The Anopheles albimanus mosquito transmits malaria, usually in sub-tropical and tropical locations.Image in the public domain
“The mosquito is the world’s ,” the female members of its 3,700 varieties causing dengue, malaria, and West Nile Virus, among other diseases, as reported by the Center for Disease Control’s (CDC) Global Health Center.
Other insect vectors include fleas infected with Yersinia pestis, the bacteria responsible for the bubonic plague that felled 25+ million Europeans during the (1346-135) of the Late Middle Ages and that, while rare, remains active today.
Biting flies and ticks are also insect vectors, with the latter infecting humans with babesiosis, ehrlichiosis, Lyme disease, and Rocky Mountain Spotted Fever. As stated on the John Hopkins Bloomberg School of Health website, the most common of the four is , whereby as many as half a million patients are diagnosed and treated each year in the United States.
In this article, we’ll discuss how certain colors are less attractive to insect vectors, especially mosquitos. We’ll also talk about bug-resistant finishes and puncture-proof textiles.
According to , Endowed Professor (Department of Biology) at the University of Washington, as quoted in a February 4, 2022, news release, “Mosquitoes appear to use odors to help them distinguish what is nearby, like a host to bite. When they smell specific compounds, like [carbon dioxide] from our breath, that scent stimulates the eyes to scan for specific colors and other visual patterns, which are associated with a potential host, and head to them.” Riffell was one of a team of scientists who investigated how the Aedes aegypti, or yellow fever mosquito, responded to color and co-author of the research results, which were released on the same date in Nature Communications.
As observed during the study, when exposed to a blue, green, or purple dot in a mini-chamber sprayed with carbon dioxide (CO2), overall, the yellow fever mosquito paid no attention to the spot at the bottom of the compartment. But when the dot was black, cyan (blue-green), orange, or red, the pigment found in all human skin, the test subject alighted for a closer look. Following a whiff of the gas, Aedes aegypti showed a preference for longer wavelengths in the visible spectrum. Please note that, as summarized in the team’s findings, mosquitos with changes in their deoxyribonucleic acid (DNA) sequences (mutations), related to smell or vision demonstrated less or no sensitivity to color, even when the trial chamber contained carbon dioxide.
After being exposed to carbon dioxide, Aedes aegypti appeared to prefer longer wavelengths in the visible spectrum.Image courtesy of Jeffrey Riffell, University of Washington
In response to a query about updates to the study, Riffell replied, “We have several papers coming out on the preferences of mosquitoes for certain colors. These studies build on our 2022 paper, where we showed that mosquitoes prefer dark colors,black and red. We now have evidence that mosquitoes (Aedes aegypti) prefer a specific color of blue. However, “Current work on the color preferences of ticks (Ixodes genus) has indicated that they do not have clear color preferences (white is equally preferred to brown and green). By contrast, there is work on kissing and bed bugs that show they prefer red and black (similar to mosquitoes).” While ticks have so far proved indifferent to the colors on the visible spectrum, the advises wearing light-colored garments outdoors as they allow for easier detection of .
Unlike bed bugs, kissing bugs, and mosquitos, “ticks [Ixodes genus] don’t have eyes,” a surprising fact shared by Thomas Mather, Director of the TickEncounter Resource Center and Professor of Public Health Entomology at The University of Rhode Island, which most likely accounts for their indifference to color. Those classified as Amblyomma and Dermacentor have eye-like components located of their backs that may function more like photoreceptors.
Permethrin, a synthetic insecticide, registered with the EPA (1979, 2006), is deadly to insect vectors but safe for humans if used appropriately.Image in the public domain.
Ticks are, however, extremely sensitive to (C21H20Cl2O3), a breakthrough synthetic insecticide discovered by chemist Michael Elliot and his colleagues at the Rothamsted Research Institution in the early 1970s, as described in his article, “:”
“At Rothamsted Experimental Station in 1972 [United Kingdom], an exceptionally valuable combination of properties was found in the esters (permethrin) of 3-phenoxybenzyl alcohol with the cis- and trans- dichlorovinyl acids (9,10,46,47) analogs of chrysanthemic acid with chlorine in place of methyl in the isobutenyl side chain. Not only was permethrin more active against many insect species than would have been predicted from experience with other esters of the acidic and alcoholic components, but it was also very much more stable in air and light than other potent pyrethroids&/aatccnews_2025-02b/8230;”
Adult deer or black-legged ticks (Ixodes scapularis) transmit Lyme disease.Image in the public domain
Permethrin is similar to , a combination of six chemicals derived from the seed cases of chrysanthemum flowers, used to repel mosquitos and treat lice in ancient Persia (southwestern Asia), beginning in the fifth century.
As described by Thomas Mather, permethrin attacks and penetrates the central nervous system of most insect vectors the same way—by interfering with their sodium channels and disrupting the function of neurons, resulting in muscle spasms and relatively quick death. To illustrate, Mather relayed the results of an informal experiment, whereby the participant wore a gardening glove treated with permethrin. Nymph-stage black-legged ticks that came in contact with the glove fell off, some within five seconds. Most were immobile after thirty seconds to three minutes and were dead when examined a few hours later. Ticks placed on untreated gloves remained motile and lively.
Permethrin, initially registered with the EPA in 1979, was approved in the early 1990s as a factory treatment and spray repellant for both consumer clothing and military uniforms. In January 2025, the ɫֱspoke with Rick Hemmerling, Executive Vice-President of Insect Shield LLC., founded in 2001, who explained how permethrin is applied to garments and textiles in a factory setting:
Garments treated with Insect Shield’s proprietary permethrin technology are available directly from the company. Additionally, customers can submit their own clothes for factory treatment. Image courtesy of Rick Hemmerlin Insect Shield LLC
“We use a proprietary end-of-line system (applied in finished garment form) that we have invented ourselves.We’ve also created a proprietary binder chemistry for applying permethrin so it can last seventy washings&/aatccnews_2025-02b/8230;or the expected lifetime of the garment (EPA-registered for seventy washes). The permethrin is bonded to the fabric at a ratio of 0.52% w/w.” As the binder chemistry and end-of-line system are exclusive to the company, Hemmerling was unable to elaborate any further.
When evaluating their fabrics for washability,“The only ɫֱtest [Insect Shield] uses is for wash durability: ɫֱTM135 in conjunction with gas chromatograph content testing. The EPA requires the weight/weight ratio to be tested by gas chromatography-mass spectrometry (GCMS). Effectiveness requirements are tested by a third-party petri-dish knock-down method, the EPA and World Health Organization (WHO) tube test for [the US], Europe, and other countries requesting that test method.”
ɫֱalso spoke with Melynda Perry, a textile chemist for the US Army since 2005, who serves on ɫֱRA49: Insect Resistant Test Methods. The committee is associated with one lab procedure, ɫֱLP3: Transfer of Free Permethrin from Textile Surfaces, and one test,ɫֱTM194: Anti-House Dust Mite Properties of Textiles under Long-Term Test Conditions.
Etofenprox is a pyrethroid-like, synthetic insect repellant used on US Army uniforms.Image in the public domain
As detailed by Perry, the USMilitaryuses permethrin, a synthetic pyrethroid, to treat their uniforms. Etofenprox, a, is alsoregistered with the EPAfor factory treatment ofuniforms. TheUS Army,US Air Force,and US Marinesall wear permethrin-factory treated uniforms to includesome of their flame-resistant garments, as indicated on the EPA-required labels sewn into the jackets and pants. Although permethrin is effective against a broad range of insect vectors, including ticks, the finish is primarilytested againstmosquitos. In a factory setting, it can be applied by way of a 1) “dip-and-nip” method, where the fabric is submerged in a bath and then passed through pressurerollers, or 2) affixed directly to the end item or garment.
Etofenprox is a pyrethroid-like, synthetic insect repellant used on US Army uniforms.Image in the public domain
Perry emphasized that the military’s use of insect-repellant fabrics makes for a unique situation, due to the need for compromise and trade-offs required when manufacturing military uniforms to achieve a balance between protection, durability, and comfort. For example, a breathable, lightweight garment, while comfortable to wear, may prove less protective against mosquito bites. Finishing and bite protection challenges also include, among other things, fabric construction and fiber blends. When addressing these challenges, Perry stressed the “importance of ensuring all requirements are met,” especially when finishing textiles and uniforms destined for a combat zone.
A subject matter expert who partners with , Mather addressed the safety of permethrin-infused fabrics. He noted that as long as users followed the directions on the product’s hang tag, for example, washing the garments separately, permethrin demonstrates low mammalian toxicity because it’s poorly absorbed by the skin. The results of a study he co-authored on the long-lasting permethrin-impregnated (LLPI) garments published in the Journal of Medical Entomology on December 27, 2021, indicated “that treated and unworn commercial LLPI clothing can provide >95% mortality to nymphal black-legged ticks exposed for three minutes, despite occasional batch-to-batch variability in the amount of permethrin retained on the clothing.” In the study, outdoor workers wearing factory-impregnated clothing significantly reduced tick bites by 65% in the first study year and by 50% in the second year when compared to workers wearing sham-treated clothing. Moreover, based on urine samples collected from twelve foresters from 2016-2017, “The median level of urinary permethrin metabolites from all study participants increased in concentration over baseline levels at both one month and three to four months after participants began wearing LLPI clothing; however, after one year of wearing LLPI clothing, levels of permethrin metabolites in urine samples decreased.”
To date, as noted by Mather, natural textile treatments have not proved very effective when it comes to killing ticks. And because they’re exempt from regulation, most have not been rigorously evaluated. Mather’s team tested some 20 commercially available and experimental products, mostly essential oils and soaps in small, controlled field studies and found most lacking significant efficacy. As of this writing, his lab is just beginning to assess the effectiveness of natural ingredients as tick repellents.
Three-dimensional model of a Nootkatone molecule. Image is in the public domain.
In addition to natural pyrethrum, one promising possibility is (C15H22O), approved by the EPA in August 2020 for use as a biopesticide. It can be extracted in small quantities from the bark and skin, respectively, of Alaskan yellow-cedars and grapefruits. To address this costly and unsustainable process, Evolva, a biotechnology company established in 2004 and headquartered in Reinach, Switzerland, developed that’s based on an “innovative yeast fermentation process and nearly identical to the chemical compound found in nature,” as stated on the company’s website. As of January 2025, the company’s registration application is awaiting approval from the EPA.
Alternatives to chemical and natural textile treatments include pants, shirts, and accessories, compression-fitting garments designed to be worn in tandem and protect wearers from insects that bite instead of sting. These include chiggers, microscopic, wingless mites; biting midges (no-see-ums), fast-moving ticks, and mosquitos. Composed of nylon and Lycra, the breathable, ultra-fine mesh fabric is best worn as a base layer, whereby form-fitting ankle and cuffs and targeted double layers at the elbows and knees effectively seal off the wearer and prevent biting insects from reaching the skin.
In &/aatccnews_2025-02b/8220;,&/aatccnews_2025-02b/8221; published in Insects magazine in 2021, Kun Luan, et al., from North Carolina State University (NCSU) summarized the results of a study based on a computational model of the yellow fever mosquito (Aedes aegypti), including the size of its antenna, head, and proboscis, along with its biting mechanism. In their conclusion, the authors stated, “Our model was verified throughin vitrobioassays, using woven fabrics, plastic spacer plates, and knitted and knitted spacer fabrics, which showed that the model could accurately predict bite-resistance of mechanical barriers&/aatccnews_2025-02b/8230;When compared with permethrin-treated fabric, our fabrics&/aatccnews_2025-02b/8230;had a higher bite-resistance with a predicted higher level of protection for exposed skin,” with the latter requiring additional research, as conducted by , a start-up affiliated with NCSU.
&/aatccnews_2025-02b/8220;The purpose of testing,&/aatccnews_2025-02b/8221; as noted byMelynda Perry, is “to achieve consistent and repeatable results whenfactory-treating.”Given that each year, mosquito-borne illnesses are responsible for more thanacross the globe, research and development of insect-resistant/protective textiles remains critical, as does following current protocols for avoiding the diseases caused by insect vectors. The US Military uses the Department of Defense (DoD) Insect Repellent system to protect the warfighter from insect-borne diseases, which includes:
In the civilian world protection can include wearing tightly knit compression-fitting apparel, loose clothes with an air gap between the body and the fabric, and/or permethrin-treated garments outdoors to make sure that mosquitos and ticks get the message: bug off.
ɫֱ the Author
, a freelance writer and graduate of the Fashion Institute of Technology’s textile design program (concentration in woven design), has more than ten years of experience in e-learning and information services.
A Lyme-disease survivor, she is passionate about the need for outdoor enthusiasts to remain informed about and protect themselves from insect vectors.
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