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Pests in New Castle County

Delaware’s most populated county mixes century-old rowhomes in Wilmington with newer subdivisions around Middletown. Older housing means more gaps for rodents and roaches; wooded developments bring ticks.

Towns: Wilmington · Newark · Middletown · Bear · New Castle · Hockessin · Claymont · Townsend · Pike Creek

Top pests in New Castle County

Mice & RatsHome

Move inside as nights cool. Droppings and gnawing are the first signs.

Peak: Oct – FebTreated by Mosquito & Pest Authority

CockroachesHome

German roaches live indoors year-round; American roaches come in from outside.

Peak: Jun – SepTreated by Mosquito & Pest Authority

TermitesHome

Subterranean termites swarm in spring. A must-check before any home sale.

Peak: Mar – MayTreated by Mosquito & Pest Authority

Stink BugsHome

Gather on sunny walls in fall and slip in around windows.

Peak: Sep – NovTreated by Mosquito & Pest Authority

TicksYard

Deer ticks carry Lyme. Found in tall grass, leaf litter and wooded edges.

Peak: Apr – Jul, Oct – NovTreated by Mosquito & Pest Authority

Spotted LanternflyYard

Invasive planthopper spreading south. Report and destroy egg masses.

Peak: Jul – OctTreated by Mosquito & Pest Authority

Towns in New Castle County

Local pest notes and seasonal timing for 9 New Castle County communities.

WilmingtonWatch for: mice & rats, cockroaches, bed bugs NewarkWatch for: bed bugs, cockroaches, ticks MiddletownWatch for: ants, mice & rats, mosquitoes BearWatch for: mosquitoes, ticks, ants HockessinWatch for: ticks, ants, spotted lanternfly New CastleWatch for: termites, mice & rats, mosquitoes ClaymontWatch for: spotted lanternfly, mosquitoes, Asian longhorned ticks TownsendWatch for: ticks, Asian longhorned ticks, mice & rats Pike CreekWatch for: ticks, Asian longhorned ticks, mosquitoes

Pest seasons in New Castle County

Spring: Termite swarmers show up on warm spring days, ants move indoors, and DNREC reports longhorned ticks in New Castle County during the spring and summer. Spotted lanternfly nymphs hatch in spring; the Department of Agriculture asks residents to destroy them.
Summer: DNREC’s Mosquito Control Section monitors and treats mosquitoes from ditches, stormwater ponds, wet woodlands and coastal salt marshes during the warmer months. Adult spotted lanternflies appear on trees and decks.
Fall: Mice and stink bugs look for a way inside as nights cool. Spotted lanternflies lay egg masses in the fall, and blacklegged tick adults become active again.
Winter: Rodents stay busy inside walls and basements. DNREC says blacklegged tick adults are most active in the late fall and winter, so tick checks still matter on mild days.

New Castle County pest questions

Is spotted lanternfly in New Castle County?

Yes. The Delaware Department of Agriculture says spotted lanternfly was first detected in New Castle County, and populations are now confirmed in all three counties, with a quarantine covering the entire state. Inspect vehicles and anything you’re moving, and remove and destroy egg masses.

Who do I contact about a mosquito problem in New Castle County?

DNREC’s Mosquito Control Section serves New Castle County from its Northern Delaware Office in Glasgow. For larger breeding sites such as wetlands, roadside ditches or stormwater basins, contact that office. DNREC also posts planned aerial and truck spraying on its Spray Zone Notification map and spraying calendar.

Is the Asian longhorned tick in New Castle County?

Yes. DNREC first found it in northern New Castle County in 2019 and now reports longhorned ticks in a variety of habitats in New Castle and Kent counties during the spring and summer. They infrequently bite people and are more often seen on pets or livestock.

Do I need to worry about ticks in winter?

Yes. DNREC says ticks can be active year-round in Delaware, and blacklegged (deer) tick adults are most active in the late fall and winter. Keep checking yourself, kids and pets after time outdoors.

Where can I get a tick identified?

DNREC’s tick program has an online tick identification form at de.gov/ticks; a photo of the top of the tick helps. Delaware does not offer tick pathogen testing, so talk to your doctor or veterinarian if you’re worried about illness.

Sources

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