How to Get Rid of Mosquitoes in Your Backyard

Cost: free. Effort: about 15 minutes a week. Every credible authority ranks this first. The CDC instructs: "Once a week, empty and scrub, turn over, cover, or throw out any items that hold water" — tires, buckets, planters, toys, pools, birdbaths, flowerpot saucers, and trash containers. NH DHHS adds the number that makes it urgent: "In warm weather, mosquitoes can breed in any puddle that lasts more than 4 days." A single female lays 100–300 eggs, so one overlooked saucer becomes a swarm. UNH Extension specifically flags tree holes, tarps, corrugated drainpipes, pool covers, and rain barrels as prolific New Hampshire mosquito producers. Start this by April 1 and continue through the first hard frost. No spray, trap, or gadget substitutes for removing the water where mosquitoes are born.

Cost: $5–$20 a bottle. The EPA registers six proven active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE/PMD), 2-undecanone, and catnip oil. Typical protection durations from Poison Control and EPA registration data are substantial: DEET at 20–30% lasts many hours, picaridin 20% lasts 8–14 hours, IR3535 20% lasts 7–10 hours, and OLE/PMD 30% lasts about 6 hours (though OLE is not for children under 3). Consumer Reports testing across more than 50 products consistently finds 25–30% DEET products outperform, with Repel Lemon Eucalyptus as the best DEET-free option — and CR explicitly warns against "natural" essential-oil repellents that fail in under an hour. In a state with confirmed EEE, WNV, and Jamestown Canyon Virus, a registered repellent is your most reliable personal defense.

Patio fans are the most underrated tool on this list. Mosquitoes are weak fliers — NH DHHS cites a typical flight speed of just 1–1.5 mph — so moving air overwhelms them. Hoffmann & Miller (2003) in the Journal of Medical Entomology found fan-generated wind alone reduced mosquito orientation by 74%, landings by 75%, and probing by 70%, partly by killing lift and partly by diluting the CO2 and skin-odor plumes mosquitoes track. Aim for at least 1,000 CFM directed low across seated body level. A $30–$300 fan is often the difference between an unusable patio and a comfortable one.

Cost: $8–$25 a season. Some water simply cannot be drained — rain barrels, ornamental ponds, unused pools, tree holes, clogged gutter sections, and animal troughs. For these, Bti (Bacillus thuringiensis israelensis) is the answer. It is a naturally occurring soil bacterium whose toxins activate only in the alkaline midgut of mosquito, black-fly, and fungus-gnat larvae, so the EPA states plainly that "Bti has no toxicity to people" and it is approved for organic farming with no documented resistance after decades of use. Summit Mosquito Dunks release Bti for about 30 days per dunk and cover roughly 100 square feet of water surface. Bti does not kill adult mosquitoes — it is a larvicide that prevents new ones from ever emerging, which makes it the perfect complement to source reduction.

It makes the most sense for large wooded or wetland-adjacent properties where source reduction cannot keep up, homes with children, outdoor workers, or horses because of EEE risk, properties hosting outdoor events, and towns flagged on the annual NH DHHS arbovirus map. Just as important is what to skip. Rutgers Extension and NH DHHS agree that bug zappers, ultrasonic devices, citronella wristbands, Vitamin B supplements, and incense have no demonstrated repellent effect for homeowners. FTC enforcement actions against Aromaflage, Viatek Mosquito Shield Bands, and Lentek MosquitoContro confirm how much money these categories waste. Live "repellent plants" also disappoint — Colorado State Extension notes none repel mosquitoes merely by growing in a landscape.