Getting rid of no-see-ums requires a combination of physical barriers, airflow control, breeding site elimination, and repellents. No single method works alone because these insects are tiny enough to pass through standard window screens and persistent enough to breed in any patch of damp soil or standing water near your home. Here’s what actually works.
Why They’re So Hard to Keep Out
No-see-ums (biting midges) are small enough that standard window and door screens do nothing to stop them. A regular screen has gaps they fly straight through. Their larvae don’t need open water to develop, just consistently moist soil, mud, or organic debris. That means your breeding sources could be a marshy patch in the yard, a tree hole that collects rainwater, the muddy edge of a pond, or even waterlogged mulch beds. Females can lay anywhere from 25 to over 200 eggs per batch, and a single female can produce over 1,000 eggs in her lifetime. Populations build fast when conditions are right.
They also prefer still, humid days. If you’ve noticed they’re worse on calm evenings and seem to vanish on breezy days, that’s because wind speeds above about 6 to 8 kilometers per hour (roughly 4 to 5 mph) are enough to ground them. That fact is the basis for one of the most effective indoor strategies.
Install No-See-Um Mesh Screens
The single most important home upgrade is replacing standard window and door screens with a tighter mesh. Look for 20×20 mesh screen, sometimes sold as “no-see-um screen” or “tiny mesh.” This weave is tight enough to block no-see-ums, sand flies, and gnats while still allowing reasonable airflow and visibility. Standard screens typically have a 16×18 or 18×16 mesh count, which leaves gaps large enough for biting midges to pass through easily.
If replacing all your screens isn’t practical, prioritize the windows you open most often and any doors that stay open during peak activity times, which are typically dawn and dusk. For porches and lanais, no-see-um mesh can be installed as a full enclosure.
Use Fans to Create a Wind Barrier
Ceiling fans and portable electric fans are surprisingly effective. No-see-ums are weak fliers that struggle in any breeze. Wind speeds over about 4 to 5 mph are enough to keep them from flying and landing on you. A standard box fan or oscillating pedestal fan easily exceeds that threshold.
Place fans near seating areas on porches, patios, and decks, angling them to sweep across the space where people sit. Indoors, ceiling fans on medium or high settings create an environment no-see-ums can’t navigate. This is one of the cheapest and most reliable defenses, especially for outdoor living spaces where screens aren’t an option.
Eliminate Breeding Sites in Your Yard
No-see-um larvae need moist (but not fully submerged) organic material to develop. They can’t survive drying out, so removing sources of persistent moisture is the most effective long-term population control. Walk your property and look for:
- Standing water edges: puddles, pond margins, birdbaths, clogged gutters, and saucers under potted plants
- Waterlogged soil: low spots in the lawn, over-irrigated garden beds, and poorly drained mulch
- Tree holes: cavities in trees that collect and hold rainwater
- Organic debris: piles of wet leaves, compost heaps near the house, and decaying vegetation
Fix drainage issues where you can. Fill tree holes with expanding foam or sand. Reduce irrigation frequency in beds near your patio or entry points. Even small improvements in drainage can make a meaningful dent, because larvae that dry out die. Their eggs can survive dry periods in a dormant state for months, though, so you’ll need to maintain dry conditions consistently rather than just draining a spot once.
Choose the Right Personal Repellent
Four EPA-registered active ingredients are effective against no-see-ums specifically:
- DEET: the most widely tested option for biting midges, effective up to 30% concentration (higher concentrations aren’t recommended and don’t add meaningful protection time)
- Picaridin: works well against no-see-ums and doesn’t have the greasy feel or plastic-damaging properties of DEET
- Oil of lemon eucalyptus (PMD): the plant-derived option with EPA registration, available in towelettes and liquids at 8 to 10% concentration, labeled specifically for no-see-ums
- IR3535: found in some Avon products, registered for biting midges, black flies, gnats, and mosquitoes
Apply repellent to exposed skin before going outdoors during peak hours. If you’re gardening or spending extended time outside at dawn or dusk, repellent plus a fan pointed at your work area gives you the best protection.
Skip the Essential Oils
Despite popular claims, common essential oils don’t repel or kill no-see-ums. A USDA study tested rosemary oil, peppermint, garlic oil, cinnamon, and sesame oil on colonized biting midges at concentrations up to 3%. None killed the midges even after 96 hours of exposure. More tellingly, the oils didn’t even repel the insects or prevent them from feeding when a plain sugar alternative was available right next to the treated solution. If you’re relying on citronella candles, peppermint sprays, or garlic-based yard treatments as your primary defense, you’re essentially unprotected.
Yard Barrier Sprays
For yards with heavy no-see-um pressure, barrier sprays applied to vegetation, fence lines, and shaded resting areas can reduce adult populations. The most common active ingredients in products labeled for midges are synthetic pyrethroids, which kill on contact and leave a residual layer on treated surfaces. Pyrethrin-based fogging concentrates offer a faster knockdown but shorter residual effect.
Barrier sprays work best as a supplement to breeding site elimination, not a replacement. If you’re spraying adults but leaving wet breeding grounds untouched, new generations will keep emerging. Apply treatments to shaded, sheltered areas where no-see-ums rest during the day: under shrubs, along fence lines, beneath deck overhangs, and around the edges of porches. Reapplication is typically needed every few weeks, more frequently after heavy rain.
Treating No-See-Um Bites
No-see-um bites tend to itch more intensely than mosquito bites relative to their size, and the itching can last several days. The bites often appear as small red welts, sometimes in clusters since multiple midges tend to feed at the same time.
For mild reactions, apply calamine lotion, a hydrocortisone cream, or a paste of baking soda mixed with water directly to the bites. Reapply up to three times a day until the itching subsides. Resist scratching, which can break the skin and lead to infection.
For stronger reactions with widespread itching or swelling, a non-drowsy oral antihistamine like cetirizine or loratadine can help. Some people develop increasingly intense reactions to no-see-um bites over time with repeated exposure, while others gradually become less sensitive. If bites produce large swollen areas, blistering, or signs of infection like spreading redness and warmth, that warrants medical attention.