Orkin released its 2026 Mosquito Cities List this week, the company's annual ranking of U.S. metropolitan areas by residential mosquito treatment volume. Los Angeles took the top spot for the sixth consecutive year, followed by Chicago and New York. The full top 50 is dominated by familiar names — but the year-over-year movement tells a more interesting story than the leaderboard does.
For homeowners trying to decide whether to invest in yard-level mosquito control this season, what the list actually measures matters as much as where your city ranks.
This is the part that gets glossed over in most coverage. The Mosquito Cities List ranks metropolitan areas by the number of new residential mosquito treatments Orkin performed between March 2025 and March 2026. It is a measure of where Orkin's residential customer base is growing fastest, which is closely correlated with — but not identical to — where mosquitoes are actually most abundant.
The distinction matters because the ranking reflects both biological pressure and consumer behavior. A city can climb the list because mosquito populations expanded, or because mosquito awareness expanded, or because Orkin's marketing footprint expanded in that metro. In practice, all three usually move together. The list is a strong directional signal, not a precise census.
Milwaukee jumped 15 positions to claim the #23 spot, the largest single-year move on the list. Minneapolis climbed six positions to #13. Traverse City, Michigan made the list for the first time. So did Springfield, Illinois and Greenville, North Carolina. Sacramento returned after several years off, and Phoenix re-entered the top 50.
Orkin entomologist Shannon Sked attributed the shift to two converging factors: climate conditions that are extending suitable habitat northward, and the geographic expansion of the yellow fever mosquito (Aedes aegypti) into regions that historically didn't see significant populations. Both are well-documented trends in vector biology literature. The yellow fever mosquito is the daytime-biting, container-breeding species responsible for Zika, dengue, and chikungunya transmission where those diseases are present.
The flip side: Miami and Greensboro, North Carolina each dropped five positions. That doesn't mean fewer mosquitoes — it means slower year-over-year growth in treatment volume than other cities saw.
The ranking is national news. Your yard plan is a local question, and the right answer is independent of where your city ranks. The decision tree is the same in Los Angeles, Milwaukee, or Atlanta: source reduction first, larvicide second, adulticide last.
Source reduction is exactly what it sounds like — eliminate the standing water where mosquitoes breed. Aedes species (the ones expanding most aggressively) breed in containers as small as a bottle cap. Walk your yard once a week and empty anything that holds water for more than three or four days: pot saucers, kids' toys, clogged gutters, tarps, low spots in lawns. This single habit reduces local mosquito populations more than any spray.
Where standing water can't be eliminated — ornamental ponds, French drains, large tree hollows — Bti dunks are the gold standard. Bti is a naturally occurring bacterial larvicide that targets mosquito larvae specifically, with no risk to fish, pets, beneficial insects, or pollinators. A single dunk treats up to 100 square feet of surface area for around 30 days.
Yard barrier sprays — what Orkin and most quarterly services apply — work as the third layer, killing adults on contact and providing residual on foliage. They are effective for a 30-to-60-day window depending on rainfall and product. The right product depends on the species pressure in your specific area; our AI photo ID tool can confirm which Aedes, Culex, or Anopheles species is biting in your yard, which determines the right treatment.
The Mosquito Cities List is most useful as a prompt for timing. If you're in a high-ranked city or a fast-rising one, the calendar matters more than usual. Mosquito populations build through May and June and typically peak in July through September in most of the U.S. Source reduction is most effective when started early — before the first generations establish — and least effective once populations are at peak. The cities climbing fastest this year are precisely the ones where homeowners are most likely to be caught unprepared by the speed of the seasonal build-up.
If you want to plan around your region's specific peak weeks, our pest season calendar has month-by-month mosquito pressure data for all six U.S. regions.