Is Lavender A Mosquito Repellant? Important factors to Note

Mosquitoes can leave you crazy-eyed and twitching as your frantically slap at the annoying creatures. However, not everyone feels comfortable walking around in a cloud of chemical deterrents. For those who neither wish to live in a haze of itchiness nor bear the unappealing aroma of a science laboratory, Lavender offers a fragrant solution to those pesky insects!

So, is Lavender a mosquito repellant? Lavender solutions with 10% linalool (more than 65% (S)(+) linalool) are the most effective at repelling mosquitos. Linalool is more effective than citronella and Transfluthrin but less effective than geraniol. Indoor lavender diffusers have a 93% repellence rate.

Mosquitos are not just a harmless irritation; these blood-sucking flyers are vectors of Malaria, Dengue fever, Chikungunya, West Nile, and Zika virus. Each year, millions of people are infected with mosquito-transmitted diseases costing many people their lives. Finding a cost-effective mosquito-repellent is not simply an idle question of comfort but a life-saving measure.

How Effective Are Lavender Mosquito Repellents?

Mosquito repellant

Many of our modern chemicals and pharmaceuticals are derived from plant-based origins. However, there remains a certain stigma surrounding the efficacy of natural remedies.

The apathetic regard for the potency of herbal tinctures has caused them to be relocated to the realm of alternative medicine, i.e., unscientific and ineffective. Despite this commonly perpetuated fallacy, the past two decades have witnessed a significant increase in interest amongst the scientific community regarding the efficacy of plant-derived solutions.

One such remedy that has received increasing interest is the ability of plants to repel disease-carrying mosquitos. When studying mosquito repellents, three categories need to be considered:

  1. Topical repellents which are applied directly to the skin
  2. Airborne spatial repellents
  3. Lethal versus non-lethal repellents

How Effective Are Topical Lavender Mosquito Repellents?

Most topical mosquito repellents work by evaporation. The skin’s warmth causes the liquid or semi-liquid to evaporate and confuse the mosquito’s ability to find a viable food source, i.e., your blood!

While Lavender is often used to treat skin conditions, in its undiluted form, it can cause skin irritation and localized toxicity. This low-level toxicity is why most herbalists and massage therapists dilute the pure lavender essential oil with a carrier oil, e.g., avocado, coconut, or jojoba oil.

While dilution of the lavender oil is essential for your skin’s safety, it also dilutes the volatile chemicals of lavender essential oil. It is these chemicals that are responsible for repelling mosquitos.

Topically applied lavender mosquito repellents have a low to moderate efficacy due to the dilution of the essential oil with carrier oils.

How Effective Are Spatial Lavender Mosquito Repellents?

The active component of lavender essential oils, linalool, was investigated as a spatial repellent in 2009 and 2019 studies.

Efficacy Of Botanical Repellents: Geraniol, Linalool, And Citronella

The 2009 study investigated the mosquito repellent efficacy of three naturally occurring aromatic compounds, citronella (citronella plant), linalool (lavender plant), and geraniol (geranium plant), in both open and closed spaces.

The mosquito species studied was Aedes aegypti. The botanical repellents were released into the environment via 88g candles containing 5% active ingredient and air diffusers with 20g of a 100% active ingredient.

Read more: Is Lavender A Good Indoor Plant? Important Details to Know

The repellence rate for female Aedes aegypti indoors:

  1. Citronella candles were 14%, and the diffusers were 68%
  2. Geraniol candles were 50%, and the diffusers were 97%
  3. No linalool candles were included in the study, but the diffuser’s indoor repellence rate was 93%

The repellence rate for female Aedes aegypti outdoors:

  1. Citronella diffusers were 22% when placed 6 meters from the mosquito trap; once the distance was reduced to 3 meters, the repellence increased to 65.6%
  2. Geraniol diffusers were 75% when placed 6 meters from the mosquito trap; once the distance was reduced to 3 meters, the repellence increased to 95.5%
  3. Linalool diffusers were 58% when placed 6 meters from the mosquito trap; once the distance was reduced to 3 meters, the repellence increased to 88.4%

Efficacy Of Transfluthrin Versus Linalool

A 2019 study investigated the effects of Transfluthrin versus linalool. Transfluthrin is a common pyrethroid-based insecticide that is fast-acting with low persistency.

Despite being widely available as a commercial mosquito repellent, Transfluthrin can cause toxic pathophysiology in the liver, trachea, lungs, kidneys. If released into the environmental water source, Transfluthrin will cause catastrophic fatalities amongst aquatic life. As such, scientists are investigating linalool as an effective alternative to Transfluthrin.

The spatial repellent properties of Transfluthrin and linalool were investigated concerning Aedes aegypti and Aedes albopictus mosquito species.

The repellence rate for Aedes aegypti:

  1. Transfluthrin, 0.001% solution, was approximately 37%, with a variation of 4.33% between trials
  2. Linalool 10% solution was approximately 78% with a variation of 3.9% between trails

The repellence rate for Aedes albopictus:

  1. Transfluthrin, 0.001% solution, was approximately 45%, with a variation of 3.78% between trials.
  2. Linalool 1% and 10% solution was approximately 56% with a variation of 7% for 1% solutions and 6.46% for 10% solutions between trails

The Take-Home Message Regarding Lavender’s Spatial Repellence

Linalool is more effective as spatial repellence than citronella essential oil and the commercially available Transfluthrin; however, it is less effective than geraniol.

The greater the concentration of the airborne linalool either by distance or solution used, the more potent its effects on repelling female mosquitos.

Users Also Read: Are Lavender Leaves Edible?

Is Lavender Repellents Lethal To Mosquitos?

The high-pitched whine of a mosquito can drive a person to murder; however, these murderous urges will remain unfulfilled when using a lavender-based mosquito repellent.

Unlike, Transfluthrin which has a 70% to 100% mosquito mortality rate within 24 hours of exposure, Lavender-based repellents do not harm mosquitos in any way.

While this may seem like a dismal result for those haunted by real and imagined mosquito bites, but it is a promising result for the use of linalool as a biosafe mosquito repellent. The use of this volatile compound is unlikely to cause damage to the surrounding wildlife if it accidentally contaminates the local soil or water supply!

How Do Lavender Plants Repel Mosquitos?

Numerous studies have proven the effectiveness of linalool as a mosquito repellent. Still, until recently, scientists have been unable to explain WHY linalool acts as a repellent to some insects and an attractant to others.

All mosquito repellents work on one of three principles:

Mosquito Repellant
  1. Masking human CO2 emissions, thus preventing the mosquito female from detecting a food source
  2. Repelling mosquitos through aversive odors that cause them to leave a viable host alone
  3. Attractants that lure the mosquito away from a possible host and towards a more attractive scent

Chemical Signalling And Behavioural Alteration

Insects use chemoreceptors to detect environmental cues that guide them to the best feeding, egg-laying, and resting sites. Mosquitos are equipped with three different types of chemoreceptors:

  1. Odorant receptors
  2. Gustatory receptors
  3. Ionotropic glutamate receptors

 A 2019 study investigated the receptor-ligand interactions of olfactory receptor 29 and the environmental ligand, linalool. The olfactory receptor 29 is predominantly expressed in the labellar lobes of both mosquito sexes. It is used in short-range chemical detection, which influences the behavioral responses of male and female mosquitos.

Linalool is a volatile monoterpene compound found in flowering plants, where it exists as two stereoisomers (variations) (R)(-) linalool and (S)(+) linalool. Even humans can detect the difference between the two stereoisomers, as (R)(-) linalool features the characteristic lavender scent while (S)(+) linalool smells like coriander.

Both linalool stereoisomers are detected at olfactory receptor 29, where they cause neuronal activation. The chemical signal is transmuted into a nervous impulse which the blood-feeding mosquito female interprets as an unpleasant, aversive stimulant.

Interestingly, nectar-feeding mosquito species are ATTRACTED to linalool. This study produced unique insights into the behavioral adaptations that mosquitos show in response to linalool stereoisomers.

In blood-dependent mosquito females, linalool is an aversive repellent causing them to fly away from viable hosts. However, in nectar-feeding mosquitos, linalool is an attractant, with different species showing distinct preferences for the two stereoisomers.

Linalool extracts containing a minimum of 65% (s)(+) linalool exhibited the most significant receptor-ligand activation and repellence efficacy.

Commercial Mosquito Repellents Containing Lavender

Lavender oil

Artizen Lavender produces a 100% pure therapeutic grade lavender, which can be used in a diffuser to create a calm, mosquito-free room. This diffuser set comes with 10 different essential oils, including Lavender.

Victoria’s Lavender, All Natural Bug Spray, is 100% DEET-free and features a mixture of lavender essential oils and aloe vera. It is safe for topical use but can also be used as an airborne deterrent. This brand will not only keep you mosquito-free, but it also works to repel flies and ticks!

Homemade Mosquito Repellents Containing Lavender

While diffusers are the most effective means of using Lavender as a mosquito repellent, carrying a diffuser with you is not always feasible. You’re hardly going to enjoy your hike if you are lugging along a diffuser and power supply!

In these cases, a homemade topical lavender application may be just the thing. When making a topical application from essential oils, it is crucial to remember that you should dilute every 20 drops of essential oil used with 2 tablespoons of carrier oils.

The best carrier oils are almond, coconut, jojoba, argan, and avocado. The most effective homemade remedies contain equal parts lavender and geranium essential oils; however, if you don’t like the smell of geranium, you can make a lavender-mint mixture or just pure Lavender.

For maximum effect, apply the topical spray every 30 to 60 minutes.

Conclusion: Is Lavender A Mosquito Repellant?

Lavender contains the compound linalool, which repels blood-feeding mosquitos when detected by their olfactory receptors. The higher the concentration of linalool, the more effective it is.

Sources

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225637

https://www.cdc.gov/niosh/topics/outdoor/mosquito-borne/default.html

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1948-7134.2009.00002.x

https://onlinelibrary.wiley.com/doi/full/10.1111/jvec.12332

https://www.medicalnewstoday.com/articles/lavender-oil-for-skin#how-to-use

https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-014-0550-2

https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-014-0550-2

https://link.springer.com/article/10.1007/s00441-020-03407-2