When Does Mosquito Season Start in Delaware?
Mosquito season in the Wilmington area officially gets underway in mid-March, when DNREC's Mosquito Control Section begins its spring larvicide campaign, and runs through late October. Wilmington sits in New Castle County, the last part of the state DNREC's spring campaign reaches each year, so adult mosquito activity here typically builds a little slower in early spring than it does farther south.
Why New Castle County's Season Starts Later Than the Coast
DNREC's Mosquito Control Section starts its spring woodland-pool spraying in southern Sussex County first, then expands north into Kent and finally New Castle County over the following weeks. That sequence exists because coastal salt marsh habitat produces the earliest mosquito broods, while New Castle County's mix of urban Wilmington and inland suburbs sees adult mosquitoes emerge closer to early May. Once summer heat sets in, though, New Castle County's dense tree canopy and older housing stock hold plenty of standing water to keep activity going through fall.
Myth: Bug Zappers and Ultrasonic Devices Control Mosquitoes
Neither product does much against mosquitoes. Virginia Cooperative Extension has found that electric bug zappers kill very few mosquitoes while killing large numbers of harmless and beneficial insects instead, and that ultrasonic repellent devices haven't performed as advertised in controlled trials. Mosquito pressure tied to standing water on a Wilmington-area property won't respond to either device.
Wilmington-area mosquito season, 2026: DNREC's control season begins with coastal Sussex County in mid-March, reaching New Castle County last, with adult mosquitoes typically emerging statewide by early May and activity continuing through late October.
Cutting Mosquito Breeding Around Your Wilmington Property
Standing water is the one factor a homeowner actually controls. Check gutters, plant saucers, tarps, and any low spot in the yard after every rain, since a female mosquito needs less than an inch of water to lay a batch of eggs that can hatch within two days. Wilmington's older neighborhoods and mature tree canopy make clogged gutters and shaded low spots especially worth checking after storms.
For a look at what else is active in the area right now, see the most common summer pests in Wilmington.
Common Questions About Mosquito Treatment in Wilmington
Should I schedule mosquito treatment before I see activity in my yard?
Yes. Starting before adult mosquitoes emerge in early May puts a property ahead of the season instead of catching up once activity is already visible around established trees and landscaping.
How does treatment work for properties near Wilmington's wooded, established neighborhoods?
Treatment focuses on the shaded, moisture-holding areas mature trees create, along with gutters and low spots common in older neighborhoods, since those are the spots doing the most work to sustain mosquito activity through the season.
Can I set up a recurring plan so I don't have to think about scheduling each time?
Yes. Most properties run on a set retreatment cadence through the season, so visits happen automatically rather than requiring you to call and rebook each time.
Is mosquito treatment safe around established landscaping and gardens?
Yes, when applied by a trained technician following label directions. Products target resting and breeding sites rather than ornamental plantings, so established landscaping isn't put at risk by treatment.
Ready for mosquito season, or already dealing with activity in the yard? Call Frontline Pest Control at 443-252-3802 and we'll help you figure out the right next step.
Protect the Property You've Invested In
Frontline builds mosquito prevention into your Wilmington-area property's regular maintenance, on a schedule that runs without you having to manage it.
See Wilmington Mosquito Control