Red Imported Fire Ants: Mounds, Stings and Control in Texas

Mounds of loose, crumbly soil with no hole on top, and tiny reddish ants that boil out and sting when you step near, mean red imported fire ants. Texas A&M's fire ant experts recommend a two-step plan: bait the whole yard when ants are actively foraging, then treat only the mounds that cause trouble. Fire ants that turn up indoors or in an AC unit or electrical box need a different, more careful approach.

For help with fire ants around your home, call or text (210) 281-1064 or book online.

How can you tell they're fire ants? #

The Texas A&M AgriLife fire ant project offers three checks a homeowner can make without a microscope:

• The mound. Fluffy, worked-up soil, often only a few inches tall in a mowed yard and easiest to spot after a heavy rain. Look closely and you won't find an entrance hole in the center.
• The workers. In one colony you'll see a mix of ant sizes, from very small to medium. AgriLife's venomous animals bulletin puts workers at 1/16 to 3/16 inch and reddish brown, with queens around 3/8 inch.
• The reaction. Poke the mound with a long stick and watch. Fire ant workers race out and climb straight up whatever is upright, the stick included. Few native ants do that.

Texas also has three native fire ant species, which AgriLife describes as less aggressive than the imported one.

A large, fuzzy, red-and-black "ant" wandering alone is not a fire ant at all; see our velvet ant guide.

Where do fire ants cause trouble around a home? #

AgriLife says the imported fire ant lives mainly across the eastern two-thirds of Texas. It was brought into Alabama around the 1930s. Colonies are big, averaging 100,000 to 500,000 workers, and in areas with single-queen colonies a single acre can hold 40 to 150 mounds.

Problem spots usually include:

• Yards and play areas, where people and pets walk over mounds.
• Inside the house. AgriLife's site-specific management page says foragers come indoors for food and water, especially in hot, dry summer weather, and whole colonies may move inside during flooding.
• AC units and electrical boxes. These offer warmth and a dry hideout. Ants chew insulation and can cause short circuits, and AgriLife estimates the electrical damage in Texas at $11.2 million a year.

What does the fire ant year look like? #

AgriLife Today added in 2026 that baits work when temperatures are around 70 degrees or warmer.

How bad are fire ant stings? #

Fire ants grip with their jaws and sting again and again, and a disturbed mound sends out many workers at once. AgriLife's medical information page describes burning and itching, followed within a day or two by a white pustule. The bulletin on venomous animals says that pustule can last a week or longer. The stings infect easily and can leave permanent scars.

Go to an emergency room right away for any of these after stings: chest pain, nausea, heavy sweating, shortness of breath, serious swelling or slurred speech. Anyone with a known sensitivity should talk to an allergist about a plan.

For ordinary stings, the CDC's guidance for outdoor workers says to brush the ants off briskly, since they hang on with their jaws, and notes that antihistamines may help.

The Two-Step Method, in plain terms #

This is the approach AgriLife's fire ant project recommends for yards.

Step 1: broadcast bait over the whole yard.

• Pick a day when the grass is dry and no rain is expected for a day or two.
• Check that ants are foraging by setting out a little bait or food. If ants find it within about 30 minutes, they're active (AgriLife's L-5070 uses a one-hour test instead).
• Use fresh bait and don't water it in.

Step 2: treat only problem mounds near doors, walkways, gardens or play areas.

Expect patience. AgriLife says it can take weeks to months to reach 80 to 90 percent control. Baiting once or twice a year keeps numbers down, and the method pays off most in yards with five or more mounds per quarter acre.

L-5070 cautions that the Two-Step plan may not be the right fit for a household where someone is highly allergic to stings.

What doesn't work #

• Kitchen remedies. Texas A&M tested baking soda, cinnamon, club soda, coffee grounds, grits and molasses, and none of them was shown to control fire ants.
• Boiling water as a cure-all. About 3 gallons poured on a mound kills around 60 percent of mounds, according to Texas A&M, and it also kills any plants it touches.
• Spraying into electrical equipment. Never drench or spray inside an electrical box or AC unit.

When should you call a professional? #

• Fire ants are in an AC unit, electrical box or other equipment. Turn off the power and have an electrician or licensed pest professional deal with it.
• A family member is highly allergic to stings.
• Ants keep coming indoors.
• Mounds keep returning in play areas despite your efforts.

Texas fire ant quarantine rules #

The Texas Department of Agriculture follows the federal fire ant quarantine. Bexar, Comal, Guadalupe, Kendall, Medina, Wilson and Atascosa counties are all on TDA's quarantined list. Moving soil, plants with soil on their roots, sod, hay or straw stored on the ground, or used soil-moving equipment out of the quarantined area requires a certificate or permit. If you're shipping or hauling those items, check with TDA first.

How Pest Trappers handles fire ants #

For Pest Trappers, fire ant treatment around a home and yard is part of general pest service. The technician inspects the yard, the foundation line, any AC pad and electrical boxes, and indoor areas where ants have been seen, then explains the treatment options that fit your property and household. Products are applied according to their labels. We don't offer lawn or turf services; our work is about the ants.

Pest Trappers LLC (TPCL #0887549) is family-owned, and we give pricing after the inspection. Call or text for a quote, or book online and the office will confirm a time.

Local fire ant pages: San Antonio, Helotes, Boerne, Fair Oaks Ranch and Leon Springs and The Dominion.

Frequently asked questions #