An insect repellent (also commonly called "bug spray" or "bug deterrent") is a substance applied to the skin, clothing, or other surfaces to discourage

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s (and

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s in general) from landing or climbing on that surface. Insect repellents help prevent and control the outbreak of insect-borne (and other

-bourne) diseases such as

malaria Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...

Lyme disease Lyme disease, also known as Lyme borreliosis, is a tick-borne disease caused by species of ''Borrelia'' bacteria, Disease vector, transmitted by blood-feeding ticks in the genus ''Ixodes''. It is the most common disease spread by ticks in th ...

dengue fever Dengue fever is a mosquito-borne disease caused by dengue virus, prevalent in tropical and subtropical areas. Asymptomatic infections are uncommon, mild cases happen frequently; if symptoms appear, they typically begin 3 to 14 days after i ...

bubonic plague Bubonic plague is one of three types of Plague (disease), plague caused by the Bacteria, bacterium ''Yersinia pestis''. One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and ...

river blindness Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic worm ''Onchocerca volvulus''. Symptoms include severe itching, bumps under the skin, and blindness. It is the second-most common cause of blindne ...

, and West Nile fever. Pest animals commonly serving as vectors for disease include insects such as

flea Flea, the common name for the order (biology), order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by hematophagy, ingesting the blood of their hosts. Adult f ...

, fly, and

mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

; and ticks (arachnids). Some insect repellents are

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s (bug killers), but most simply discourage insects and send them flying or crawling away.

Effectiveness

Synthetic repellents tend to be more effective and/or longer lasting than "natural" repellents. For protection against ticks and mosquito bites, the U.S.

Centers for Disease Control The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency under the Department of Health and Human Services (HHS), and is headquartered in Atlanta, ...

(CDC) recommends DEET, icaridin (picaridin, KBR 3023), oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), IR3535 and 2-undecanone with the caveat that higher percentages of the active ingredient provide longer protection. In 2015, researchers at New Mexico State University tested 10 commercially available products for their effectiveness at repelling mosquitoes. The known active ingredients tested included DEET (at various concentrations), geraniol, p-menthane-3-8-diol (found in lemon eucalyptus oil),

thiamine Thiamine, also known as thiamin and vitamin B1, is a vitamin – an Nutrient#Micronutrients, essential micronutrient for humans and animals. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosp ...

, and several oils (soybean, rosemary, cinnamon, lemongrass, citronella, and lemon eucalyptus). Two of the products tested were fragrances where the active ingredients were unknown. On the mosquito ''

Aedes aegypti ''Aedes aegypti'' ( or from Greek 'hateful' and from Latin, meaning 'of Egypt'), sometimes called the Egyptian mosquito, dengue mosquito or yellow fever mosquito, is a mosquito that spreads diseases like dengue fever, yellow fever, malar ...

'', only one repellent that did not contain DEET had a strong effect for the duration of the 240 minutes test: a lemon eucalyptus oil repellent. However,

Victoria's Secret Victoria's Secret is an American lingerie, clothing and beauty products, beauty retailer. Founded in 1977 by a Stanford graduate student and his wife, Roy Raymond, Roy and Gaye Raymond, the company's five lingerie stores were sold to Les Wexner i ...

Bombshell, a perfume not advertised as an insect repellant, performed effectively during the first 120 minutes after application. In one comparative study from 2004, IR3535 was as effective or better than DEET in protection against ''Aedes aegypti'' and ''Culex quinquefasciatus'' mosquitoes. Other sources (official publications of the associations of German physicians as well as of German druggists) suggest the contrary and state DEET is still the most efficient substance available and the substance of choice for stays in malaria regions, while IR3535 has little effect. However, some plant-based repellents may provide effective relief as well.

Essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...

repellents can be short-lived in their effectiveness. A test of various insect repellents by an independent

consumer organization Consumer organizations are advocacy groups that seek to protect people from corporate abuse like unsafe products, predatory lending, false advertising, astroturfing and pollution. Consumer Organizations may operate via protests, litigation, Adver ...

found that repellents containing DEET or icaridin are more effective than repellents with "natural" active ingredients. All the synthetics gave almost 100% repellency for the first 2 hours, where the natural repellent products were most effective for the first 30 to 60 minutes, and required reapplication to be effective over several hours. Although highly toxic to cats, permethrin is recommended as protection against mosquitoes for clothing, gear, or bed nets. In an earlier report, the CDC found oil of lemon eucalyptus to be more effective than other plant-based treatments, with a similar effectiveness to low concentrations of DEET. However, a 2006 published study found in both cage and field studies that a product containing 40% oil of lemon eucalyptus was just as effective as products containing high concentrations of DEET. Research has also found that neem oil is mosquito repellent for up to 12 hours. Citronella oil's mosquito repellency has also been verified by research, including effectiveness in repelling ''

'', but requires reapplication after 30 to 60 minutes. There are also products available based on sound production, particularly

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

(inaudibly high-frequency sounds) which purport to be insect repellents. However, these electronic devices have been shown to be ineffective based on studies done by the United States Environmental Protection Agency and many universities.

Safety issues

For humans

Children may be at greater risk for adverse reactions to repellents, in part, because their exposure may be greater. Children can be at greater risk of accidental eye contact or ingestion. As with chemical exposures in general, pregnant women should take care to avoid exposures to repellents when practical, as the

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

may be vulnerable. Some experts also recommend against applying chemicals such as DEET and sunscreen simultaneously since that would increase DEET penetration. Canadian researcher, Xiaochen Gu, a professor at the University of Manitoba's faculty of Pharmacy who led a study about mosquitos, advises that DEET should be applied 30 or more minutes later. Gu also recommends insect repellent sprays instead of lotions which are rubbed into the skin "forcing molecules into the skin". Regardless of which repellent product used, it is recommended to read the

label A label (as distinct from signage) is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product. Labels are most often affixed to packaging and containers using an adhesive, or sewing when affix ...

before use and carefully follow directions. Usage instructions for repellents vary from country to country. Some insect repellents are not recommended for use on younger children. In the DEET Reregistration Eligibility Decision (RED) the

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent agency of the United States government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on De ...

(EPA) reported 14 to 46 cases of potential DEET associated

seizures A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

, including 4 deaths. The EPA states: "... it does appear that some cases are likely related to DEET

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacteria, bacterium, or plant, as well as the effect o ...

", but observed that with 30% of the US population using DEET, the likely seizure rate is only about one per 100 million users. The Pesticide Information Project of Cooperative Extension Offices of

Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

states that, "

Everglades National Park Everglades National Park is a List of national parks of the United States, national park of the United States that protects the southern twenty percent of the original Everglades in Florida. The park is the largest tropical wilderness in the Un ...

employees having extensive DEET exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers".Deet
/ref> The EPA states that citronella oil shows little or no toxicity and has been used as a topical insect repellent for 60 years. However, the EPA also states that citronella may irritate skin and cause

dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

in certain individuals. Canadian regulatory authorities concern with citronella based repellents is primarily based on data-gaps in

toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating ex ...

, not on incidents. Within countries of the European Union, implementation of Regulation 98/8/EC, commonly referred to as the Biocidal Products Directive, has severely limited the number and type of insect repellents available to European consumers. Only a small number of active ingredients have been supported by manufacturers in submitting dossiers to the EU Authorities. In general, only formulations containing DEET, icaridin (sold under the trade name Saltidin and formerly known as Bayrepel or KBR3023), IR3535 and citriodiol ( p-menthane-3,8-diol) are available. Most "natural" insect repellents such as citronella, neem oil, and herbal extracts are no longer permitted for sale as insect repellents in the EU due to their lack of effectiveness; this does not preclude them from being sold for other purposes, as long as the label does not indicate they are a

biocide A biocide is defined in the European legislation as a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. The US Environmental Protection Agency (EPA) uses a sli ...

(insect repellent).

Toxicity for other animals

A 2018 study found that Icaridin, is highly toxic to

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

larvae A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...

, in what the authors described as conservative exposure doses. The LC50 standard was additionally found to be completely inadequate in the context of finding this result.

Permethrin Permethrin is a medication and an insecticide. As a medication, it is used to treat scabies and lice. It is applied to the skin as a cream or lotion. As an insecticide, it can be sprayed onto outer clothing or mosquito nets to kill the insects ...

is highly toxic to cats but not to dogs or humans.

Common insect repellents

Common synthetic insect repellents

Benzaldehyde Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is among the simplest aromatic aldehydes and one of the most industrially useful. It is a colorless liquid with a characteristic almond-li ...

, for bees * Butopyronoxyl (trade name Indalone). Widely used in a "6-2-2" mixture (60% Dimethyl phthalate, 20% Indalone, 20% Ethylhexanediol) during the 1940s and 1950s before the commercial introduction of DEET * DEET (''N'',''N''-diethyl-''m''-toluamide) the most common and effective insect repellent * Dimethyl carbate * Dimethyl phthalate, not as common as it once was but still occasionally an active ingredient in commercial insect repellents * Ethyl butylacetylaminopropionate (IR3535 or 3- 'N''-Butyl-''N''-acetylaminopropionic acid, ethyl ester) * Ethylhexanediol, also known as Rutgers 612 or "6–12 repellent", discontinued in the US in 1991 due to evidence of causing developmental defects in animals * Icaridin, also known as picaridin, Bayrepel, and KBR 3023 considered equal in effectiveness to DEET * Methyl anthranilate and other anthranilate-based insect repellents * Metofluthrin *

is a contact

rather than a repellent * SS220 is a repellent being researched that has shown promise to provide significantly better protection than DEET * Tricyclodecenyl allyl ether, a compound often found in synthetic perfumes

Common natural insect repellents

* Beautyberry (''Callicarpa'') leaves *

Birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...

tree bark is traditionally made into tar. Combined with another oil (e.g., fish oil) at 1/2 dilution, it is then applied to the skin for repelling mosquitos * Bog myrtle (''Myrica gale'') *

Catnip ''Nepeta cataria'', commonly known as catnip and catmint, is a species of the genus ''Nepeta'' in the mint family, native plant, native to southern and eastern Europe, northern parts of the Middle East, and Central Asia. It is widely naturalis ...

oil whose active compound is Nepetalactone * Citronella oil (citronella candles are not effective) *

of the lemon eucalyptus (''Corymbia citriodora'') and its active compound p-menthane-3,8-diol (PMD) * Lemongrass *

Neem oil Neem oil, also known as margosa oil, is a vegetable oil pressed from the fruits and seeds of the neem (''Azadirachta indica''), a tree which is indigenous to the Indian subcontinent and has been introduced to many other areas in the tropics. It ...

Tea tree oil Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh, camphoraceous odour and a colour that ranges from pale yellow to nearly colourless and clear. It is derived from the leaves of the tea tree, '' Melaleuca alternif ...

from the leaves of '' Melaleuca alternifolia'' *

Tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...

Insect repellents from natural sources

Several natural ingredients are certified by the

as insect repellents, namely

catnip ''Nepeta cataria'', commonly known as catnip and catmint, is a species of the genus ''Nepeta'' in the mint family, native plant, native to southern and eastern Europe, northern parts of the Middle East, and Central Asia. It is widely naturalis ...

oil, oil of lemon eucalyptus (OLE) (and its active ingredient p-Menthane-3,8-diol), oil of citronella, and 2-Undecanone, which is usually produced synthetically but has also been isolated from many plant sources. Many other studies have also investigated the potential of natural compounds from plants as insect repellents. Moreover, there are many preparations from naturally occurring sources that have been used as a repellent to certain insects. Some of these act as

insecticides Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, in ...

while others are only repellent. Below is a list of some natural products with repellent activity: * '' Achillea alpina'' (mosquitos) * alpha- terpinene (mosquitos) * '' Andrographis paniculata'' extracts (mosquito) * Basil ** Sweet basil (''

Ocimum basilicum Basil (, ; , ; ''Ocimum basilicum'' (, )), also called great basil, is a culinary herb of the family Lamiaceae (mints). It is a hardiness (plants), tender plant, and is used in cuisines worldwide. In Western cuisine, the generic term "basil" r ...

'') *

Breadfruit Breadfruit (''Artocarpus altilis'') is a species of flowering tree in the mulberry and jackfruit family ( Moraceae) believed to have been selectively bred in Polynesia from the breadnut ('' Artocarpus camansi''). Breadfruit was spread into ...

(Insect repellent, including mosquitoes) * '' Callicarpa americana'' ( beautyberry) * Camphor (mosquitoes) *

Carvacrol Carvacrol, or cymophenol, C6H3(CH3)(OH)C3H7, is a monoterpene, monoterpenoid phenol. It has a characteristic pungent, warm odor of oregano. Natural occurrence Carvacrol is present in the essential oil of ''Origanum vulgare'' (oregano), oil of t ...

(mosquitos) * Castor oil (''Ricinus communis'') (mosquitos) *

oil (''Nepeta'' species) ( nepetalactone against mosquitos) *

Cedar oil Cedar oil, also known as cedarwood oil, is an essential oil derived from various types of Pinophyta, conifers, most in the Pinaceae, pine or Cupressaceae, cypress List of trees and shrubs by taxonomic family, botanical families. It is produced fro ...

(mosquitos, moths) * An example of ineffective herbal insect repellent

Celery Celery (''Apium graveolens'' Dulce Group or ''Apium graveolens'' var. ''dulce'') is a cultivated plant belonging to the species ''Apium graveolens'' in the family Apiaceae that has been used as a vegetable since ancient times. The original wild ...

extract (''Apium graveolens'') (mosquitos) In clinical testing an extract of celery was demonstrated to be at least equally effective to 25% DEET, although the commercial availability of such an extract is not known. *

Cinnamon Cinnamon is a spice obtained from the inner bark of several tree species from the genus ''Cinnamomum''. Cinnamon is used mainly as an aromatic condiment and flavouring additive in a wide variety of cuisines, sweet and savoury dishes, biscuits, b ...

( leaf oil kills mosquito larvae) * Citronella oil (repels mosquitos) (contains insect repelling substances, such as citronellol and geraniol) * Clove oil (mosquitos) * D-

Limonene Limonene () is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the essential oil of citrus fruit peels. The (+)-isomer, occurring more commonly in nature as the fragrance of oranges, ...

(ticks, fleas, flies, mosquitoes, and other insects) (widely used in insect repellents for pets) * Eucalyptus oil (70%+ eucalyptol), (cineol is a synonym), mosquitos, flies, dust mites In the U.S., eucalyptus oil was first registered in 1948 as an insecticide and miticide. *

Fennel Fennel (''Foeniculum vulgare'') is a flowering plant species in the carrot family. It is a hardy, perennial herb with yellow flowers and feathery leaves. It is indigenous to the shores of the Mediterranean but has become widely naturalized ...

oil (''Foeniculum vulgare'') (mosquitos) *

Garlic Garlic (''Allium sativum'') is a species of bulbous flowering plants in the genus '' Allium''. Its close relatives include the onion, shallot, leek, chives, Welsh onion, and Chinese onion. Garlic is native to central and south Asia, str ...

(''Allium sativum'') (Mosquito, rice weevil, wheat flour beetle) * Geranium oil (also known as '' Pelargonium graveolens'') * Hinokitiol (ticks, mosquitos, larvae) *

Lavender ''Lavandula'' (common name lavender) is a genus of 47 known species of perennial flowering plants in the sage family, Lamiaceae. It is native plant, native to the Old World, primarily found across the drier, warmer regions of the Mediterranean ...

(ineffective alone, but measurable effect in certain repellent mixtures) * Lemon eucalyptus (''Corymbia citriodora'') essential oil and its active ingredient p-menthane-3,8-diol (PMD) * Lemongrass oil (''Cymbopogon'' species) (mosquitos) ** East-Indian lemon grass ('' Cymbopogon flexuosus'') * Linalool (ticks, fleas, mites, mosquitoes, spiders, cockroach) * Marjoram (spider mites '' Tetranychus urticae'' and '' Eutetranychus orientalis'') * Mint (

menthol Menthol is an organic compound, specifically a Monoterpene, monoterpenoid, that occurs naturally in the oils of several plants in the Mentha, mint family, such as Mentha arvensis, corn mint and peppermint. It is a white or clear waxy crystallin ...

is active chemical.) ( Mentha sp.) *

(''Azadirachta indica'') (Repels or kills mosquitos, their larvae and a plethora of other insects including those in agriculture) * Nootkatone (ticks, mosquitoes and other insects) *

Oleic acid Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish due to the presence of impurities. In chemical terms, oleic acid is cl ...

, repels bees and

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

s by simulating the " smell of death" produced by their decomposing corpses. * Pennyroyal (''Mentha pulegium'') (mosquitos, fleas,) but very toxic to pets * Peppermint (''Mentha'' x ''piperita'') (mosquitos) * Pyrethrum (from ''Chrysanthemum'' species, particularly ''C. cinerariifolium'' and ''C. coccineum'') * Rosemary (''Rosmarinus officinalis'') (mosquitos) * Spanish Flag (''

Lantana camara ''Lantana camara'' (common lantana) is a species of flowering plant in the verbena family (Verbenaceae), native to the American tropics. It is a very adaptable species, which can inhabit a wide variety of ecosystems; once it has been introduced i ...

'') (against Tea Mosquito Bug, '' Helopeltis theivora'') *

from the leaves of '' Melaleuca alternifolia'' *

Thyme Thyme () is a culinary herb consisting of the dried aerial parts of some members of the genus ''Thymus (plant), Thymus'' of flowering plants in the mint family Lamiaceae. Thymes are native to Eurasia and north Africa. Thymes have culinary, medici ...

(''Thymus'' species) (mosquitos) * Yellow nightshade ('' Solanum villosum''), berry juice (against '' Stegomyia aegypti'' mosquitos)

Less effective methods

Some old studies suggested that the ingestion of large doses of

(vitamin B₁) could be effective as an

oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or ora ...

insect repellent against mosquito bites. However, there is now conclusive evidence that thiamin has no efficacy against mosquito bites. Some claim that plants such as wormwood or sagewort, lemon balm, lemon grass, lemon thyme, and the mosquito plant (Pelargonium) will act against mosquitoes. However, scientists have determined that these plants are "effective" for a limited time only when the leaves are crushed and applied directly to the skin. There are several, widespread, unproven theories about mosquito control, such as the assertion that vitamin B, in particular B₁ (thiamine),

garlic Garlic (''Allium sativum'') is a species of bulbous flowering plants in the genus '' Allium''. Its close relatives include the onion, shallot, leek, chives, Welsh onion, and Chinese onion. Garlic is native to central and south Asia, str ...

, ultrasonic devices or

incense Incense is an aromatic biotic material that releases fragrant smoke when burnt. The term is used for either the material or the aroma. Incense is used for aesthetic reasons, religious worship, aromatherapy, meditation, and ceremonial reasons. It ...

can be used to repel or control mosquitoes. Moreover, manufacturers of "mosquito repelling" ultrasonic devices have been found to be fraudulent,Lentek International-08/28/02
/ref> and their devices were deemed "useless" according to a review of scientific studies.

Alternatives to repellent

People can reduce the number of mosquito bites they receive (to a greater or lesser degree) by: * Using a mosquito net * Wearing long clothing that covers the skin and is tucked in to seal up holesNatural & Alternative Mosquito Repellents
/ref> * Avoiding the outdoors during

dawn Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the diffuse sky radiation, appearance of indirect sunlight being Rayleigh scattering, scattered in Earth's atmosphere, when the centre of the Sun's disc ha ...

and

dusk Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall.''The Random House College Dictionary'', "dusk". At predusk, during early to intermediate stages of twilight, enoug ...

, when mosquitos are most active * Keeping air moving to prevent mosquitos from landing, such as by using a fan * Wearing light-colored clothing (light objects are harder for mosquitos to detect)Micro Wave: Why Mosquitoes Bite You More Than Your Friends
/ref> * Reducing exercise, which reduces output of

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

used by mosquitos for detection

History

Testing and scientific certainty were desired at the end of the 1940s. To that end products meant to be used by humans were tested with model animals to speed trials. Eddy & McGregor 1949 and Wiesmann & Lotmar 1949 used

mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

, Wasicky et al. 1949 canaries and

guinea pig The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy ( ), is a species of rodent belonging to the genus ''Cavia'', family Caviidae. Animal fancy, Breeders tend to use the name "cavy" for the ani ...

s, Kasman et al. 1953 also guinea pigs, Starnes & Granett 1953

rabbit Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated ...

s, and many used

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

References

External links

2011 review of studies of plant-based mosquito repellents – NIH

* * * * ttps://archive.today/20121212064202/http://www.ars-grin.gov/cgi-bin/duke/chemact.pl?INSECT-REPELLENT+BORNEOL Dr. Duke's Phytochemical and Ethnobotanical Databases(plant parts with Insect-repellent Activity from the chemical Borneol)
Mosquito repellents; Florida U

{{Portal bar, Insects Chemical ecology Hiking equipment Household chemicals mt:Repellent tal-insetti