What Keeps Mosquitoes Away? Controls That Actually Work

This article has been updated from its original text.

Tackling bug-bites in the middle of the night may be one drawback of summer, but mosquitos are more than an annoyance in many parts of the world. Carrying diseases like malaria, dengue fever, and West Nile and Zika viruses, they account for more than one million deaths each year according to the World Health Organization. As climate change warms the planet and increases mosquito-friendly habitat worldwide, this number is expected to rise.

The seriousness of mosquito-borne diseases is the reason so much research has gone into keeping people safe from their bites. It’s also the reason so many products on the market claim to prevent you from becoming a mosquito’s next meal. But are these products effective?

Whether you’re trying to avoid a disrupted sleep or a risky disease, it’s worth spending your money on measures that work. Here’s what scientists are saying about the efficacy of mosquito control products. Here also are the most effective remedies that will keep mosquitoes at bay this summer.

The latest advances (don’t work)

There really is an app for everything. In the past few years, many developers have come out with smartphone applications that purport to repel mosquitoes. LG also unveiled a smartphone with built-in, mosquito-repelling technology. The only problem? They don’t work.

More accurately, there’s no scientific evidence to support the claims that the ultrasonic technology employed in mosquito-repelling devices actually keeps mosquitoes away. In fact, the opposite is true.

Many studies disprove the idea that ultrasonic technology repels mosquitoes. In one blinded, controlled study, scientists found no significant difference between a test area subject to an ultrasound device designed to repel mosquitoes and an area without the device. Another study demonstrated that electronic devices purporting to control mosquitoes with sound actually increased biting rates. So, are ultrasonic mosquito repellants effective? The science doesn’t yet say they are.

While researchers conducted these studies before the release of the latest smartphone apps, mosquito-control apps on the market today use the same technology as the ultrasonic mosquito repellent devices tested. The conclusion is that this technology didn’t work in other devices, so why should it work in smartphones?

The same goes for the ultrasonic wearable patches available from a variety of manufacturers. A 2017 study published in the Journal of Insect Science tested five wearable devices, finding that only one had any results. That one used a nebulizer containing metofluthrin, an ingredient known to repel mosquitoes when used as a fogger to emit a vapor around its wearer.

Of ultrasonic technology, the study concluded: “We’re not aware of any scientific study showing that mosquitoes can be repelled by sound waves, and therefore we consider these devices as the modern equivalent of snake oil.”

Photo by Bima Wahyu on Unsplash

What really keeps mosquitoes away?

Today’s scientists generally agree that the best mosquito controls include a combination of repellents applied to skin or clothing and physical barriers that prevent mosquitoes from reaching you in the first place. But not all products are created equally. Here’s a look at the most effective controls backed up by science.

Repellents

Since the US Department of Agriculture developed DEET in 1944, the synthetic chemical has been a mainstay of bug repellents. Short for N, N-diethyl-3-methylbenzamide, DEET works by activating the olfactory receptors in mosquitoes, effectively repelling them because they dislike its smell. Unfortunately DEET can irritate mucous membranes and cause skin reactions, burning eyes, breathing difficulties, and headaches in some people.

Both the EPA and the CDC have determined DEET to be safe, but recommend concentrations of 30% or less on children. (The American Academy of Pediatrics recommends 10%). Never apply DEET to rubber, vinyl, plastic, and spandex because it may dissolve these fibers.

Although scientists and manufacturers have done many trials to find a DEET equivalent, only a few plant-based source have shown promise.

• Oil of lemon eucalyptus (OLE) containing p-menthane-3, 8-diol (PMD) performed equally well as DEET in the Journal of Insect Science study quoted above. It also worked for the same length of time as DEET products. Study authors concluded that, “DEET and PMD [are] the most effective and longest lasting mosquito repellents currently available.” PMD is found in products containing C. Citriodora (oil of lemon eucalyptus) and the tradenames Citrosynthol, Citrepel and Citriodiol. It is also effective against ticks.
• Neem oil has also been proven effective by one study conducted in the tribal forested villages of Mandla, India. Derived from the neem tree (Azadirachta indica) native to the Indian subcontinent, Neem oil mixed with coconut oil and applied directly to the skin reduced mosquito bites by up to 91%. When added to kerosene and oil lamps along with other fuel, neem oil is also known to reduce mosquito presence.
• Picaridin is another synthetic ingredient proven effective against mosquitoes. Developed in Europe in the late 1990s, picaridin became available to American consumers in 2005. Studies show it must make up at least 20% of the solution to be effective. While it’s generally considered to be a safe alternative to DEET (without any of that chemical’s plastic-dissolving traits), picaridin hasn’t been as heavily tested.
• A kid’s version of Herbal Armor also fared well in the Insect Science study. Containing a mix of essential oils including citronella, cedar, lemongrass, and peppermint, it performed just as well as a 40% DEET solution and better than a 10% picaridin solution.

Barriers

When cases of dengue fever began cropping up in Key West, Florida, local officials asked residents to protect themselves by dressing in long sleeves and long pants at dusk and dawn, when mosquitoes were more prevalent and more likely to bite. Treating clothing with repellent can help as well. Just be aware that permethrin, a common ingredient used to treat clothing for mosquitoes, is a known carcinogen if consumed and has been linked to Parkinson’s disease. Permethrin also acts like an insecticide instead of a deterrent, so mosquitoes may still bite you through a permethrin-treated garment and not die until afterwards. Permethrin-treated clothing is generally considered safe and is now available from major outdoor retailers.

When camping in areas with healthy mosquito populations, nothing beats a physical barrier like bug jackets with enclosed hoods and mosquito shelters for sleeping or eating. We especially like Onsight insecticide-free mosquito shelters because they’re made from 60-100% recycled materials.

Aerosols

Recently products have entered the market that are effective at warding off mosquitoes using scents or aerosols emitted into the air. One common ingredient used in these products is the insecticide allethrin. The Thermacell uses butane gas to heat pads soaked with allethrin. These pads emit an aura that attacks the nervous system of mosquitoes. Allethrin is effective at warding off mosquitoes in targeted outdoor areas. Scientists recommend against using the product in enclosed spaces. The product is also known to be toxic to bees, cats and fish, so caution should be used when choosing anything containing this ingredient.

Other ways to control mosquitoes

Get rid of mosquito habitat

Eliminate standing water such as puddles, stagnant ponds, and uncirculated birdbaths to prevent mosquitoes from reproducing and lower mosquito populations in your neighborhood. In places where you can’t remove standing water, try adding mosquito dunks. These unique products use a naturally occurring bacterium toxic only to mosquito larvae. They’ll kill in a few hours and keep working for 30 days.

Light a candle

While citronella candles are generally not effective outdoors, they can be effective when used inside, in small spaces. Other candles containing essential oils may help fool mosquitoes thanks to their strong scents, though more studies are needed to determine their effectiveness.

Turn on the fan

Oscillating fans can help remove the carbon dioxide breathed out by people and pets, which attracts bugs. This is another solution for small indoor spaces.

Plug in electronic bug killers

How does electric mosquito repellant work? Not to be confused with ultrasonic bug killers, these devices attract mosquitoes and other bugs using UV light and octenol lures. Bugs fly directly into an electrified grid and die quickly. Electronic bug killers are designed to work in areas of up to one and a half acres and should be plugged in 25 feet away from areas of high human activity—between you and your most likely bug source. Power using an extension cord and replace UV bulbs once per year. If you are targeting mosquitoes, be sure to use the octenol lure or you may end up killing beneficial insects instead.

Add some bird and bat houses

While installing biological controls won’t be your first line of defense against mosquitoes, adding bird and bat houses to your backyard is one way to decrease the mosquito population. Bats, dragonflies, and birds like Purple martins, all do their share of the work when hunting for food. However, keep in mind that they eat a small fraction of the mosquitoes when other prey is available, so using other controls at the same time is important. For more details on how to use bats to help control mosquitoes, read our article, How to use Bats for Natural, Non-Toxic Mosquito Control.

Mosquito control myths

The following tales about things that attract (or repel) mosquitoes just aren’t true.

1. Floral scents attract them (nope). Researchers involved in one of the studies above looked at floral scents as possible mosquito magnets. What did they find? There was no attraction. In fact, some floral scents had short-term repelling effects thanks to their ability to mask our human scent, though not enough to make them your go-to mosquito repellent. Thankfully, you don’t have to stop wearing that floral scented perfume—unless you really want to.
2. Consuming vitamin B1 will make you less desirable to mosquitoes (sorry—not true). There’s no proof that vitamin B1 (or any other vitamin) is a good systemic mosquito repellent.
3. Eating bananas make you into mosquito bait (no again). While bananas contain octenol (a mosquito attractant), there’s no evidence that eating them will somehow make you exude this mosquito-friendly substance, drawing them to you like flies to honey. So go ahead and chow down: mosquitoes won’t care.
4. Mosquitoes don’t like some people (partly true). A mosquito chooses its victims based on a few factors. The first is visual stimulus, and there’s some evidence showing that dark colors could make you stand out and be more attractive to mosquitoes. The next, and probably most important factor, is the amount of carbon dioxide you breathe out with each breath. People with faster metabolic rates tend to produce more carbon dioxide. Larger people do, too. Certain smells may also make you a target, such as the lactic acid exuded during exercise. Ever wonder why that sweaty jog came with so many bug bites? Now you know.

Using a variety of proven controls, you can keep mosquitoes at bay while staying healthy and avoiding impacts to your environment. That makes it easier to sleep at night—uninterrupted.