DFW pest seasons: what to watch for through the year

Around Dallas-Fort Worth, pest activity tends to follow the weather more than the calendar: termite and ant swarmers often show up in late winter and spring, mosquitoes and fire ants are busiest through the warm months, and rodents and crickets commonly press toward buildings as fall cools off. Treat this guide as general, weather-dependent guidance rather than a precise schedule. Timing shifts from year to year with temperature, rainfall and how early or late the seasons turn.

How should you use a seasonal pest guide in North Texas?

Use it as a watch list, not a countdown. A warm, wet stretch can bring swarmers out early, and a cool spring can push fire ant activity later. Texas A&M AgriLife's own guidance shows this kind of spread across the state: subterranean termite swarming can begin in South Texas in January and February, while the Panhandle may not see swarms until April and May. DFW sits between those extremes, so local timing can land anywhere in that window.

A few ground rules for reading the seasons below:

1. Watch the conditions, not just the month. Warmth plus rain is a common trigger for many pests.
2. Expect overlap. Spring pests can linger into summer, and summer pests can run late into fall.
3. Keep insects and arachnids separate in your head. Scorpions and spiders are arachnids, a different group from ants, termites and roaches, and they call for different habits and prevention.
4. When in doubt, identify the pest before acting. The right response depends on getting the name right.

Late winter into early spring: who rides into town first?

This is swarmer season. Two wood-associated insects get the most attention.

Carpenter ants. Texas A&M notes that carpenter ants are often first noticed in late winter and early spring, when hundreds of winged reproductives may appear in a home over several days. Small piles of sawdust-like debris (called frass) near a hole in wood can point to a nest.

Subterranean termites. Across Texas, termite swarmers are usually encountered from March through April. In most parts of the state, swarming often starts with a "swarm tube" in late March or early April: a small dab of mud on an indoor wall that later becomes an exit for swarmers.

What to do in this window:

• Learn the difference between winged ants and termite swarmers. Our guide to termite swarmers vs. flying ants walks through antennae, waists and wings.
• If swarmers emerge indoors, take it seriously. Texas A&M says that swarming termites inside the house usually indicate an active infestation.
• Check foundation walls, crawl space piers and utility penetrations for mud tubes.

See the profiles for subterranean termites and carpenter ants.

Spring: when do fire ants get busy again?

Red imported fire ants are not native. They came from South America, arrived in the United States around the 1930s and reached Texas in the 1950s. Today they are found throughout much of DFW, and new mounds commonly pop up after spring rains.

Spring is a common time to start a fire ant plan, but North Texas often runs a little behind the rest of the state. Texas A&M has advised that homeowners in north central Texas may need to wait a few weeks before broadcasting bait because of cooler soil temperatures. Fire ants usually forage actively once the soil is around 70°F at a 1-inch depth.

What to do in this window:

• Walk the yard after rain and note where mounds appear.
• Read up on the two-step fire ant method before buying anything.
• Teach kids to spot and avoid mounds.

See the red imported fire ant profile.

Summer: when does mosquito season run in Dallas County?

Dallas County Health and Human Services tells residents that mosquito season runs from May to November and that they should be on heightened alert during those months because mosquitoes can spread West Nile virus. The county's "Fight the Bite" guidance is built around a few simple habits:

1. Use an insect repellent that contains DEET, picaridin or oil of lemon eucalyptus, following the label.
2. Wear long, loose, light-colored clothing outdoors, especially at dusk and dawn.
3. Drain standing water, and change water in wading pools, pet dishes and birdbaths several times a week.
4. Limit time outdoors at dusk and dawn, when mosquitoes are most active.

Our mosquito dump-and-drain checklist turns the draining step into a weekly routine. See the mosquitoes profile.

Scorpions in the heat

Striped bark scorpions are arachnids, not insects. They climb walls and trees and are often found in attics. Texas A&M notes that during periods of hot weather, scorpions may move into living areas to escape high attic temperatures. Our guide on keeping scorpions out of North Texas homes covers sealing and cleanup. See the striped bark scorpion profile.

Big roaches from the drains

American cockroaches are large, reddish-brown roaches that live in sewers and moist outdoor areas. Texas A&M notes that they can move through sewer pipes and enter kitchens and bathrooms through drains. Keeping drain covers in place and sealing gaps around plumbing helps. See American cockroaches and why roaches show up after rain.

Fire ants in midsummer

Fire ant baits are commonly applied from late spring through summer in North Texas. In hot months, Texas A&M suggests applying bait in the late evening, since summer morning applications leave bait exposed to heat and sun before ants come out to forage.

Late summer and fall: what comes calling as the weather turns?

This stretch often brings the most variety.

Yellowjackets. Texas A&M notes that yellowjacket colonies are most often a problem in late summer and fall, when they grow large. Mature colonies can hold thousands of wasps, often underground or in other voids. Watch for wasps going in and out of a hole in the lawn, and keep mowers and kids away from it. See the yellowjackets profile.

Crickets. Field crickets commonly swarm in late summer and early fall, often for about four to six weeks, and they gather around bright lights. Turning off unneeded outdoor lights and sealing gaps around doors and windows helps. See the crickets profile.

Fire ants, round two. Fall is the preferred window for broadcast baiting in the Two-Step Method. Texas A&M recommends baiting from late August to mid-October, when the ground and grass are dry and no rain is expected for 24 to 48 hours.

Rodents. As temperatures drop, Texas A&M AgriLife experts expect mice and other pests to seek shelter indoors. Their exclusion advice is to seal gaps of 1/4 inch or more with steel wool or expanding foam sealant, seal around pipes and conduits, and install door sweeps. Texas A&M training material notes that mice can get through a dime-sized hole or a 1/4-inch crack, and rats through a quarter-sized hole or 1/2-inch crack. Roof rats tend to nest above ground and favor mature vegetation, vines and trees, so trim branches back from the roofline. Our fall rodent-proofing checklist goes room by room. See house mice and roof rats.

Winter: is it really quiet season?

Quieter outdoors, maybe, but not empty. Texas A&M notes that house mice do not hibernate and nest in warm areas close to food. Indoor pests such as roaches and rodents keep going wherever they find warmth, food and water.

Winter is a good time to get ready for spring:

1. Inspect the attic, garage and crawl space for droppings, gnaw marks and nesting material.
2. Repair door sweeps, weatherstripping and torn window screens.
3. Move firewood, lumber and debris away from the foundation.
4. Clear gutters and fix leaks so moisture does not build up near the house.
5. Mark your calendar loosely for swarmer season, and plan to watch windowsills and light fixtures once warm, rainy days return.

Ride the circuit: a year-round checklist

No matter the season, a few habits make a home less inviting to almost every pest on this list:

1. Cut off water. Fix leaks, empty standing water and keep drains covered.
2. Remove shelter. Clear debris, woodpiles and clutter near the foundation.
3. Close the gaps. Seal cracks, plumbing penetrations and gaps under doors.
4. Rethink outdoor lighting. Bright all-night lights draw insects, and insects draw the predators that eat them.
5. Identify before you treat. If you use any pesticide, the label is the law; read it fully and follow it exactly. Our guide on how to read a pesticide label explains the key sections.

For the bigger picture, see integrated pest management at home.

When to get help

Call a licensed pest professional if termites swarm indoors, if you find mud tubes on your foundation, if a yellowjacket nest is near a doorway or play area, or if rodents keep returning after you have sealed obvious gaps. In Texas, structural pest control licenses are issued by the Texas Department of Agriculture's Structural Pest Control Service. For stings, bites or a pesticide exposure, contact Poison Control at 1-800-222-1222 or seek medical care. Call 911 for trouble breathing or other severe reactions.

This field guide is educational and does not offer treatment bookings.