An
insect repellent is a substance applied to skin, clothing, or other surfaces which discourages
insectInsects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s (and
arthropodAn arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s in general) from landing or climbing on that surface. There are also insect repellent products available based on sound production, particularly
ultrasoundUltrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
(inaudibly high frequency sounds). These electronic devices have been shown to have no effect as a mosquito repellent by studies done by the EPA and many universities.
Insect repellents help prevent and control the outbreak of insect-borne diseases such as
malariaMalaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...
,
Lyme diseaseLyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
,
dengue feverDengue fever , also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles...
,
bubonic plaguePlague is a deadly infectious disease that is caused by the enterobacteria Yersinia pestis, named after the French-Swiss bacteriologist Alexandre Yersin. Primarily carried by rodents and spread to humans via fleas, the disease is notorious throughout history, due to the unrivaled scale of death...
, and West Nile fever. Pest animals commonly serving as vectors for disease include the insects
fleaFlea is the common name for insects of the order Siphonaptera which are wingless insects with mouthparts adapted for piercing skin and sucking blood...
,
flyTrue flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
, and
mosquitoMosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
; and the arachnid
tickTicks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
.
Common insect repellents
- DEET
N,N-Diethyl-meta-toluamide, abbreviated DEET, is a slightly yellow oil. It is the most common active ingredient in insect repellents...
(N,N-diethyl-m-toluamide)
- Essential oil
An essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile oils, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove...
of the lemon eucalyptus (Corymbia citriodora) and its active compound p-menthane-3,8-diolp-Menthane-3,8-diol, also known as para-menthane-3,8-diol, PMD, or Menthoglycol, is an active ingredient used in insect repellents. It smells similar to menthol and acts as a coolant. PMD is found in very small quantities in the essential oil within leaves of the Eucalyptus citriodora tree...
(PMD)
- Icaridin
Icaridin, also known as picaridine, KBR 3023, under the INCI name hydroxyethyl isobutyl piperidine carboxylate, and the trade names Bayrepel and Saltidin, is an insect repellent...
, also known as picaridin, Bayrepel, and KBR 3023
- Nepetalactone
Nepetalactone is an organic compound, first isolated from the plant catnip , which acts as a cat attractant. Nepetalactone is bicyclic terpenoid, i.e., it is a ten-carbon compound derived from isoprene with two fused rings, a cyclopentane and a lactone. The structure and the effects of the compound...
, also known as "catnip oil"
- Citronella oil
Citronella oil is one of the essential oils obtained from the leaves and stems of different species of Cymbopogon. The oil is used extensively as a source of perfumery chemicals such as citronellal, citronellol and geraniol...
- Permethrin
Permethrin is a common synthetic chemical, widely used as an insecticide, acaricide, and insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to...
- Neem oil
Neem oil is a vegetable oil pressed from the fruits and seeds of the neem , an evergreen tree which is endemic to the Indian subcontinent and has been introduced to many other areas in the tropics...
- Bog Myrtle
- IR3535
IR3535 is an insect repellent found in Avon Products Skin So Soft line of topical insect repellents. Merck KGaA is the registered trademark owner of IR3535 in the United States. IR3535 is a synthetic insect repellent that is additionally classified as biopesticide by the EPA...
(3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester)
PermethrinPermethrin is a common synthetic chemical, widely used as an insecticide, acaricide, and insect repellent. It belongs to the family of synthetic chemicals called pyrethroids and functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation. It is not known to...
is different in that it is actually a contact
insecticideAn insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
.
Repellent effectiveness
Synthetic repellents tend to be more effective and/or longer lasting than "natural" repellents. In comparative studies,
IR3535IR3535 is an insect repellent found in Avon Products Skin So Soft line of topical insect repellents. Merck KGaA is the registered trademark owner of IR3535 in the United States. IR3535 is a synthetic insect repellent that is additionally classified as biopesticide by the EPA...
was as effective or better than
DEETN,N-Diethyl-meta-toluamide, abbreviated DEET, is a slightly yellow oil. It is the most common active ingredient in insect repellents...
in protection against mosquitoes. However, some plant-based repellents may provide effective relief as well.
Essential oilAn essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile oils, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove...
repellents can be short-lived in their effectiveness, since essential oils can evaporate completely.
A test of various insect repellents by an independent consumer organization found that repellents containing DEET or picaridin 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.
For protection against mosquitos, the U.S. Centers for Disease Control issued a statement in May 2008 recommending equally DEET, picaridin, oil of lemon eucalyptus and
IR3535IR3535 is an insect repellent found in Avon Products Skin So Soft line of topical insect repellents. Merck KGaA is the registered trademark owner of IR3535 in the United States. IR3535 is a synthetic insect repellent that is additionally classified as biopesticide by the EPA...
for skin. Permethrin is recommended 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
Aedes aegyptiThe yellow fever mosquito, Aedes aegypti is a mosquito that can spread the dengue fever, Chikungunya and yellow fever viruses, and other diseases. The mosquito can be recognized by white markings on legs and a marking in the form of a lyre on the thorax...
, but requires reapplication after 30 to 60 minutes.
Repellent safety
Regarding
safetySafety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...
with insect repellent use on children and pregnant women:
- Children may be at greater risk for adverse reactions to repellents, in part, because their exposure may be greater.
- Keep repellents out of the reach of children.
- Do not allow children to apply repellents to themselves.
- Use only small amounts of repellent on children.
- Do not apply repellents to the hands of young children because this may result in accidental eye contact or ingestion.
- Try to reduce the use of repellents by dressing children in long sleeves and long pants tucked into boots or socks whenever possible. Use netting over strollers, playpens, etc.
- As with chemical exposures in general, pregnant women should take care to avoid exposures to repellents when practical, as the fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
may be vulnerable.
Regardless of which repellent product used, it is recommended to read the
labelA label is a piece of paper, polymer, cloth, metal, or other material affixed to a container or article, on which is printed a legend, information concerning the product, addresses, etc. A label may also be printed directly on the container or article....
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 (EPA) reported 14 to 46 cases of potential DEET associated seizures, including 4 deaths. The EPA states: "... it does appear that some cases are likely related to DEET
toxicityToxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
," 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 UniversityCornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
states that, "
Everglades National ParkEverglades National Park is a national park in the U.S. state of Florida that protects the southern 25 percent of the original Everglades. It is the largest subtropical wilderness in the United States, and is visited on average by one million people each year. It is the third-largest...
employees having extensive DEET exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers".
The EPA states that citronella oil shows little or no
toxicityToxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
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-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...
in certain individuals. Canadian regulatory authorities concern with citronella based repellents is primarily based on data-gaps in
toxicologyToxicology is a branch of biology, chemistry, and medicine concerned with the study of the adverse effects of chemicals on living organisms...
, 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),
IR3535IR3535 is an insect repellent found in Avon Products Skin So Soft line of topical insect repellents. Merck KGaA is the registered trademark owner of IR3535 in the United States. IR3535 is a synthetic insect repellent that is additionally classified as biopesticide by the EPA...
(3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester) and Citriodiol (
p-menthane-3,8-diolp-Menthane-3,8-diol, also known as para-menthane-3,8-diol, PMD, or Menthoglycol, is an active ingredient used in insect repellents. It smells similar to menthol and acts as a coolant. PMD is found in very small quantities in the essential oil within leaves of the Eucalyptus citriodora tree...
) 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; this does not preclude them from being sold for other purposes, as long as the label does not indicate they are a biocide (insect repellent).
Insect repellents from natural sources
There are many preparations from naturally occurring sources that are repellent to certain insects. Some of these act as insecticides while others are only repellent.
- Achillea
Achillea is a genus of about 85 flowering plants, in the family Asteraceae, commonly referred to as yarrow. They occur in Europe and temperate areas of Asia. A few grow in North America. These plants typically have frilly, hairy, aromatic leaves....
alpina (mosquitos)
- alpha-terpinene
The terpinenes are three isomeric hydrocarbons that are classified as terpenes. They each have the same molecular formula and carbon framework, but they differ in the position of carbon-carbon double bonds. α-Terpinene has been isolated from cardamom and marjoram oils, and from other natural...
(mosquitos)
- Basil
Basil, or Sweet Basil, is a common name for the culinary herb Ocimum basilicum , of the family Lamiaceae , sometimes known as Saint Joseph's Wort in some English-speaking countries....
- Sweet Basil (Ocimum basilicum)
- Callicarpa americana
American Beautyberry is an open-habit, native shrub of the Southern United States which is often grown as an ornamental in gardens and yards...
(BeautyberryBeautyberry is a genus of shrubs and small trees in the family Verbenaceae; between 40-150 species are accepted by different botanists. They are native to east and southeast Asia , Australia, southeast North America and Central America.-Growth:The temperate species are deciduous, the tropical...
)
- Camphor
Camphor is a waxy, white or transparent solid with a strong, aromatic odor. It is a terpenoid with the chemical formula C10H16O. It is found in wood of the camphor laurel , a large evergreen tree found in Asia and also of Dryobalanops aromatica, a giant of the Bornean forests...
(moths)
- Carvacrol
Carvacrol, or cymophenol, C6H3CH3, is a monoterpenoid phenol. It has a characteristic pungent, warm odor of oregano and a pizza-like taste.- Natural occurrence :...
(mosquitos)
- Castor oil
Castor oil is a vegetable oil obtained from the castor bean . Castor oil is a colorless to very pale yellow liquid with mild or no odor or taste. Its boiling point is and its density is 961 kg/m3...
(Ricinus communis) (mosquitos)
- Catnip oil (Nepeta species) (nepetalactone
Nepetalactone is an organic compound, first isolated from the plant catnip , which acts as a cat attractant. Nepetalactone is bicyclic terpenoid, i.e., it is a ten-carbon compound derived from isoprene with two fused rings, a cyclopentane and a lactone. The structure and the effects of the compound...
against mosquitos)
- Cedar oil
Cedar oil, also known as cedarwood oil, is an essential oil derived from the foliage, and sometimes the wood and roots, of various types of conifers, most in the pine or cypress botanical families...
(mosquitos, moths)
- Celery
Apium graveolens is a plant species in the family Apiaceae commonly known as celery or celeriac , depending on whether the petioles or roots are eaten: celery refers to the former and celeriac to the latter. Apium graveolens grows to 1 m tall...
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 trees from the genus Cinnamomum that is used in both sweet and savoury foods...
(leaf oil kills mosquito larvae)
- Citronella oil
Citronella oil is one of the essential oils obtained from the leaves and stems of different species of Cymbopogon. The oil is used extensively as a source of perfumery chemicals such as citronellal, citronellol and geraniol...
(repels mosquitos)
- Oil of cloves
Oil of cloves, also known as clove oil, is an essential oil from the clove plant, Syzygium aromaticum.* CAS number: 8000-34-8It is a natural analgaesic and antiseptic used primarily in dentistry for its main ingredient eugenol...
(mosquitos)
- Eucalyptus oil
Eucalyptus oil is the generic name for distilled oil from the leaf of Eucalyptus, a genus of the plant family Myrtaceae native to Australia and cultivated worldwide. Eucalyptus oil has a history of wide application, as a pharmaceutical, antiseptic, repellent, flavouring, fragrance and industrial uses...
(70%+ eucalyptolEucalyptol is a natural organic compound which is a colorless liquid. It is a cyclic ether and a monoterpenoid.Eucalyptol is also known by a variety of synonyms: 1,8-cineol, 1,8-cineole, limonene oxide, cajeputol, 1,8-epoxy-p-menthane, 1,8-oxido-p-menthane, eucalyptol, eucalyptole,...
), (cineol is a synonym), mosquitos, flies, dust mites)
- Fennel
Fennel is a plant species in the genus Foeniculum . It is a member of the family Apiaceae . It is a hardy, perennial, umbelliferous herb, with yellow flowers and feathery leaves...
oil (Foeniculum vulgare) (mosquitos)
- Garlic
Allium sativum, commonly known as garlic, is a species in the onion genus, Allium. Its close relatives include the onion, shallot, leek, chive, and rakkyo. Dating back over 6,000 years, garlic is native to central Asia, and has long been a staple in the Mediterranean region, as well as a frequent...
(Allium sativum) (rice weevil, wheat flour beetle)
- Geranium oil (also known as Pelargonium graveolens
Pelargonium graveolens is a species in the Pelargonium genus, which is indigenous to various parts of southern Africa, and in particular South Africa. It is often called geranium as it falls within the plant family Geraniaceae, although more correctly, it is referred to as Pelargonium. This...
)
- Lavender
The lavenders are a genus of 39 species of flowering plants in the mint family, Lamiaceae. An Old World genus, distributed from Macaronesia across Africa, the Mediterranean, South-West Asia, Arabia, Western Iran and South-East India...
(repels insects)
- Lemon eucalyptus (Corymbia citriodora) essential oil and its active ingredient p-menthane-3,8-diol
p-Menthane-3,8-diol, also known as para-menthane-3,8-diol, PMD, or Menthoglycol, is an active ingredient used in insect repellents. It smells similar to menthol and acts as a coolant. PMD is found in very small quantities in the essential oil within leaves of the Eucalyptus citriodora tree...
(PMD)
- Lemongrass oil (Cymbopogon species) (mosquitos)
- East-Indian Lemon Grass (Cymbopogon flexuosus
Cymbopogon flexuosus also called Cochin Grass or Malabar Grass Cymbopogon flexuosus also called Cochin Grass or Malabar Grass Cymbopogon flexuosus also called Cochin Grass or Malabar Grass (Malayalam: ഇഞ്ചിപ്പുല്ല്(inchippullu)is a perennial grass native to India, Sri Lanka, Burma, and Thailand. It...
)
- Marigolds (Tagetes species)
- Marjoram
Marjoram is a somewhat cold-sensitive perennial herb or undershrub with sweet pine and citrus flavours...
(Spider mites Tetranychus urticaeTetranychus urticae is one of many species of plant-feeding mites found in dry environments across the world, and generally considered a pest. It is the most widely known member of the family Tetranychidae or spider mites...
and Eutetranychus orientalis)
- Neem oil
Neem oil is a vegetable oil pressed from the fruits and seeds of the neem , an evergreen tree which is endemic to the Indian subcontinent and has been introduced to many other areas in the tropics...
(Azadirachta indica) (Repels or kills mosquitos, their larvae and a plethora of other insects including those in agriculture)
- Oleic acid
Oleic acid is a monounsaturated omega-9 fatty acid found in various animal and vegetable fats. It has the formula CH37CH=CH7COOH. It is an odorless, colourless oil, although commercial samples may be yellowish. The trans isomer of oleic acid is called elaidic acid...
, repels beeBees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
s and antAnts are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s by simulating the "Smell of death" produced by their decomposing corpses. It is a 400 millions years old natural mechanisms helping to sanitise the hives or to escape predators
- Pennyroyal
Pennyroyal refers to two plants in the mint family, Lamiaceae. For the American species, see American pennyroyal. The European pennyroyal, Mentha pulegium, , is a plant in the mint genus, within the family Lamiaceae. Crushed Pennyroyal leaves exhibit a very strong fragrance similar to spearmint...
(Mentha pulegium) (mosquitos, fleas), but very toxic to pets.
- Peppermint
Peppermint is a hybrid mint, a cross between the watermint and spearmint . The plant, indigenous to Europe, is now widespread in cultivation throughout all regions of the world...
(Mentha x piperita) (mosquitos)
- Pyrethrum
Pyrethrum refers to several Old World plants of the genus Chrysanthemum which are cultivated as ornamentals for their showy flower heads. Pyrethrum is also the name of a natural insecticide made from the dried flower heads of C. cinerariifolium and C...
(from Chrysanthemum species, particularly C. cinerariifolium and C. coccineum)
- Rosemary
Rosemary, , is a woody, perennial herb with fragrant, evergreen, needle-like leaves and white, pink, purple or blue flowers, native to the Mediterranean region. It is a member of the mint family Lamiaceae, which includes many other herbs, and is one of two species in the genus Rosmarinus...
(Rosmarinus officinalis) (mosquitos)
- Spanish Flag (Lantana camara
Lantana camara, also known as Spanish Flag or West Indian Lantana, is a species of flowering plant in the verbena family, Verbenaceae, that is native to the American tropics. It has been introduced into other parts of the world as an ornamental plant and is considered an invasive species in many...
) (against Tea Mosquito Bug, Helopeltis theivora)
- Tea tree oil
Tea tree oil, or melaleuca oil, is a pale yellow colour to nearly clear essential oil with a fresh camphoraceous odor. It is taken from the leaves of the Melaleuca alternifolia, which is native to the northeast coast of New South Wales, Australia...
- Thyme
Thyme is a culinary and medicinal herb of the genus Thymus.-History:Ancient Egyptians used thyme for embalming. The ancient Greeks used it in their baths and burnt it as incense in their temples, believing it was a source of courage...
(Thymus species) (mosquitos)
- Yellow Nightshade (Solanum villosum), berry juice (against Stegomyia aegypti mosquitos)
- Andrographis paniculata
Andrographis paniculata is a herbaceous plant in the family Acanthaceae, native to India and Sri Lanka.It is widely cultivated in Southern and Southeastern Asia, where it is used to treat infections and some diseases, often being used before antibiotics were created...
extracts(mosquito)
Inactive substances – carriers
In 2002, the
New England Journal of Medicine published an article that found products containing
essential oilAn essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile oils, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove...
s such as catnip or geranium oil, when combined with a suitable carrier oil such as soybean, have been found to be effective as natural repellents. This was based on testing done by Johns Hopkins and Cornell Universities. Other commercial products offered for household mosquito "control" include small electrical mats, mosquito repellent vapor, DEET-impregnated wrist bands, and mosquito coils containing a form of the chemical
allethrinThe allethrins are a pair of related synthetic compounds used in insecticides. They are synthetic pyrethroids, a synthetic form of a chemical found naturally in the chrysanthemum flower. They were first synthesized in the United States by Milton S. Schechter in 1949...
. Mosquito-repellent candles containing citronella oil are sold widely in the U.S. These have been used with mixed reports of success and failure.
Less effective methods
Some old studies suggested that the ingestion of large doses of thiamin could be effective as an
oralThe mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
insect repellent against mosquito bites. However, there is now conclusive evidence that thiamin has no efficacy against mosquito bites.
Some claim that plants like wormwood or sagewort,
lemon balmLemon balm , not to be confused with bee balm, Monarda species, is a perennial herb in the mint family Lamiaceae, native to southern Europe and the Mediterranean region....
, lemon grass,
lemon thymeThyme is a culinary and medicinal herb of the genus Thymus.-History:Ancient Egyptians used thyme for embalming. The ancient Greeks used it in their baths and burnt it as incense in their temples, believing it was a source of courage...
and the
mosquito plant (Pelargonium)Pelargonium is a genus of flowering plants which includes about 200 species of perennials, succulents, and shrubs, commonly known as scented geraniums or storksbills. Confusingly, Geranium is the correct botanical name of a separate genus of related plants often called Cranesbills. Both Geranium...
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 controlMosquito control manages the population of mosquitoes to reduce their damage to human health, economies, and enjoyment. Mosquito control is a vital public-health practice throughout the world and especially in the tropics because mosquitoes spread many diseases, such as malaria.Mosquito-control...
, such as the assertion that vitamin B, in particular B
1 (
thiamineThiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...
),
garlicAllium sativum, commonly known as garlic, is a species in the onion genus, Allium. Its close relatives include the onion, shallot, leek, chive, and rakkyo. Dating back over 6,000 years, garlic is native to central Asia, and has long been a staple in the Mediterranean region, as well as a frequent...
,
ultrasonicUltrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
devices or
incenseIncense is composed of aromatic biotic materials, which release fragrant smoke when burned. The term "incense" refers to the substance itself, rather than to the odor that it produces. It is used in religious ceremonies, ritual purification, aromatherapy, meditation, for creating a mood, and for...
can be used to repel or control mosquitoes. Moreover, some manufacturers of "mosquito repelling" ultrasonic devices have been found to be fraudulent, and their devices were deemed "useless" in tests by the UK Consumer magazine
Which?Which? is a product-testing and consumer campaigning charity with a magazine, website and various other services run by Which? Ltd ....
, and according to a review of scientific studies.
External links