Sterile mosquitoes vs CO2 mosquito traps
A full net isn't the same as fewer bites. Here's what each one actually changes.
CO2 mosquito traps burn propane to imitate human breath and pull mosquitoes into a net. They reliably catch mosquitoes, but controlled studies have not shown a meaningful drop in bites around the people they're meant to protect.¹ Sterile male mosquitoes are biological control that works on the next generation instead: wild females that mate with them lay eggs that don't hatch, so the local population of the species released gets smaller over weeks, safely for people, pets and pollinators.
How CO2 traps work
A trap that breathes like a person, then vacuums up whatever comes close.
Most backyard traps burn propane to produce carbon dioxide, often with heat, moisture or a scent lure such as octenol. A fan draws mosquitoes that come close into a collection net, where they die.² Because the lure mimics a human, these traps mainly catch biting insects, and moths and beetles are largely left alone.¹
The catch can be impressive. One trap in a Canadian study collected an estimated 2 million mosquitoes over 94 trap nights. Yet landing counts on people near the trap were no lower than at comparison sites, and in one year they were higher.³ A second study in southern Louisiana also found no meaningful reduction in biting.¹ A University of Florida extension factsheet notes that even "a bag full" may be a tiny share of the biting females in the area.²
Placement matters too. The American Mosquito Control Association notes that, depending on placement and wind, traps "may actually draw more mosquitoes into an area than they can possibly catch."¹
1. American Mosquito Control Association, "Traps," https://www.mosquito.org/traps/ (citing Collier et al., 2006, and Henderson et al., 2006, Journal of the American Mosquito Control Association). 2. Rutledge, C. R., "Mosquito Control Devices and Services for Florida Homeowners," ENY-692, University of Florida IFAS Extension, first published December 2003 (archival copy), https://journals.flvc.org/edis/article/view/109141. 3. Henderson, Westwood and Galloway, Journal of the American Mosquito Control Association 22(3):401-407, 2006, Winnipeg, Manitoba, 2001 to 2002, https://pubmed.ncbi.nlm.nih.gov/17067037/.
How sterile males work
Instead of catching this week's mosquitoes, sterile males stop next week's from hatching.
We release male mosquitoes that don't bite and can't father offspring. They find wild females on their own, including where sprays and traps can't reach, and each mating is one less brood. It's biological control that's precisely targeted: it affects only the two mosquito species we release. No tank or unit has to compete with your guests' breath.
Four steps to fewer mosquitoes
Side by side
How the two approaches compare on the things people ask about most.
| Compared on | Sterile males (SMF) | CO2 mosquito traps |
|---|---|---|
| What it does | Stops wild females from producing offspring and collapses the population | Lures and kills mosquitoes that fly close to the trap |
| Coverage area | The property in your program | Advertised acre-wide claims "appear to be overstated," per the AMCA¹ |
| Reaches hidden breeding sites | Often. Males find wild females on their own, including in gutters, drains, dense plants and the yard next door | No. It catches mosquitoes that fly close to the trap |
| How long it lasts | Builds over the season while releases continue | Only while it runs, with no carry-over to the next generation shown² |
| Effect on other insects | None. Only the two mosquito species we release. | Mostly biting insects; moths and beetles largely unaffected¹ |
| Pets and kids | Nothing applied to the yard; males don't bite | No chemicals; a propane tank and running unit stay in the yard |
| Maintenance | A release plate twice a month (once a month in winter), about a minute; on commercial sites, our team or your staff release | Propane tanks to replace, nets to empty, lures to refresh¹ |
| Cost model | Quoted for your property | Up-front device purchase, plus ongoing propane and lures |
| Best for | Season-long reduction of daytime and dusk biters in yards | Catching mosquitoes for counts; possibly small, sheltered, low-wind spots² |
1. American Mosquito Control Association, "Traps," https://www.mosquito.org/traps/. 2. University of Florida IFAS Extension, ENY-692 (archival), https://journals.flvc.org/edis/article/view/109141.
When a CO2 trap is the right choice
They're genuinely good at one job: catching mosquitoes so people can count them.
Public mosquito programs use CO2-baited traps every week to measure mosquito activity. A trap tells you which species are around and whether numbers are rising.
As a control tool, university extension experts say a trap may cut biting in a small area for a while when conditions line up: little wind, low mosquito numbers to begin with, and a CO2 plume strong enough to outcompete nearby people and pets.¹ If that describes your corner of the yard and you like a device you can run yourself, a trap can be a reasonable add-on. Keep it well away from where people sit.
1. University of Florida IFAS Extension, ENY-692 (archival), https://journals.flvc.org/edis/article/view/109141.
Using them together
A trap counts. Sterile males do the reducing.
If you already own a CO2 trap, it can stay. We'll tell you where it's least likely to pull mosquitoes toward your patio.
What helps most alongside sterile males is free: tip out standing water after rain, from buckets, saucers, toys and clogged gutters. For evenings when night-biting mosquitoes are out, use a skin repellent. See Sterile mosquitoes vs repellents and Sterile mosquitoes vs mosquito traps for lure traps and bait stations.
FAQ
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1. American Mosquito Control Association, "Traps," https://www.mosquito.org/traps/. 2. University of Florida IFAS Extension, ENY-692 (archival), https://journals.flvc.org/edis/article/view/109141.
Do CO2 mosquito traps work?
They catch mosquitoes, often in large numbers. Two controlled field studies could not show a meaningful drop in biting near the traps, and mosquito control experts caution against relying on traps alone.¹
Do mosquito traps attract more mosquitoes to my yard?
They can. Depending on where the trap sits and which way the wind blows, the AMCA notes a trap may draw in more mosquitoes than it can catch.¹ That's why they're usually placed away from where people gather.
How long does a CO2 mosquito trap take to work?
There's no peer-reviewed evidence that traps produce a noticeable decline in yard populations, so there's no reliable timeline.² With sterile males, you should start to feel the difference within 7 to 14 days, and it keeps improving from there.
Are propane mosquito traps safe for pets?
They don't use insecticide, and the CO2 lure mostly attracts biting insects. The main things in the yard are a propane tank and a powered unit, so follow the maker's placement and safety instructions.
Is a CO2 trap or sterile mosquito program better for a big yard?
For a whole property, sterile males are built for the job: they reduce the species released across the program area as the season goes on. A trap is better at counting mosquitoes than at protecting a large space.
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