and GC-MS analyses. Comparing with the other three plant species, 66 and 50 metabolites with significantly different contents in Chongyi wild mandarin were selected as UPLC-identified and GC-identified metabolites of interest (P < 0.05), respectively. Flavonoids accounted for a large group of secondary metabolites of interest, which may function as stimulants or repellents of ACP. Higher content of salicylic acid o-hexoside and lower content of (+)-jasmonic acid in Chongyi wild mandarin may lead to higher amount of methyl salicylate (an ACP attractant) and lower amount of trans-ocimene (an attractant to herbivores' natural enemies) as well as the suppression of JA-mediated wounding response. This kind of synergistic or antagonistic effect among the metabolites differentially accumulated in Chongyi wild mandarin made it a more attractive host plant to ACP. Conclusions: Less saturated yellow color, high amount of attractants, low amount of repellents and insensitivity of JA-mediated wounding response are the four possible reasons why Chongyi wild mandarin attracted more ACP. This work may shed light on the olfactory and visual response of ACP to wild citrus germplasm hosts, and suggest the feasibility of developing ACP attractants or repellents patterned on potential metabolites.
... Among the herbal essential oils that can be used as repellent are Cananga oil (Soonwera, 2015). The main constituents of Cananga oil were caryophyllene , α-linalool, α-caryophyllene, germacrene D, and benzyl benzoate (Pujiarti, R;et.al., 2015), from these various contents, linalool has a distinctive pungent odor that is not favored by insects (Müller et al., 2009). ...
Conference Paper
Full-text available
The constituent of Cananga oil is caryophyllene, linalool, and germacrene D, and the main constituent of patchouli oil is the sesquiterpene patchoulol, all have a repellent effect. Moreover, the patchouli oil has a fixative property. The combination of cananga and patchouli oil expected to give a more durable repellent effect. This study conducted to investigate the characteristics and the effectiveness of repellent lotion that contained cananga and patchouli oil. Made lotions that contained cananga oil 7.5% combined with patchouli oil 1%, 2%, and 3%. The characteristic test consists of organoleptic, homogeneity, emulsion type, viscosity, pH, and stability with the freeze-thaw cycle method. The activity test as a repellent using Aedes aegypti mosquitoes for 150 minutes, each period for 30minutes with 3minute exposure. The repellent lotion all the formula has the same characteristic, they are homogeneous, soft, aromatic textured liquid, an oil-in-water type emulsion, and easily dispersed, they have a good pH and viscosity, remain stable after the freeze-thaw cycle testing. While the result repellent test showed the protective power all formula is not different (Two-way ANOVA; a=0.05), they are effective as a repellent for 60 minutes.
Article
Full-text available
Main conclusion Transgenic tobacco plants overexpressing the monoterpene alcohol geraniol synthase exhibit hypersensitivity to thermal stress, possibly due to suppressed sugar metabolism and transcriptional regulation of genes involved in thermal stress tolerance. Monoterpene alcohols function in plant survival strategies, but they may cause self-toxicity to plants due to their hydrophobic and highly reactive properties. To explore the role of these compounds in plant stress responses, we assessed transgenic tobacco plants overexpressing the monoterpene alcohol geraniol synthase (GES plants). Growth, morphology and photosynthetic efficiency of GES plants were not significantly different from those of control plants (wild-type and GUS-transformed plants). While GES plants’ direct defenses against herbivores or pathogens were similar to those of control plants, their indirect defense (i.e., attracting herbivore enemy Nesidiocoris tenuis) was stronger compared to that of control plants. However, GES plants were susceptible to cold stress and even more susceptible to extreme heat stress (50 °C), as shown by decreased levels of sugar metabolites, invertase activity and its products (Glc and Fru), and leaf starch granules. Moreover, GES plants showed decreased transcription levels of the WRKY33 transcription factor gene and an aquaporin gene (PIP2). The results of this study show that GES plants exhibit enhanced indirect defense ability against herbivores, but conversely, GES plants exhibit hypersensitivity to heat stress due to suppressed sugar metabolism and gene regulation for thermal stress tolerance.
Article
A natural insecticide developed from the mixture of the essential oils (EOs) of Cymbopogon citratus (DC.) Stapf (Poaceae), Cedrus atlantica (Endl.) Manetti ex Carriére (Pinaceae), and Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson (Myrtaceae) was studied. The mixture of oils caused high mortality (LD50 = 0.018 μl/insect) to the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), a globally important pest, after topical application on adults. Based on the chemical characterization of biopesticide using gas chromatography-mass spectrometry (GC-MS) analysis, many of the constituents had known insecticidal properties (the monoterpenes α-citronellal and E-citral and the sesquiterpernes α-himachalene and β-himachalene, all at concentrations above 15%). Phytotoxicity tests on orange trees demonstrated that this natural product was harmless when the mixture was applied diluted in water with a surfactant. The mixture of EOs was also harmless (1, IOBC category) to the biological control agent responsible for reducing populations of tephritids, the parasitoid Psyttalia concolor (Hymenoptera: Braconidae), following exposure to treated orange trees in a semifield assay within a greenhouse, but killed 46.2% of C. capitata (Szépligeti) adults after 72 h. Our results suggest that mixture of EOs has potential for use as an adulticide against medfly, although the production price was exceedingly high compared with that of commercial synthetic insecticides. Therefore, we discuss the advantages and disadvantages related to the potential use of this natural insecticide.
Article
Full-text available
Seven ferns of Pteridaceae, grown in a botanical garden or wild, harvested in France were investigated for their Volatile Organic Compounds (VOC) profile using GC-MS: Adiantum pedatum L., Adiantum peruvianum Klotzsch, Anogramma leptophylla (L.) Link, Cheilanthes maderensis Lowe, Cryptogramma crispa (L.) R. Br., Pteris cretica L. and Pteris vittata L. Fifty-three VOC biosynthesized from lipidic, shikimic, terpenic and carotenoid pathways were identified. The two Adiantum species show different VOC composition. The main linalool (10.8%) in A. pedatum has several biological activities of great interest. This Maidenhair fern contains the highest proportion (57.9%) of isoprenoid flavor precursors, i.e., ionone derivatives with various scent notes. The two major odorant unsaturated hexenoic acids derivatives of A. peruvianum are used as flavouring agents. Anogramma leptophylla concentrates 6-methoxymellein (71.5%), a bitter phytoallexin which contributes to stress or pathogen resistance. Cheilanthes maderensis produces mainly coumarin (89%) and vanillin (3.5%) with a low odor detection threshold, both used in perfumery and cosmetic industry or as flavouring agent and drug additives. Cryptogramma crispa accumulates a broad-spectrum of carotenoid derivatives (52.1%) and three major shikimic derivatives: the spicy 4-vinylguaiacol (flavouring agent), the floral phenylethanal and benzyl alcohol with floral, balsamic scent. Pteris cretica accumulates mostly furan derivatives, i.e., 5-hydroxymethylfurfural (33.2%) and 3-hydroxy-2,3-dihydromaltol (18.3%) used as food and beverage additives with caramel or roasty flavour and also found in fortified wines, toasty or heat-treated foods. Pteris vittata produces predominantly shikimic derivatives applied in perfumery and food industries as benzaldehyde (26%, with almond scent), benzyl alcohol (22%, floral fruity balsamic scent), nonanal (19.8% cucumber note) and phenylethanal (11%; floral note). Pteridaceae resources are of great interest as a reservoir of odorous and bioactive compounds. Keywords: Benzaldehyde, Coumarin derivatives, Furan derivatives, Linalool, 6-Methoxymellein, Nonanal, 4-Vinylguaiacol.
Article
Attractive toxic sugar baits (ATSBs) require target insects to locate, orient toward, and feed on an insecticidal sugar solution to control populations. Formulating these baits with different attractants and phagostimulants can increase their efficacy by causing insects to choose the ATSB over competing natural sugar sources, and to ingest more of the bait solution. We tested formulations of a 20% sodium ascorbate (SA) ATSB solution using different sugars, adenosine triphosphate (ATP), gallic acid, and six plant volatile compounds to determine their effect on adult Aedes aegypti (L.) and Anopheles stephensi Liston mortality. Baits formulated with fructose or sucrose had no effect on either species, neither did the addition of ATP. Gallic acid increased the survival of Ae. aegypti. Four of the six volatile compounds increased mortality in at least one species. We also examined An. stephensi response to baits formulated with each of the six volatile compounds. Anisaldehyde significantly increased the number of mosquitoes responding toward the SA-ATSB, but increasing the amount had no effect. Addition of anisaldehyde also significantly increased An. stephensi feeding rates on the SA-ATSB, though mosquitoes will avoid the toxic bait if a nontoxic sugar source is available. Formulation of SA-ATSBs with synthetic blends of attractive compounds can increase bait efficacy and consistency, though further research is needed to assess their performance in the field in the presence of natural sugar sources.
Article
The inclusion of the linear monoterpene, geraniol (gr) in β-cyclodextrin (β-CD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD) has been studied by X-ray crystallography and Molecular Dynamics simulations. The gr/β-CD complex crystallizes as a head-to-head dimer in the P21 space group stacking along the crystallographic a-axis in a channel packing mode. Two guest molecules are accommodated almost axially inside the dimeric cavity with their aliphatic ends laying in the interface region of the dimer facing each other and their hydroxylic ends protruding from the narrow β-CD rims. The guest molecules of the adjacent dimers in a channel are interconnected via CH ⋯O and hydrogen bonds forming an internal wire. Both the gr/DM-β-CD and gr/TM-β-CD complexes crystallize in the P212121 space group and stack along the crystallographic b-axis in a head-to-tail manner. DM-β-CD host adopts the conformation of a rigid and well-shaped open cone upon complexation, in which the guest molecule is found highly disordered over 5 sites with varying depths of immersion. The gr/DM-β-CD complex units are arranged in channels and the gr molecules within these channels are also interconnected via CH ⋯O bonds. On the other hand, TM-β-CD host is found severely distorted adopting a ‘closed’ cup-shaped conformation. The guest is partially encapsulated in the wide rim of TM-β-CD and it is found disordered over 3 sites with quite different orientations. The complex units are arranged forming screw channels, with the main part of the guest laying outside the host cavity and filling the intermediate space between the succeeding hosts. The MD analysis based on the crystallographically determined structures sheds light on the dynamic behavior of the geraniol upon complexation with these hosts, its conformation variations and the interconversion of the inclusion modes in solution. Finally, MM/GBSA-calculations revealed that the ascending order in binding affinity ΔG values is: gr/TM-β-CD < gr/DM-β-CD < gr/β-CD.
Article
The insecticidal and repellent activities of the floral-derived constituents of Magnolia kobus, i.e., linalool, cinnamyl alcohol and farnesene, were investigated against the Asian tiger mosquito Aedes albopictus (Skuse). The main constituents of M. kobus flowers in the early and full-bloom floral stages were obtained using solid phase microextraction (SPME) and analyzed by gas chromatography–mass spectroscopy (GC–MS). The main compounds were the same at both floral stages, though their content ratios differed significantly. The larvicidal activity of the chemical constituents of the full-bloom floral stage caused higher mortality than did constituents of the early floral stage (48 h LC50 = 20.17 ppm and 36.68 ppm, respectively). Adulticidal activity was determined by a topical application method, but there was no significant difference between the materials. The fumigant activity against adult female Ae. albopictus was high in the early floral stage (48 h LD50 = 0.14 mg/cm³), which appeared to be due to the high linalool content (32.9 %) at this time, and the chemical constituents of this stage showed high repellency. All materials exhibited concentration-dependent activity after 2 h of treatment with N,N-diethyl-meta-toluamide (DEET) as a positive control. In conclusion, application of all M. kobus floral-derived materials described herein either as a mixture or as individual compounds may be useful for managing Asian tiger mosquito, Ae. albopictus, populations.
Book
Full-text available
Culex o mosquito da cidade é uma obra dirigida ao aprimoramento de profissionais e técnicos que lidam com os mais variados aspectos do conhecimento nas áreas de ecologia, biologia, genética e controle de mosquitos vetores, especificamente o Culex quinquefasciatus, o pernilongo causador de incômodo em centros urbanos.
Article
The aim of this study was to evaluate the chemical composition and the larvicidal activity of Brunfelsia uniflora leaf and flower extracts against Aedes aegypti larvae. Twenty-four compounds were found in the leaf extract, and the major compounds were phytol (23.1%), 9,12,15-octadecatrienoic acid, ethyl ester (21.3%), and hexadecanoic acid, ethyl ester (12.8%). In the flower extract, twenty-four compounds were also identified and the major compounds were α-amyrin (35.7%), β-amyrin (16.4%), and (EE)-geranyl linalool (9.6%) by gas chromatography coupled to mass spectrometry. The larvicidal activity was evaluated by larval immersion test. The lethal concentrations (LC) obtained from leaf extract were LC50 = 4.89 and LC99.9 = 11.14 mg/mL and from flower extract were LC50 = 3.82 and LC99.9 = 11.03 mg/mL, and the positive control presented LC50 = 0.40 and LC99.9 = 1.14 mg/mL. Thus, B. uniflora extracts are promising alternatives to control A. aegypti larvae.
Article
Full-text available
This experimental research was aimed to study the effectiveness of basil chalk, black pepper chalk and wood vinegar chalk as ant repellents. There were five phases of research 1) preparing and extracting basil, black pepper, and wood vinegar, 2) producing chalks, 3) testing the effectiveness of the ant repellent chalks developed in a laboratory, 4) testing effectiveness of the ant repellent chalks in the house, and, 5) identifying chemical components by gas chromatography- mass spectrometry. Effectiveness of ant repellents were compared by one-way ANOVA, two-way ANOVA and Fisher LSD. Results showed that the effectiveness of black pepper, wood vinegar, and basil at concentration of 70% could repel 98.33, 99.33, and 94.50% of the ants, respectively. Black pepper chalk, basil chalk, and wood vinegar chalk could repel the ants in a house for 360, 180, 60 minutes, respectively. The most commonly found compound in basil chalk and wood vinegar chalk were acetic acid at concentration of 41.26% and 66.75%, respectively whereas the most common compound in black pepper chalk was caryophyllene (24.67%). In conclusion, these results demonstrated that basil chalk, black pepper chalk, and wood vinegar chalk were effective to repel the ants, but a limitation was they were not lasting for long time. For further study, other active compounds should be added extend the time of action and increase effectiveness of the ant repellents.
Chapter
Vapor repellency assessments were made for Aedes aegypti mosquitoes in a recently described microassay. Fragment screens of the acid and alcohol of transfluthrin showed no effect of the transfluthrin acid (TFA) alone, but it did enhance the repellency of the corresponding alcohol. It was further observed that TFA could synergize the repellent effects of transfluthrin, as well as its neurophysiological actions on the larval Drosophila melanogaster central nervous system (CNS). In contrast, TFA had no effect on imidacloprid-dependent neuroexcitation, perhaps indicating a dual action with transfluthrin on the nerve membrane sodium channels. Anthranilate and pyrazine repellents were fast-acting and were not synergized by TFA. Synthesis and repellency evaluation of the pure enantiomers of α-terpinyl isovalerate (α-TI) revealed a more slowly developing effect, but little EC50 difference from each isomer or the racemic mixture. Also, α-TI synergized the repellency of transfluthrin 10-fold, similar to that observed for TFA (7-fold). Taken together, these latter findings and the structural similarity of TFA to α-TI suggest they may work through common mechanisms and receptor(s), although experimental confirmation needs further study.
Chapter
This chapter describes the attributes of topical and spatial arthropod repellents (SRs) and the use of semi-field environments to evaluate their efficacy parameters. Topical arthropod repellents are chemical compounds placed directly on the exposed skin and require either contact by the biting arthropods or very close proximity to stop them from biting at the very last stages of their feeding processes. In contrast, SRs are volatile compounds that become airborne and prevent/discourage blood-seeking arthropods from making physical contact or even entering a defined space occupied by a potential host, thus protecting it from bites. The SRs can reduce biting arthropod density and ultimately human-vector contact over a larger area as long as the active ingredient concentration in air is high enough to repel or kill the arthropod vectors. The focus of this chapter is on the use of semi-field environments to conduct efficacy testing of commercially available arthropod repellent products and the development of novel ones. Semi-field studies serve as a bridge between laboratory and field studies, and not a replacement for either. Not only are semi-field environments useful for understanding the biology and behavior of biting arthropods, but also for developing methods of control and disease mitigation. The structure and types of experiments that have been conducted in semi-field environments found worldwide are briefly summarized. While the dimensions of these screened enclosures varied, they were sufficiently large to reflect an area that SRs are intended to protect under local ambient environmental conditions. SR studies conducted at the USDA Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, United States, past, current, and future are presented in more detail.
Article
Microencapsulation is a promising method for controlling and prolonging the release of safer, bio-based insect repellents, which can be used for protection against many vector-borne endemic diseases. Geraniol is an effective insect repellent; however, its encapsulation in gelatin/gum Arabic, and its long-term retention have not been studied to date. In this study, complex coacervation was used to obtain novel geraniol-containing microcapsules using gelatin/gum Arabic. The effect of processing conditions on the size and morphology of the microcapsules and the subsequent release properties was investigated. Optimal conditions included a coacervation pH of 4.45 and a crosslinking pH of 6.0. Lower mixing rates produced single core capsules with larger particle size (93 µm). Higher mixing rates resulted in multi-core capsules with smaller average particle sizes (34 µm). The geraniol contents of microcapsules were found to be 90%, 68%, and 73% for mixing rates of 700 RPM, 1000 RPM, and 1300 RPM, respectively. Microcapsule formulations showed excellent release profiles into humid air without any burst release, with retentions of 80%, 74%, and 76% at 26 days for mixing rates 700 RPM, 1000 RPM, and 1300 RPM, respectively. Encapsulation of geraniol results in longer-lasting retention compared to similar systems; hence it can be used as textile coatings for use in insect repellent clothing or incorporated into various carrier solutions for application as an area treatment. Our research highlights the possibility of tuning diffusion characteristics based on microcapsule morphology opening new applications for this technique.
Article
Full-text available
Pesticides are the main tactics for pest control because they reduce the pest population very fast and their efficiency does not depend on abiotic factors. However, the indiscriminate use of these substances can speed up the development of resistant populations and causing environmental contamination. Therefore, alternative methods of pest control are sought, such as the use of botanical compounds. Nanoencapsulation of volatile compounds has been shown to be an important tool that can be used to overcome the lack of stability of these compounds. In this work, we describe the preparation and characterization of chitosan nanoparticles functionalized with β-cyclodextrin containing carvacrol and linalool. The toxicity and biological activity were evaluated. Decreases of toxicity were observed when the compounds were nanoencapsulated. The nanoparticles presented insecticidal activity against the species Helicoverpa armigera (corn earworm) and Tetranychus urticae (spider mite). In addition, repellent activity and reduction in oviposition were observed for the mites.
Article
Full-text available
Five essential oils and nine of their components were compared to diethyl toluamide (DEET) for their repellent activity against the human body louse, Pediculus humanus humanus. The absolute or intrinsic repellency of the compounds was tested by applying the repellent to corduroy patches and comparing them with untreated patches. It was found that the most effective repellents were DEET and citronella, whose activity lasted at least 29 days. The activity of rosemary lasted at least 18 days and that of eucalyptus more than 8 days. The repellent activity of the oil components such as citronellal and geraniol lasted more than 15 and 8 days, respectively. DEET remained effective at a dilution of 1:32, geraniol at 1:8, citronella at 1:4 and rosemary and citronellal at 1:1. The comparative or standard repellency of the candidate repellents was examined with the aid of a new screening technique using hairs treated with ammonium bicarbonate which is attractive to lice. Using this technique it could be shown that the repellent activity of citronella and geraniol lasted 2 days and that of rosemary and citronellal for only one day. DEET was active for less than one day. Serial dilutions of these substances also revealed that citronella was the most potent repellent for lice, followed by citronellal, rosemary, geraniol and DEET. The differences however, were not significant.
Article
Full-text available
Four synthetic mosquito repellents (Autan [10% KBR3023], IR3535 [7.5%], Off! [15% deet], Skinsations [7% deet]) and eight natural (primarily plant extracts and/or essential oils) product-based repellents (Bite Blocker [2% soybean oil], ByGone, GonE!, Natrapel [10% citronella], Neem Aura, Sunswat, MosquitoSafe [25% geraniol], and Repel [26% p-menthane-3,8-diol]) were tested in the laboratory against Aedes albopictus Skuse, Culex nigripalpus Theobald, and Ochlerotatus triseriatus (Say). When estimated mean protection time (eMPT) responses for each repellent were averaged for all three mosquito species, Autan, Bite Blocker, Off!, and Repel prevented biting for > or =7.2 h; IR3535, MosquitoSafe, and Skinsations for 3.2-4.8 h; and ByGone, Natrapel, GonE, NeemAura, and SunSwat for 0.9-2.3 h. Against Ae. albopictus, the eMPT for Off! and Repel exceeded 7.0 h and ranged from 5.0 to 5.7 h for Autan, Bite Blocker, and Skinsations. Bygone, GonE, NeemAura, and SunSwat provided 0.2 h protection against Ae. albopictus and Oc. triseriatus, whereas Autan, Bite Blocker, Off., and Repel prevented bites by Oc. triseriatus for > or =7.3 h. All 12 repellents provided an eMPT > or =2.8 h against Cx. nigripalpus (maximum: 8.5 h for Bite Blocker). When the average eMPT for each repellent (for all species) was divided by the eMPT for 7% deet (Skinsations), the order of repellent effectiveness and the corresponding repellency index (R,) was Repel (1.7) > Bite Blocker (1.5) = Autan (1.5) = Off! (1.5) > Skinsations (1.0) > IR3535 (0.8) > MosquitoSafe (0.6) > Natrapel (0.5) > Neem Aura (0.3) = SunSwat (0.3) = Bygone (0.3) > GonE (0.2).
Article
Insect repellents are important tools for prevention of insect-borne diseases as well as painful or uncomfortable insect bites. The 2 most effective and widely used products are N, N-diethyl-3-methylbenzamide (deet), which is applied to exposed skin, and permethrin, which is applied to clothes. Both are safe when used according to directions. Other repellents, including a variety of plant-derived products, have also been used but generally have a weaker or shorter-lived repellent effect.
Article
The mugwortArtemisia vulgaris L. (Compositae: Anthemideae) contains insect repellents which can be released from the plant tissues by combustion. Work was carried out to isolate and identify the repellent compounds. The dried, pulverized whole plants were steam-distilled to give a repellent essential oil which was fractionated by column chromatography. Active fractions were analyzed by capillary GC and by combined GC-MS. A number of compounds, mainly monoterpenoids, were identified. When tested as repellents against the yellow fever mosquitoAedes aegypti L. (Diptera: Culicidae), (±)-linalool, (±)-camphor, (+)-camphor, (-)-camphor, isoborneol, (-)-borneol, terpinen-4-ol, and isobornyl acetate were active at 0.14 mg/cm2 or higher. Nonanone-3, (α+β)-thujone, and bornyl acetate were active at 0.28 mg/cm(2) or higher. β-Pinene, myrcene, α-terpinene, (+)- limonene, and cineole were active at 1.4 mg/cm(2). Of the repellent compounds identified, terpinen-4-ol was the most active and was as effective as dimethyl phthalate.
Article
Tests were conducted with 100 men and women subjects to compare their attractiveness to the yellow fever mosquito, Aedes aegypti (L.), and in addition to compare the times of protection against the mosquito when the same group of subjects was treated with deet. In previous experiments reported by Smith et al. (1963), Gouck and Bowman (1959), and Gouck and Gilbert (1962), only three to five test subjects were used. Our tests, however, were conducted with 50 subjects of each sex. Such factors as sex, age, weight, skin temperature, moisture output, and color were investigated to determine their influence on both attractiveness and protection time. Statistical significance of the values obtained was determined for the differences among individuals of the group and for the differences between men and women. In addition 37 women with menstrual cycles were tested before and after menses to determine the effects of physiological changes on the attractiveness of the subjects to the mosquito.
Article
The effect of temperature on deet was studied at temperature ranging from 26° to 50°C in 5° increments from 30 to 50°C and 4°C increments from 26 to 30°C. A highly significant (P < 0,01) negative correlation (r = −0.9552) was found between protection times and temperatures. Five other repellents besides deet. viz. ethyl hexanediol, dimethyl phthalate (DMP), butyl 3,4-dihydro-2,2-di-methyl 4-oxo-2H-pran-6-carboxylate, and hexamethyleneimine butane sulfomide: were tested for protection time at 40°C and compared with their respective protection times at room temperature (26°C). A highly significant (P < 0,01) positive correlation was obtained (r = +0,9821) between the data at the two temperatures. Using the ratio of the protection time at 40°C to that at 26°C as an index for resistance, hexamethyleneimine butane sulfonamide withstood heat the most and ethyl hexanediol the least. Use of elevated temperature a quick method of screening insect repellents is discussed.
Article
Attention has recently been focussed on the problem of why mosquitoes feed on some people more than others. In this paper, investigations of selective feeding by mosquitoes of the Anopheles gambiae Giles complex conducted in two villages in the Gambia are reported. Fed mosquitoes were collected from the bed nets of 35 groups of people who normally sleep together, for example mothers and infants or two children or two adults. A total of 2339 meals was analysed using haptoglobin or ABO typing to determine from which individual each meal had been obtained. The results showed that the proportion of feeds upon an individual in a group can be associated with the proportion of the total surface area or weight of the group contributed by that individual. The incidence of multiple feeding was between 3 and 6%. The results are discussed in relation to host selection by mosquitoes and their significance for models of malaria epidemiology.
Article
A review on the reported uses of chemicals derived from botanical sources is presented, along with the part of the plant used for extraction, the mosquito species studied and the bioactivity observed for 344 plant species. Examples of phytochemicals evaluated against mosquitoes as general toxicants, growth and reproduction inhibitors, repellents and ovipositional deterrents are given. The effects of mosquito species and life stage specificity, solvents used for extraction, phototoxic activity and the geographical source from where the plant compounds are derived are discussed.
Article
Descriptions of the World Health Organization standard methods of assessing susceptibility or resistance in larval and in adult mosquitoes are presented, and the evaluation of their results are discussed. Other susceptibility test methods are also mentioned, including those based on esterase zymograms. Recent work on the biochemical mechanisms of resistance and cross-resistance are reviewed, along with possible countermeasures for the problem of mosquito resistance, now known in 113 species of culicines and anophelines.
Article
Extensive animal testing and 30 years of human experience have established the general safety of DEET when applied episodically to skin or bedclothes. Local and systemic toxic and allergic reactions to DEET have been observed in man. Three weeks prior to admission, for the purpose of self-medication, a 30 year old man began daily applications of the insect repellant, DEET followed by a 1-2 hour period in a light-bulb heated box. Sedation and incoherence were noted for short periods following each application session. Aggressiveness and psychotic ideation led to hospital admission where he displayed psychomotor hyperactivity, rapid and pressured speech, tangentiality, flight of ideas, and grandiose delusions. Treatment was begun with haloperidol. Clinical improvement was complete within 6 days, atypical for classic endogenous mania. Drug and metabolites were identified in the urine more than 2 weeks after the last drug application.
Article
Deet is considered to be the best "all around" insect repellent ever developed and is the most widely used insect repellent in the world. Since its first use in a consumer product in 1956, billions of applications have been made to human skin. Information about the safety of deet comes from the human clinical literature, animal toxicology studies, and poison control centers' experiences with deet. The clinical literature reports the association of deet with neurotoxicity in 14 individuals. Three of the cases resulted in death, whereas all of the other patients completely recovered. The exact role of deet in the toxicity reported is difficult to determine from the reports. Recently reported animal safety studies have examined potential neurotoxicity following multigenerational dosing. Effects on the nervous system were only seen when generalized toxicity was also observed. Thus deet is not a selective neurotoxin. Important information about deet also comes from an investigation into the reports of adverse affects reported to 71 poison control centers in the USA. An important conclusion from this study is that there is no evidence that increasing deet concentration has any effect on the severity of the symptoms reported. The vast majority of reported cases had either no symptoms or ones that resolved rapidly. In conclusion, a thorough examination of all information available indicates that the risk of serious adverse effects following the use of deet is extremely low.
Article
We assessed the efficacy of 3% citronella candles and 5% citronella incense in protecting subjects from bites of Aedes spp. under field conditions. The study was conducted in a deciduous woodlot in Guelph, Ontario, Canada from July 26 to August 10, 1995. Eight subjects, dressed identically, were assigned to one of 8 positions on a grid within the study area. Two citronella candles, 2 citronella incense, 2 plain unscented candles, or no candles (i.e., nontreated controls) were assigned to 2 positions on the grid each evening. Subjects conducted 5-min biting counts at each position and performed 16 biting counts per evening. On average, subjects received 6.2 +/- 0.4, 8.2 +/- 0.5, 8.2 +/- 0.4, and 10.8 +/- 0.5 bites/ 5 min at positions with citronella candles, citronella incense, plain candles, and no candles, respectively. Although significantly fewer bites were received by subjects at positions with citronella candles and incense than at nontreated locations, the overall reduction in bites provided by the citronella candles and incense was only 42.3 and 24.2%, respectively.
Article
N,N-Diethyl-m-toluamide, an effective tick repellent, when applied to the skin, is the major component of essentially all of the products marketed for this purpose. It is used by about 30% of the US population, and by 23-29% of children in this population. Reports of neurologic adversity and death are rare and primarily involve children, but the dose relationship between N,N-diethyl-m-toluamide exposure and the symptoms reported in the clinical literature is difficult to establish. Animal toxicology studies, clinical reports of neurological adversities in children and adults, and the available Poison Control Center records have been reviewed in an effort to understand the relationship between the N,N-diethyl-m-toluamide exposure and reported adverse events. Based on (1) the animal toxicology database on N,N-diethyl-m-toluamide, (2) the reports of adverse events in humans, and (3) the possible alternate etiologies for the symptoms reported in most patients, the risk of adversity from label-directed use of N,N-diethyl-m-toluamide appears low. Future efforts should focus on the prospective collection of adversity data with special attention paid to the documentation of clinical effects.
Article
The diel landing/biting periodicity of the Trinidad strain of Aedes aegypti (L.) was monitored using human-bait during January-August 1999. Hourly light intensities were measured both indoors and outdoors at both urban and rural sites. The periodicity of females was diurnal and nocturnal, with 90% arriving during daylight and twilight and 10% during the night. The pattern of landing was trimodal, with consistent peaks at 0700 h, 1100 h and 1700 h. The diel periodicities at indoor and outdoor urban sites were virtually identical. In contrast, the periodicities in rural areas differed, with no nocturnal activities being recorded at indoor and outdoor sites. At both urban and rural sites, larger numbers of adults were collected outside than inside houses. A significant correlation between light intensities and mosquito landing patterns was observed. The implications of the changing landing patterns of Ae. aegypti within urban areas are discussed in light of the epidemiology and control of dengue fever in Trinidad.
Article
Volatile oils extracted by steam distillation from four plant species (turmeric (Curcuma longa), kaffir lime (Citrus hystrix), citronella grass (Cymbopogon winterianus) and hairy basil (Ocimum americanum)), were evaluated in mosquito cages and in a large room for their repellency effects against three mosquito vectors, Aedes aegypti, Anopheles dirus and Culex quinquefasciatus. The oils from turmeric, citronella grass and hairy basil, especially with the addition of 5% vanillin, repelled the three species under cage conditions for up to eight hours. The oil from kaffir lime alone, as well as with 5% vanillin added, was effective for up to three hours. With regard to the standard repellent, deet alone provided protection for at least eight hours against Ae. aegypti and Cx. quinquefasciatus, but for six hours against An. dirus. However, deet with the addition of 5% vanillin gave protection against the three mosquito species for at least eight hours. The results of large room evaluations confirmed the responses for each repellent treatment obtained under cage conditions. This study demonstrates the potential of volatile oils extracted from turmeric, citronella grass and hairy basil as topical repellents against both day- and night-biting mosquitoes. The three volatile oils can be formulated with vanillin as mosquito repellents in various forms to replace deet (N,N-diethyl-3-methylbenzamide), the most common chemical repellent currently available.
Article
The effects of four plant extract formulations on the orientation and survival of subterranean termites were tested. In choice experiments, extract-treated filter paper had a significantly repellent effect on groups of Reticulitermes santonensis De Feytaud, R. virginicus (Banks), Coptotermes formosanus Shiraki, and Schedorhinotermes intermedius Breinli. There was no species-specific difference in avoidance behavior toward the tested concentrations. No-choice experiments revealed toxic properties of all investigated extracts by contact or airborne compounds against R. santonensis. However, high termite mortality was only achieved by forced direct or forced indirect exposure to the plant material, Feeding deterrence or digestive toxicity could not be judged in these experiments. One of the extracts was efficiently used for soil treatments to protect a food substrate against R. santonenis infestation. Extract-treated barriers in the experiments did not affect mortality compared with control trials but prevented termites from penetrating treated soil.
Article
Essential oils of Eulcalyptus globulus, Lavender officinalis, Rosemarinus officinalis, and Thymus vulgaris were examined for their repellent activities against Culex pipiens pallens. All 4 essential oils effectively repelled adult mosquitoes on hairless mice. Essential oil of T. vulgaris (thyme) had potent repellent activity within the tested materials, with a protection rate of 91% at a concentration of 0.05% topical treatment. Thyme essential oil significantly extended the duration of protection until 3 bites by mosquitoes. With gas chromatography-mass spectrometry analysis, thyme essential oil was a rich source of 5 monoterpenes, including in descending order thymol, p-cymene, carvacrol, linalool, and alpha-terpinene. These 5 monoterpenes also were assessed to determine their repellent activities to the mosquitoes. alpha-Terpinene had a potent repellent activity with a protection rate of 97% at a concentration of 0.05% topical treatment. Additionally, carvacrol and thymol showed an equivalent level of repellency. A spray-type solution containing 2% alpha-terpinene was tested for its repellent activity against Cx. pipiens. This solution showed stronger repellent activity than the currently used repellent N,N-diethyl-m-methylbenzamide (deet).
Article
Five monoterpenes (carvacrol, p-cymene, linalool, alpha-terpinene, and thymol) derived from the essential oil of thyme (Thymus vulgaris) were examined for their repellency against the mosquito Culex pipiens pallens. All 5 monoterpenes effectively repelled mosquitoes based on a human forearm bioassay. Alpha-terpinene and carvacrol showed significantly greater repellency than a commercial formulation, N,N-diethyl-m-methylbenzamide (deet), whereas thymol showed similar repellency to that of deet. The duration of repellency after application for all these monoterpenes was equal to or higher than that of deet. These findings indicate that a spray-type solution containing 2% alpha-terpinene may serve as an alternative mosquito repellent.
Techniques for evaluating repellents Insect Repellents: Principles, Methods and Uses Handbook of Pesticide Toxicology
  • M Govere
  • D N Durrheim
Govere, M. and D.N. Durrheim. 2007. Techniques for evaluating repellents. In: M. Debboun, S.P. Frances, and D. Strickman (eds). Insect Repellents: Principles, Methods and Uses. pp. 147-159. CRC press, Boca Raton, FL. Hayes, W.J. and E.R. Laws Jr. (eds.) 1991. Handbook of Pesticide Toxicology. Volume l: General Principles. 497 pp. New York, NY, Academic Press.
Insect Repellents: Principles, Methods and Uses. pp. 103-110 Repellent and toxic effects of plant extracts on subterranean termites (Isoptera: Rhinotermitidae)
  • Strickman Boca Raton
  • Fl Blaske
  • H Hertel
Strickman (eds). Insect Repellents: Principles, Methods and Uses. pp. 103-110. CRC Press, Boca Raton, FL. Blaske, V.U. and H. Hertel. 2001. Repellent and toxic effects of plant extracts on subterranean termites (Isoptera: Rhinotermitidae). J. Econ. Entomol. 94: 1200–1208.
Evaporation rates and protection times of mosquito repellents
  • M L Gabel
  • T S Spencer
  • W A Akers
Gabel, M.L., T.S. Spencer, and W.A. Akers. 1976. Evaporation rates and protection times of mosquito repellents. Mosq. News. 36: 141-146.
Techniques for evaluating repellents Insect Repellents: Principles, Methods and Uses
  • M Govere
  • D N Durrheim
Govere, M. and D.N. Durrheim. 2007. Techniques for evaluating repellents. In: M. Debboun, S.P. Frances, and D. Strickman (eds). Insect Repellents: Principles, Methods and Uses. pp. 147-159. CRC press, Boca Raton, FL.
Handbook of Pesticide Toxicology. Volume l: General Principles. 497 pp
  • W J Hayes
  • E R Laws Jr
Hayes, W.J. and E.R. Laws Jr. (eds.) 1991. Handbook of Pesticide Toxicology. Volume l: General Principles. 497 pp. New York, NY, Academic Press.
Insect Repellents: Principles, Methods and Uses. pp. 103-110
  • Strickman
Strickman (eds). Insect Repellents: Principles, Methods and Uses. pp. 103-110. CRC Press, Boca Raton, FL.
Health risks and benefits of insect repellents
  • Godard
Repellency of essential oils and their components to the human body louse, Pediculus humanus humanus
  • Mumcuoglu
Evaporation rates and protection times of mosquitorepellents
  • Gabel