Are Certain Plants the Key to Mosquito Control? Experts Weigh In

Do a quick search for “plants that repel mosquitoes,” and you’ll get a ton of hits for everything from mint to lavender. But while it may sound like a great idea to grow certain plants around a patio or deck to keep mosquito bites at bay, it’s unfortunately not that simple.

The science behind the concept is a little murky. “Mosquitoes kill nearly 1 million people each year through the deadly pathogens they transmit,” says entomologist Elmer Gray, a researcher and public health specialist at the University of Georgia. “Billions of dollars have been spent trying to solve these issues. If it was as simple as having a few mosquito-repelling plants on the stoop, I believe people in these stricken communities would have worked it out years ago.”

While it’s true that some plants release chemicals to keep from being eaten by insects, there’s no evidence that planting a bunch of them keeps mosquitoes away from people. “Why would a plant produce a volatile material to repel mosquitoes?” says Gray. “Mosquitoes are no risk to a plant. It is also physiologically expensive for a plant to produce volatile chemicals.”

That means plants aren’t just indiscriminately releasing these compounds around the clock as some sort of magical force field with which you can surround yourself.

Do plants repel mosquitoes?

The idea of plants as repellents has remained popular for decades. “People like the idea of ‘green’ pest control and think the answer is always found in nature,” says Chris Hayes, PhD, extension associate professor of structural pest management at North Carolina State University. “Some research has found plant-derived essential oils have repellent properties, but these were extracted and processed from certain parts of specific plants and then tested in a lab setting, which is not the same as the real world.”

Also, just because an essential oil has a repellent effect doesn’t mean the plant itself does. “Where a plant product might have some repellency to insects, that should not be conflated with the plant itself being repellent because those extracts used for testing are not going to be volatilized and dispersed by the plant unless it’s disturbed or crushed,” says Johnalyn Gordon, PhD, assistant professor of the University of Florida IFAS Fort Lauderdale Research and Education Center.

Another problem with relying on plants as repellents is that it could leave you vulnerable. Mosquitoes don’t just transmit serious diseases in far-away places; there are plenty of mosquito-borne diseases, such as West Nile virus, encephalitis, and even isolated cases of dengue, right here in the U.S.

The bottom line? “It’s risky if you aren’t using reliable protection in certain situations to prevent disease transmission,” says Hayes.

If you do want to grow these plants that are advertised to repel mosquitoes because they’re beautiful and fragrant, go ahead. “If it gives you peace of mind, plant them. It’s not going to hurt anything, but they’re not going to protect you,” says Hayes.

Are there effective plant-based repellants?

There are several effective, EPA-approved insect repellents that are derived from plants. “The repellent active ingredient must be extracted from the plant material in some manner and formulated into a safe, effective, topically-applied product,” says Gray.

Look for EPA-approved repellents containing plant-derived ingredients, including:

• Oil of lemon eucalyptus (OLE)
• Para-methane-diol (PMD), a synthetic version of the OLE active ingredient
• Oil of citronella, which is used in EPA-approved formulations
• Catnip oil, derived from Nepeta cataria, or catmint, which is used in EPA-approved formulations
• 2-undecanone, derived from the leaves and stems of wild tomato plants, also has EPA-approved formulations

How can you protect yourself from mosquitoes?

There are plenty of ways to reduce your exposure to mosquitoes and their diseases.

• Limit the places they breed. All mosquitoes breed in standing water, so eliminate sources around your home such as tarps, kiddie pools and saucers beneath flower pots. Change the water in birdbaths every few days, says Gray.
• Wear EPA-registered repellants. The registration process requires safety and efficacy data to be submitted to the EPA, says Gordon.
• Use mosquito dunks. If you can’t get rid of standing water, use mosquito dunks or granules containing Bacillus thuringiensis (Bti), a naturally occurring bacterium that affects only mosquito larvae and is not toxic to bees, fish, frogs, birds, pets, or people, says Gray.
• Wear long sleeves and light–colored clothing, which makes you harder for mosquitoes to spot, says Gray.

What does research say about plants as repellents?

Here’s how a few plants commonly recommended to repel mosquitoes actually stack up when it comes to the research.

Citrosa (Pelargonium x citrosum)

This plant is often sold as a “mosquito plant” at big-box retailers. Research has found the plant doesn’t repel mosquitoes. In fact, it may actually attract the pests instead.

Citronella grass (Cymbopogon spp.)

Studies have found Citronella plant oil has repellent effects, and it’s used as an ingredient in some EPA-approved plant-based formulations.

Rosemary (Rosmarinus officinalis)

In a lab setting, rosemary essential oil showed promising larvicidal properties on some mosquito species, but the plant itself wasn’t tested.

Catnip (Nepeta cataria)

Studies have shown that the essential oil provides good protection against certain mosquito species. It’s used in some EPA-approved repellants.

Basil (Ocimum basilicum)

Basil extracts were found to have larvicidal effects against certain mosquito species in a lab setting. As in similar cases, the plant itself was not tested.