Trap mosquitoes
Traps are the most visible part of what we do — and it’s where we started. When the committee launched, we partnered with Biogents, the gold standard in residential mosquito trapping, to secure a deep group discount for Capitol Hill residents. It's how 1,400 households became a neighborhood-scale deployment almost overnight.
But traps are one piece of a larger system. You don't need to purchase anything to participate — tossing standing water and treating with BTi costs little to nothing and in many ways matters more. If you're ready to add trapping to the mix, here's everything you need to know.
Check out our FAQs for answers to common questions from our community on traps.
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Bucket of Doom
Cost: Free-$
Targets: egg-laying females
How it works: The most basic trap. A black bucket filled with water and a little organic matter mimics an irresistible breeding site — females fly in, lay their eggs, and a BTi dunk kills the larvae before they hatch. No power, no moving parts, no chemicals beyond the BTi.
Maintenance: Refresh the dunk every 3–4 weeks and add more water if it has evaporated..
DIY: You can build one for the cost of a bucket and a dunk. Black buckets work best (they’re cozy!)
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BG-GAT (Gravid Aedes Trap)
Cost: $$
Targets: egg-laying females
How it works: You can think of the GAT as an upgraded Bucket of Doom — same standing-water lure, but with a funnel on top, a sticky card inside and a net to prevent mosquitoes from ever laying eggs. Females enter to lay their eggs, get caught on the card, and don't make it back out.
Each female caught stops 50–100 offspring that cycle. No power required.
Maintenance: Replace sticky cards every two weeks. Refresh organic material and top up water as needed
Ordering details: Biogents has organized a community discount on GAT traps (available in packs of 2 traps for $50 and packs of 12 traps for $250) for Itty Bitty Mosquito Population Committee households. You will also want to order extra sticky cards (also discounted!) to last you through the season.
Click below and then click “I want fewer mosquitoes” to order GAT traps at a discount. -
BG-Mosquitaire
Cost: $$$
Targets: host-seeking females (the ones actively trying to bite you)
How it works: The Mosquitaire doesn't mimic a breeding site — it mimics a person. A fan and Biogents' proprietary BG-Sweetscent lure attract mosquitoes hunting for a blood meal. They get drawn in, can't escape, and dehydrate. Requires a power outlet and runs best left on 24/7 to catch as many mosquitoes as possible. The trap’s energy usage is minimal.
Adding CO2 — via canister or a DIY yeast-based setup — boosts catch rates by up to 400% and expands coverage to other species like Culex [See below for more details on CO2].
Maintenance: Replace the Sweetscent every 6-8 weeks. Change the catch bag regularly, at minimum every time you replace the Sweetscent. To dispose caught mosquitoes, freeze for 2–3 hours or leave in direct sun to dehydrate.
Ordering details: Biogents has organized a community discount on Mosquitaire traps ($150 for one traps and $250 for two) for Itty Bitty Mosquito Population Committee households. You will also want to order extra Sweetscent sachets to last you through the summer.
Click below and then click “I want fewer bites” to order a Mosquitaire at a discount.
Where to put your trap
Placement matters more than most people expect. A few rules of thumb:
Find shade and wind protection. Mosquitoes seek out shady spots and are weak fliers — which is also why a fan is one of the best ways to keep them off you when you're sitting outside. A trap in a sunny, breezy spot underperforms. Under stairs can also provide a nice shady, sheltered spot, and nobody's lingering there long enough for mosquitoes to change course and bite instead.
Test, then nudge. Especially in small yards — find a reasonable spot, run it for a bit, then move it 6–12 inches and see if catches improve. Small adjustments can make a real difference.
Skip medians, tree boxes, and playgrounds. Roads create barriers mosquitoes have trouble flying around, so a median trap won't do much for your yard. Tree box traps also get hit by dogs, which interferes with the lure. Playgrounds invite curious kids. If street-side mosquitoes are a problem, look for the source: drains, catch basins, sidewalk grates.
Rain is fine. All traps are weatherproof.
Larvae can survive a freeze. Don't assume winter reset things — treat and trap early in the season before populations build.
Work with your neighbors
Mosquitoes don't respect property lines. A trap on the alley fence line can work for two households at once. Talk to your immediate neighbors about coordinating placement — it's the most efficient way to cover a block.
You are welcome to purchase and deploy traps individually, but the committee is also coordinating trap deployment through block captains. Find your block captain → if you want to collaborate with your neighbors.
When working with your neighbors, space traps every 2–3 houses. In blocks with heavy vegetation, aim for every 2nd house. Lighter vegetation, every 3rd or 4th. Consistent coverage across a block matters more than any single well-placed trap.
At the end of the day, mosquitoes are wild creatures and don’t play by a rulebook. Experiment to see what works for your property and block!
A great shaded spot for a GAT trap under a lot of vegetation
This GAT trap is well protected from wind under dense tree foliage.
These dense shrubs are a perfect spot to tuck a trap.
Lots of vegetation provides a protected area that mosquitoes will hang out in.
Tuck your traps under bushes!
That shady damp area between porches is a perfect place to try a trap. Just be careful if you often sit right above it!
Don't have a good shady, vegetated spot? Try under the stairs.
Adding CO2 to your Mosquitaire setup
Your Mosquitaire can perform really well just with the sweetscent packets. However, we’ve been impressed by how much larger our catch rates have been with the addition of carbon dioxide. Using a canister adds more expense and complexity to your setup steps, but once you’re setup it lasts for weeks and refills are much simpler and less expensive going forward. DIY methods are super cheap and easy but will only last you a few days.
DIY CO₂
Mix 2.5–3 cups warm water, 1 cup sugar, a pinch of salt, and ½–1 tsp active dry yeast in a bottle or bowl beside the trap - you could also put the mixture inside but then you’d have to clean it. The fermentation emits CO₂ for a few days. This is a cheap way to try it before committing to a tank.
Canister CO₂
Purchase a tank through a local supplier and a CO₂ hookup adapter from Biogents. A timer add-on limits CO2 to peak mosquito hours and extends tank life significantly. Biogents recommends using a 10 lb or 20 lb food/beverage-grade non-siphon CO₂ tank. For reference, a 20lb canister cost roughly $250 with 20 lb CO₂ refill costing ~$40.
Where to purchase
You can typically get CO₂ tanks/refills from:
Airgas
Welding supply stores
Beverage gas suppliers
Homebrew stores
Restaurant supply companies
Two suppliers close to Capitol Hill:
Robert’s Oxygen in Hyattsville
Airgas in Alexandria, VA
Most suppliers offer both retail and tank exchange programs.
Tips & Tricks
Make sure the connection from the adapter to the CO₂ tank is super tight otherwise your CO₂ won’t last long. We suggest buying a 28mm wrench, if you use slip joint pliers you may not be able to get it tight enough.
Put soapy water on the connection and see if it bubbles and check for leaks.
Open the valve on the CO2 tank open the valve all of the way, if you only open it partway a bit of gas will seep out of the valve on the top of the tank.
To check if it’s working after it’s turned on, put the end of the hose into a glass of water and see if it emits bubbles. See here →