Herbs and Botanicals

Hygiene and Essential Oils as Natural Bug Repellents

Natural approaches to mosquito repellents

Mosquito resting on a reflective table
Credits: "Pixabay"
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DEET, or N,N-diethyl-m-toluamide, is the major active ingredient in most commercially available insect repellents on the market. Although considered safe by the FDA and EPA, DEET has many precautions associated with it and a less than favorable history of toxicity during World War II.[1,2] DEET is also becoming less effective against mosquitos after their first exposure to the repellent.[3] All of which are great motivators for individuals to seek options for more natural repellents.

Research shows that many species of mosquitos have adapted to be attracted to human body odor over the scents of other animals.[4]  Our bodies produce a substance called, sulcatone, which mosquitos have developed an odorant receptor to detect.[4] It has also been speculated that odor caused by bacterial colonies on our skin, such as S. epidermidis and C. minutissimum, may contribute to insect detection and location of humans.[5-7] Cleansing the skin in areas of higher bacterial count, such as the feet and armpits, and the use of deodorants prior to outdoor activates and where mosquitos might be encountered could potentially decrease your interaction with them.[8] 

A quick internet search can produce hundreds of natural remedies for insect repellents, but not all of these are created equal. Essential oils in particular have gained popularity recently for their use as natural repellents. Why are these oils so “essential”? An essential oil is just concentrated oil extracted from a large volume of any plant material, most commonly, through steam distillation. These oils are volatile, meaning they evaporate and become aromatic. This characteristic is what gives them the ability to repel insects.[9]

 

Which Essential Oils Can be Used? 

Citronella

Popularized by its candle form, citronella from Cymbopogon nardus, is a strong insect repellent due to the active constituent citronellal.[9-11] One study found that adding vanillin, which is extracted from the vanilla bean, to citronella oil increases the duration of its effectiveness for up to eight hours.[10] Caution is needed while using citronella because direct use of the undiluted essential oil can cause a skin irritation.

Lemon eucalyptus

This plant’s oil has many volatile components, but the constituent found to have the best repellent activity is para-methane-3,8,-diol (PMD).[9,12] PMD has been shown to have DEET-like efficacy and has been endorsed by the CDC as providing “reasonably long-lasting protection” from disease carrying mosquitos.[11,12] As with all citrus family oils, lemon eucalyptus contains limonine, which causes a photo-dermatitis reaction when used topically.[9] Direct used of the unadulterated lemon eucalyptus oil should be avoided, especially during sun exposure.  

Other popular and effective essential oils include eucalyptus, patchouli, thyme, clove and lemongrass derived essential oils.[9,10,13] 

 

Use of Essential Oils

Due to the very potent nature of essential oils it is important to remember that concentrations of 100% are avoided for skin application. Use of a carrier oil such as coconut, almond, grapeseed, soybean, or rose hip are a great and necessary way to dilute essential oils.  Typical dilutions are no greater than 3% concentration (20 drops of essential oil in 1 ounce or 30 mL of carrier). It is smart to test a small area of skin to see if the dilution will cause an unwanted reaction. If there are questions about safety and toxicity an expert should be consulted.   

Other options include: 

  • Making a spray with an oil by adding a few drops to an ounce of water, mix well by shaking and diffuse using a spray bottle 
  • Crafting candles with the oils 
  • Use an essential oil diffuser to permeate the air

 

* This Website is for general skin beauty, wellness, and health information only. This Website is not to be used as a substitute for medical advice, diagnosis or treatment of any health condition or problem. The information provided on this Website should never be used to disregard, delay, or refuse treatment or advice from a physician or a qualified health provider.

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References

1.    Staff U. Insect Repellent Use and Safety in Children. 2016; http://www.fda.gov/drugs/emergencypreparedness/ucm085277.htm. . Accessed June 30, 2016.
2.    Staff U. DEET.  https://www.epa.gov/insect-repellents/deet. Accessed June 30, 2016.
3.    Stanczyk NM, Brookfield JF, Field LM, et al. Aedes aegypti mosquitoes exhibit decreased repellency by DEET following previous exposure. PLoS One.2013;8(2):e54438; PMID: 23437043.
4.    McBride CS, Baier F, Omondi AB, et al. Evolution of mosquito preference for humans linked to an odorant receptor. Nature.2014;515(7526):222-227; PMID: 25391959.
5.    Zhang X, Crippen TL, Coates CJ, et al. Effect of Quorum Sensing by Staphylococcus epidermidis on the Attraction Response of Female Adult Yellow Fever Mosquitoes, Aedes aegypti aegypti (Linnaeus) (Diptera: Culicidae), to a Blood-Feeding Source. PLoS One.2015;10(12):e0143950; PMID: 26674802.
6.    Verhulst NO, Qiu YT, Beijleveld H, et al. Composition of human skin microbiota affects attractiveness to malaria mosquitoes. PLoS One.2011;6(12):e28991; PMID: 22216154.
7.    Verhulst NO, Andriessen R, Groenhagen U, et al. Differential attraction of malaria mosquitoes to volatile blends produced by human skin bacteria. PLoS One.2010;5(12):e15829; PMID: 21209854.
8.    Verhulst NO, Weldegergis BT, Menger D, et al. Attractiveness of volatiles from different body parts to the malaria mosquito Anopheles coluzzii is affected by deodorant compounds. Sci Rep.2016;6:27141; PMID: 27251017.
9.    Maia MF, Moore SJ. Plant-based insect repellents: a review of their efficacy, development and testing. Malar J.2011;10 Suppl 1:S11; PMID: 21411012.
10.    Tawatsin A, Wratten SD, Scott RR, et al. Repellency of volatile oils from plants against three mosquito vectors. J Vector Ecol.2001;26(1):76-82; PMID: 11469188.
11.    Nasci RS WR, Brogdon WG. Protection Againts Mosquitoes, TIcks, and Other Arthropods. 2015; http://wwwnc.cdc.gov/travel/yellowbook/2016/the-pre-travel-consultation/protection-against-mosquitoes-ticks-other-arthropods. Accessed July 12, 2016.
12.    Carroll SP, Loye J. PMD, a registered botanical mosquito repellent with deet-like efficacy. J Am Mosq Control Assoc.2006;22(3):507-514; PMID: 17067054.
13.    Meng H, Li AY, Costa Junior LM, et al. Evaluation of DEET and eight essential oils for repellency against nymphs of the lone star tick, Amblyomma americanum (Acari: Ixodidae). Exp Appl Acarol.2016;68(2):241-249; PMID: 26590930.