What Is a Fire Ant?

What a fire ant is and why it stings so much

“Fire ant” is the name for ants in the genus Solenopsis, but in U.S. yards it nearly always means the imported fire ants.

USDA APHIS names two species, the red imported fire ant (Solenopsis invicta) and the black imported fire ant (S. richteri), both from South America ¹.

APHIS says they likely arrived decades ago in soil on cargo ships ¹.

Workers are small, about 1/4 inch, red-brown with a shiny dark abdomen, and have two small bumps in the waist. NC State says that two-node waist sets them apart from most other local ants ³.

Their defense is what people notice first. When a mound is stepped on, many ants rush out at once. NIOSH notes fire ants both bite and sting: they grip skin with their jaws and inject venom ⁵.

Farms and wildlife suffer too. APHIS says they feed on crops and seedlings, damage equipment with mounds, push out native ants and injure young animals ¹.

How a fire ant colony starts and spreads

1. Mating flights. Winged males and females fly in spring and fall when it is 70–95°F ³.
2. A new queen digs in. Males die soon after mating. The mated female sheds her wings and digs a chamber in soil ³.
3. First brood. A new queen lays 12 to 25 eggs. Eggs hatch in 7–10 days, larvae grow 7–10 days, and adults appear about two weeks later ³.
4. Rapid growth. An established queen can lay up to 800 eggs a day ³. Workers are sterile females ³.
5. Mounds appear. Nests may go unnoticed until heavy rain, when mounds rise above the waterline. They favor sunny spots near sidewalks and driveways ³.
6. Spread. New queens fly to new ground, and people move colonies in soil, sod, hay and plants ¹⁴.

Fire ants and ants often confused with them

Ant size, color and waist shape can be hard to judge by eye. Our pest identifier walks through other clues.

Example: why one queen matters so much

This illustration uses NC State’s published figures to show how fast a colony can replace ants. It is not a forecast for any yard.

The math explains the advice. A drench or spray that misses the queen leaves a colony that can lay hundreds of eggs a day. Baits are slow because they have to be shared before they work.

Where fire ants show up on paperwork

On a lawn or ant control plan, look for whether the company uses a broadcast bait, individual mound treatments or both, how many visits a year, and whether re-treatment is included. Texas A&M suggests broadcasting bait once or twice a year ⁴.

On a nursery, sod, hay or landscaping invoice in a quarantined area, you may see a fire ant certification or treatment record. APHIS works with states to regulate those high-risk goods ¹.

On a property safety walk-through, mounds near play areas, paths and doors are worth listing because of the sting risk NIOSH describes ⁵.

Fire ant sting symptoms and danger signs

NIOSH lists these for workers; they apply to anyone stung ⁵.

• A burning feeling at the sting site.
• Red bumps that turn into white fluid-filled pustules within a day or two.
• Many stings at once, because ants swarm out of a disturbed mound.
• Emergency signs: severe chest pain, nausea, heavy sweating, shortness of breath, serious swelling or slurred speech.

What each control method does well

Why you cannot get rid of fire ants for good

Fire ants are established across huge areas. APHIS puts infestations at more than 367 million acres ¹. Even if you clear your yard, mated queens from nearby colonies land and start new ones ⁴.

Treatments also depend on weather. NC State and Texas A&M both say to treat when ants are actively foraging, around 70°F and up, and to keep baits dry ³⁴. Rain or cold can waste a treatment.

Natural enemies help only a little. NC State reports phorid flies cut colony numbers by less than 3%, though they make ants forage less ³.

What drives the cost of fire ant control

We do not give treatment prices for homes here. The drivers are the size of the area treated, how many mounds there are, whether the plan uses broadcast bait, mound treatments or both, and how many visits a year it includes.

Expect ongoing service rather than a single visit. Texas A&M suggests broadcasting bait once or twice a year ⁴, so compare yearly plans, not single visits. Our recurring plan tool compares one-time and ongoing service, and the pest control cost guide explains how quotes are built.

How a fire ant program usually works

1. Check activity. NC State suggests placing a potato chip or hot dog slice near a mound for 5–10 minutes to see if ants are foraging ³.
2. Pick the timing. Treat in late spring and early fall when air is 70–95°F ³, and avoid applying bait within 48 hours of rain ⁴.
3. Broadcast bait. Spread a labeled fire ant bait over the yard, following the label exactly ⁴.
4. Treat problem mounds. Mounds near play areas or doors may get an individual treatment allowed by the label ³.
5. Wait and check. Baits take days to weeks ³⁴. Do not disturb mounds meanwhile.
6. Repeat. Re-treat once or twice a year as new colonies move in ⁴.

Our ant control service page explains what a professional plan includes. Use only products whose labels list fire ants and the site (lawn, garden, pasture).

Living safely with fire ants nearby

• Do not stand on or near mounds, and check the ground before kneeling or sitting ⁵.
• Check items on the ground before lifting them ⁵.
• Wear boots and gloves for yard work in infested areas.
• Walk the yard after heavy rain, when new mounds show up ³.
• Keep fresh bait dry and use it within its shelf life; NC State says 1–3 months for fresh product ³.

Our seasonal pest calendar shows when treatment timing is best.

When to call a professional

Call when mounds are near play areas, doorways or where someone with a sting allergy lives, or when home treatments keep failing.

Call for large properties, pastures or sites under the quarantine, where product choice and rules are more complex ³.

For a severe sting reaction, call 911 first ⁵.

Rules and standards that apply

Federal quarantine (USDA APHIS). The imported fire ant quarantine is in 7 CFR 301.81. It limits moving regulated articles out of quarantined areas to prevent human-assisted spread ¹².

APHIS names nursery stock, hay and soil-moving equipment as high-risk goods ¹, and the regulated-articles rule also covers soil and grass sod ².

The current list of regulated articles is kept on the APHIS site, and an inspector may designate other items near an infestation ².

Recent change. APHIS lists a Federal Register notice, “Domestic Quarantine: Quarantined Areas and Regulated Articles,” published September 11, 2026 (Document 2026-18616) ¹. Boundaries change, so check the current APHIS map.

State rules. States run parallel programs. NC State notes the North Carolina Department of Agriculture restricts moving plant products from infested to non-infested areas and approves specific sod treatments ³.

Pesticide labels (EPA, FIFRA). Use products only as labeled for fire ants and the site. See our pesticide safety guide.

Fire ant vs other yard ants

Common fire ant myths

Myth Pour something on the mound and they are gone.

Reality Treated mounds often move a few feet; the queen must be reached ³.

Myth More bait works better.

Reality Texas A&M says using more than the label amount does not improve results ⁴.

Myth Boiling water is a safe, sure fix.

Reality Texas A&M says it needs caution and often several tries ⁴.

Myth Fire ants are only a summer problem.

Reality They fly and mound in spring and fall too, and mounds pop up after rain ³.

Where fire ants are found

What to do about fire ants in your yard

Your next step depends on where the mounds are. If a few mounds sit far from where people walk, bait in the right weather and watch.

If they are near play areas, doors or anyone with a sting allergy, treat promptly or call a pro. If you plan to move soil, sod or plants across county lines, check the quarantine first.

When comparing services, ask what product is used, whether it is a bait or a contact product, how often the yard is treated and what happens if mounds return. Our guide to choosing a pest control company lists more questions.

Related terms

Pest Bait

A pest bait is a pesticide mixed into a food the target pest wants, so the pest eats it, and for social insects like ants and termites carries it home and shares it with the colony.

Pavement Ant

A pavement ant is a small, dark brown to black ant, Tetramorium immigrans, that nests in soil under sidewalks, driveways and building slabs and comes indoors through cracks to feed on sweets, grease and crumbs.

Carpenter Ant

A carpenter ant is a large ant, in the genus Camponotus, that hollows out wood to build its nest, usually wood that is damp, decayed or soft, but does not eat the wood the way termites do.

Insect Growth Regulator (IGR)

An insect growth regulator (IGR) is an insecticide that disrupts how an insect develops, either by keeping young insects from maturing into breeding adults or by stopping them from building a new outer shell when they molt, rather than killing adults on contact.

Perimeter Pest Treatment

A perimeter pest treatment is an application of a labeled insecticide to the outside of a building, usually the lower foundation wall and the soil or plants right next to it, meant to kill crawling insects before they get inside.

Pesticide Label

A pesticide label is the printed or attached text on a pesticide product, accepted by the EPA at registration, that states what the product contains, how toxic it is, which pests and places it may be used on, how much to apply, and how to store and dispose of it.

Yellowjacket

A yellowjacket is a social wasp in the genus Vespula (and some Dolichovespula) with bold black-and-yellow bands, a narrow waist and a smooth stinger, that lives in a paper nest, often underground or inside a wall.

Seasonal Pest Prevention

Seasonal pest prevention is the practice of timing pest-prevention tasks to the points in the year when each pest becomes active, breeds or moves indoors, so homeowners act just before a problem starts instead of after it shows up.

Also referenced from: Carpenter Ant, Pest Bait