Sterile mosquitoes vs repellents
Repellents protect a person for a few hours. Sterile males shrink the population in the yard.
An EPA-registered skin repellent such as DEET, picaridin or oil of lemon eucalyptus is the right protection for a person outdoors, and the CDC recommends it.¹ Citronella candles and many essential-oil products have weak or unverified effects. Sterile male mosquitoes do a different job: as biological control that's safe for people, pets and pollinators, they reduce the population of the species released on your property over weeks, so there are fewer mosquitoes to repel.
1. CDC, "Mosquito Bite Prevention (United States)," CS356185-A, December 2, 2024, https://www.cdc.gov/mosquitoes/pdfs/mosquitobitepreventionus_508.pdf.
How repellents and devices work
Four kinds of products, four very different levels of evidence.
Skin repellents. The CDC recommends EPA-registered products with one of 6 active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone. Higher percentages protect for longer.¹ A registration number means the maker gave the EPA data on the product's safety and effectiveness.² In a 2017 test, oil of lemon eucalyptus and a high-strength DEET spray both cut mosquito attraction to a person by more than half.³
Citronella candles. In the same 2017 test, a citronella candle had no significant effect at 1 meter.³ An earlier study measured 29% repellency for citronella candles indoors, well below candles made with geraniol.⁴
Area repellent devices. Small heated or fan-driven units release a volatile insecticide, such as metofluthrin or allethrin, into the air around a seating area.⁵ In Louisiana field tests, two such devices lowered mosquito numbers at the sites where they ran.⁶ A wearable metofluthrin clip-on reduced attraction in the 2017 test.³ The CDC notes these products have not yet been adequately evaluated in peer-reviewed studies for preventing illness.⁵
Essential-oil yard sprays. Many are sold as "minimum risk" pesticides, which the EPA exempts from registration.⁷ Exempted products are not evaluated by the EPA, so the agency can't verify their effectiveness claims.⁸ The CDC says the effectiveness of non-registered repellents, including some natural ones, is not known.¹
1. CDC, "Mosquito Bite Prevention (United States)," December 2, 2024, https://www.cdc.gov/mosquitoes/pdfs/mosquitobitepreventionus_508.pdf. 2. EPA, "Find the Repellent that is Right for You," https://www.epa.gov/insect-repellents/find-repellent-right-you. 3. Rodriguez et al., Journal of Insect Science 17(1):24, 2017, New Mexico State University, https://doi.org/10.1093/jisesa/iew117. 4. Müller et al., Journal of the American Mosquito Control Association 24(1):150, 2008, https://pubmed.ncbi.nlm.nih.gov/18437831/. 5. CDC Yellow Book, "Mosquitoes, Ticks, and Other Arthropods," https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html. 6. Collier et al., Journal of the American Mosquito Control Association 22(3):444-450, 2006, https://pubmed.ncbi.nlm.nih.gov/17067044/. 7. EPA, "Minimum Risk Pesticides Exempted from FIFRA Registration," https://www.epa.gov/minimum-risk-pesticides. 8. EPA news release, November 9, 2009, on minimum risk skin-applied repellents, https://www.epa.gov/archive/epapages/newsroom_archive/newsreleases/bf33e4a4ce74a66d8525766900646306.html.
How sterile males work
Repellents push mosquitoes away from you. Sterile males mean fewer are born, with nothing to wear, light or reapply.
It's biological control that's precisely targeted: it affects only the two mosquito species we release, so it's safe for everyone in the yard, from kids and dogs to bees.
Four steps to fewer mosquitoes
Side by side
Sterile males against the four products people reach for most.
| Compared on | Sterile males (SMF) | Skin repellents | Citronella candles | Area repellent devices | Essential-oil yard sprays |
|---|---|---|---|---|---|
| What it does | Stops wild females from producing offspring and collapses the population | Keeps mosquitoes off the person wearing it | Scented smoke near the candle | Releases a volatile insecticide near a seating area | Scented treatment on plants |
| Coverage area | The property in your program | One person | No significant effect at 1 m in one test¹ | A patio or seating zone | Treated foliage |
| Reaches hidden breeding sites | Often. Males find wild females on their own, including in gutters, drains, dense plants and the yard next door | No | No | No | No |
| How long it lasts | Builds over the season while releases continue | Hours; reapply as directed² | While it burns | While it runs | Not reviewed by the EPA³ |
| Effect on other insects | None. Only the two mosquito species we release. | Applied to skin only | Scent only | Active ingredient is an insecticide⁴ | Varies by product |
| Pets and kids | Nothing applied; males don't bite | Follow the label; no OLE or PMD under age 3, no repellent under 2 months² | Open flame | Follow the label | Follow the label |
| Maintenance | A release plate twice a month (once a month in winter), about a minute; on commercial sites, our team or your staff release | Reapplying | Lighting and replacing | Refill cartridges | Repeat treatments |
| Cost model | Quoted for your property | Low, ongoing | Low, ongoing | Device plus refills | Per product or per treatment |
| Best for | Fewer mosquitoes across the yard all season | Every person outdoors at dusk and night | Ambience | Supplementing protection at a table | Little published evidence |
1. Rodriguez et al., Journal of Insect Science, 2017. 2. CDC, December 2, 2024. 3. EPA, minimum risk pesticides and 2009 news release. 4. CDC Yellow Book.
When repellent is the right choice
Almost always, for the person. A program never replaces it.
Skin repellent protects you wherever you go: the ballfield, the trail, a friend's yard. It also covers the mosquitoes sterile males don't. Our releases target the Asian tiger and yellow fever mosquitoes, the ones that bite in yards by day and at dusk. Night-biting mosquitoes, which the CDC notes typically peak after sunset, around 10 to 11 p.m., are not affected by our program.¹ For late evenings, wear an EPA-registered repellent and follow the label.
Area repellent devices can be a sensible extra at a table. Citronella candles are fine for the mood, just don't count on them.
1. CDC Yellow Book, "Mosquitoes, Ticks, and Other Arthropods," https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods.html.
Using them together
The best evening outside uses both: fewer mosquitoes, and protection from the rest.
- Sterile males all season to reduce the daytime and dusk biters breeding on your property.
- Skin repellent for anyone outside after dark, when night biters are out.
- Tip out standing water weekly, as the CDC advises: vases, saucers, buckets, toys.¹
- Long sleeves and a fan on the patio for dinner outside.
A program means you reach for the bottle less often. It doesn't mean you throw it out.
1. CDC, "Mosquito Bite Prevention (United States)," December 2, 2024.
FAQ
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1. Rodriguez et al., Journal of Insect Science, 2017. 2. Müller et al., Journal of the American Mosquito Control Association, 2008. 3. CDC, December 2, 2024. 4. Collier et al., Journal of the American Mosquito Control Association, 2006. 5. EPA news release, November 9, 2009.
Does citronella work?
Not much. A citronella candle had no significant effect on mosquito attraction at 1 meter in a 2017 study, and another study measured 29% repellency for citronella candles indoors.¹ ²
What is the most effective mosquito repellent?
The CDC recommends EPA-registered repellents with DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone. Higher percentages last longer.³
Is DEET safe for kids?
The CDC says to follow the label, not to use any repellent on babies under 2 months, and not to use oil of lemon eucalyptus or PMD on children under 3. Adults should apply it to a child's face with their hands.³
Do mosquito repellent devices for the patio work?
Some reduced mosquito numbers in field tests.⁴ They release an insecticide into the air near you, so follow the label, and still wear repellent when mosquitoes are biting.
Do natural yard sprays work for mosquitoes?
Many are exempt from EPA registration, so their effectiveness isn't reviewed by the EPA, and the CDC says the effectiveness of non-registered natural repellents is not known.³ ⁵
Do I still need repellent with sterile mosquitoes?
For late evenings, yes. Sterile males reduce the Asian tiger and yellow fever mosquitoes. Night-biting mosquitoes are not affected, so repellent is still the right call after dark.
Run a venue, HOA, resort, farm or golf course? → Commercial programs · Related: Sterile mosquitoes vs bug zappers · Sterile mosquitoes vs mosquito traps · Compare all options · Safety and regulation · See the research
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