Fire Ants in Collin County, TX | Identification and Control
The red imported fire ant (Solenopsis invicta), also called the red ant or mound ant, is the most aggressive ant in Collin County. It builds dome mounds in sunny lawns and along foundations, and a disturbed mound sends hundreds of workers up to sting within seconds. The stings burn, leave a white pustule, and can cause a severe allergic reaction in people with sting allergies. Life-threatening reactions are rare, under 0.1 percent of people stung by US population estimates published by Stafford in the Annals of Allergy, Asthma and Immunology in 1996. Lasting control means reaching the queen.
Found mounds in your yard in Collin County? Our office sits where McKinney, Plano, Frisco and Allen meet, 5 to 10 minutes from most homes in those four cities. Send us a photo or call, and we will tell you what you are dealing with.
Red Imported Fire Ant
An aggressive stinging ant native to South America, established across the southern United States since the 1930s and confirmed in Collin County since the 1990s.
Risk Assessment
Choose a row for the full detail- Color
- Reddish-brown head and midsection, darker almost black abdomen
- Colony size
- 200,000 to 500,000 workers in a mature mound
- Diet
- Omnivorous, eating insects, sweets, oils and seeds
- Queen lifespan
- 2 to 7 years
- Active season
- March through October, with surface activity in mild winters
- Eggs per queen a day
- Up to 800
- Worker size
- 1.6 to 6 mm, mixed sizes in one mound
What Fire Ants Look Like
Reddish-brown front, dark abdomen, and workers of every size in the same mound
Worker fire ants are reddish-brown on the head and midsection with a darker, almost black abdomen. They are not uniform in size. A single mound holds workers from 1.6 mm to 6 mm, and that mixed-size lineup is the easiest tell, because most other ants in Collin County pick one size and stick with it.
The body has a pinched two-segment waist that rules out most ants found indoors here. The antennae have ten segments ending in a two-segment club, and the midsection is smooth with no spines. The Texas A&M AgriLife fire ant identification guide uses the same features.
How to identify a fire ant from above, by its reddish-brown front, dark abdomen, two-segment waist and clubbed antennae
- Reddish-brown head and midsection with a darker abdomen
- Mixed sizes inside the same colony, 1.6 to 6 mm
- Two-segment pinched waist
- Ten-segment antennae with a two-segment club
- No spines on the midsection
- A dome mound with no visible central opening from above
- Workers swarm out to sting within seconds of the mound being disturbed
Other Names for Fire Ants
Fire ant and red ant mean the same insect around Collin County, the red imported fire ant. The fire in the name comes from the sting, an alkaloid venom that burns right away, and the burning is what people remember. Smaller workers can look noticeably darker than larger ones, so a mound of brown or dark ants can still be fire ants. The mixed sizes and the dome mound are more reliable than color.
Where Are Fire Ants Found?
Fire ants are found across the southern United States. The species came from South America, has been established in the South since the 1930s, and has been confirmed in Collin County since the 1990s. It is widespread here. The clay-heavy soil holds the moisture and warmth that help queens survive winter and expand mounds fast in spring.
| Name | What it means |
|---|---|
| Red imported fire ant | The formal name for Solenopsis invicta, the ant most people mean when they say fire ant. |
| Red ant | The informal name most homeowners use, from the ant’s color. Some older pest guides use it for several reddish ants, so fire ant is the more exact label. |
| Mound ant | Named for the dome-shaped mound with no central opening, the best field sign of all. |
| Native fire ant | A different Texas species, Solenopsis xyloni, rarely seen in suburban Collin County. The imported fire ant has outcompeted it across nearly all residential property, so a fire ant in McKinney, Allen, Frisco or Plano is the imported one. |
How to Tell Fire Ants from Other Ants in Collin County
Four ants are regularly mistaken for fire ants or found in the same yard. Color, size pattern, mound shape and the response to a disturbed nest separate them without a microscope.
| Species | Size | Key Feature | Nesting Habit |
|---|---|---|---|
|
Fire Ant
AKA: Red Ant, Mound Ant
Solenopsis invicta
This species
|
1.6 to 6 mm. Mixed sizes within a single colony is the fastest tell. No other common Collin County ant runs this size range in one mound. | Reddish-brown head and midsection with a darker rear section. Workers sting as a group within 10 to 15 seconds of any mound disturbance. The sting burns at once and leaves a white pustule within 24 hours. | Dome-shaped mound with no visible central opening from above. The mound feels fluffy and loose after rain. Most active at foundation edges, irrigation zones and sunny open lawn. |
Carpenter Ant
AKA: Big Black Ant, Large Black Ant
Camponotus spp.
|
6 to 13 mm. All black or red and black. Every worker is larger than the largest fire ant worker. | No sting, bites with its jaws only. Slow single-file movement, usually after dark. No visible outdoor mound. | Nest tunnels run along wood grain. Look for coarse wood shavings mixed with insect parts near door frames, window sills or roof trim. |
Odorous House Ant
AKA: Sugar Ant, Stink Ant
Tapinoma sessile
|
2.4 to 3.3 mm. Dark brown to black and all one size, with no size variation across the colony. | One-node waist, where the fire ant has two. Crushed workers smell like blue cheese or rotten coconut. Hunts for food in kitchens and pantries and has no real sting. | No outdoor mound. Nests in wall voids, under insulation and in mulch beds, and enters through the smallest gaps in door sweeps and window frames. |
Pavement Ant
AKA: Sugar Ant, Sweet Ant
Tetramorium immigrans
|
2.5 to 3 mm. Dark brown to black and all one size, with none of the fire ant’s reddish-brown coloring. | Parallel grooves run lengthwise on the head and midsection, visible under magnification. Two-node waist. Can give a weak sting but rarely defends itself and never attacks as a group. | Nests in soil under slabs, sidewalks and driveways, pushing sandy soil up through cracks into small cone-shaped piles. |
Tawny Crazy Ant
AKA: Raspberry Crazy Ant, Hairy Crazy Ant
Nylanderia fulva
|
2 to 3 mm. Reddish-brown, the closest color to the fire ant in this table. All one size, with long legs and long antennae for its body. | Fast, erratic movement with no organized trails. No working sting and no group defense when disturbed. | No central mound. Nests loosely under leaf litter, rotting wood and ground debris. Not established in Collin County, though workers sometimes arrive on landscaping plants or moving cargo from Houston, Austin and the Coastal Bend. |
Fire Ants vs Tawny Crazy Ants
The Fire Ant in Three Numbers
1 to 2 days
The Texas A&M fire ant project says a fire ant sting burns, itches and forms a white pustule in a day or two.
Texas A&M AgriLife fire ant project, Medical Information
Under 0.1%
US population estimates published by Stafford in the Annals of Allergy, Asthma and Immunology in 1996 put life-threatening allergic reactions to fire ant stings at under 0.1 percent of people stung.
Stafford, Annals of Allergy, Asthma and Immunology, 1996
About 1 in 3
NC State Extension says roughly 1 in 3 people living where fire ants are established are stung each year, and about 2 percent of those stings bring a body-wide allergic reaction.
NC State Extension
Are Fire Ants Poisonous or Dangerous?
Yes, fire ants are dangerous, mainly because of how they sting. The venom is mostly solenopsin, a piperidine alkaloid, combined with allergenic proteins. Nearly everyone stung gets a burning welt that turns into a pustule. Body-wide reactions such as widespread hives, swelling beyond the sting area or stomach upset occur in an estimated 0.5 to 2 percent of people stung. Life-threatening anaphylaxis is rarer, with U.S. population estimates below 0.1 percent of people stung (Stafford, Annals of Allergy, Asthma and Immunology, 1996). NC State Extension says roughly 1 in 3 people living where fire ants are established are stung each year.
Do Fire Ants Bite or Sting?
Fire ants do both. Each worker bites with its jaws to anchor itself, then pivots to sting several times from its rear. Vibration at the surface brings workers up within 10 to 15 seconds, and the first ant to sting releases an alarm scent that sends the rest in together. That is why most people are stung several times before they feel the first one, and why brushing them off your ankle does not work. Walk away from the mound at once, then take off shoes and socks somewhere safe.
The burning peaks in the first few minutes. Within 24 hours an itchy white pustule forms over the site and can last seven to ten days. Wash with soap and water, use a cool compress, and take an over-the-counter antihistamine or hydrocortisone cream if the itching is bad. Do not break or scratch the pustule, because the University of California notes it can become infected if not kept clean and may leave a lasting scar. Bee-sting remedies such as baking soda paste give less relief, because the venom chemistry is different. Texas A&M fire ant sting medical guidance covers first aid and when to seek emergency care.
Get emergency care for trouble breathing, a swelling throat or tongue, hives spreading beyond the sting site, dizziness, a racing heartbeat, nausea or fainting. These are signs of a body-wide allergic reaction. If you have been prescribed an EpiPen for insect sting allergies, it remains the first response to any anaphylactic reaction. Children, older adults, people with known sting allergies and anyone with a heart condition are at higher risk.
Fire ant sensitivity can also heighten the reaction to a striped bark scorpion sting, a cross-reaction confirmed by published fire ant and scorpion venom allergy research. The CDC fire ant hazard guidance for outdoor workers covers practical precautions for people with known sting allergies.
How Bad Is Your Fire Ant Problem?
The question is whether you have one mound or a multiple-queen colony spreading across your yard and your neighbors. Oklahoma State fire ant colony assessment guidance covers how to tell the colony types apart in the field. These are the signals that change the answer.
Multiple Mounds Within 20 Feet
Three or more mounds in the same part of the yard usually means a multiple-queen colony. A single mound can be spot-treated. A multiple-queen colony needs bait spread across the whole yard.
A Sting on the Property
A sting involving a child, an older family member, a pet or someone with sting allergies raises the priority at once. A colony in a play area is a medical risk, not just a yard problem.
Mounds Within 10 Feet of the Foundation
Mounds beside the foundation can drive workers indoors during drought or flooding. Treatment becomes time-sensitive when children, pets or older family members use that part of the yard.
Mounds Back Within Weeks of a DIY Treatment
If mounds reappear in the same yard within 3 to 6 weeks, the queen survived. Surface treatments rarely reach her, so a yard-wide bait is the next step.
Where Fire Ants Build Mounds
Mounds appear most often where soil meets concrete, along foundations, driveway edges, slab corners and pool decking. Workers come and go through underground tunnels that surface several inches from the visible mound, which is why treating the mound alone often misses the queen. Fire ants also move into air conditioner condensers, irrigation control boxes and pool pump housings, where they cause shorts, and the first sign is often equipment that stops working before anyone sees the colony. They come indoors rarely, mostly during long droughts or after flooding.
Fire Ant Pressure Across Collin County
Pest Me Off service records show 312 fire ant calls across Collin County in 2025, and 78 percent of them involved multi-mound, multiple-queen colonies. Pressure runs highest in neighborhoods with continuous green space across property lines, and Stonebridge Ranch, Craig Ranch and Windsong Ranch consistently produce the most calls. Pressure is also consistently high in Allen, Frisco, Plano and Prosper.
New construction grading in Anna (Liberty Hills, Sherley Farms), McKinney (Trinity Falls) and Lucas (Inspiration) keeps breaking up existing mounds, which splits single colonies into several satellite mounds. Creek corridors like Slayter Creek work as migration paths in dry summer stretches.
Mound activity peaks in late spring and again in early fall, with a short slowdown in the hottest weeks of summer. Mating flights follow the warm rains of March through May, and new mounds appear within 24 to 48 hours of heavy rain. Foraging slows below 60 F and nearly stops below 50 F, but surface activity carries on through mild winters.
Pattern from Texas A&M AgriLife Fire Ant Project monitoring data and Pest Me Off service call records across Collin County, 2023 to 2026.
How Fire Ant Colonies Spread
How Pest Me Off Treats Fire Ant Colonies
Ant-Nihilation is our ant program. It pairs a bait spread across the yard to reach the queen with a perimeter barrier we call the Scorched Earth Barrier. If the queen survives, the colony rebuilds within weeks, and Texas A&M fire ant research on the two-step method has documented that failure in single-mound treatments since the 1990s.
Property Assessment
Walk the whole property to map active mounds, find colonies beside the foundation, and check irrigation zones and equipment housings. Count the mound clusters to tell a single-queen colony from a multiple-queen one.
Yard-Wide Bait Application
Spread a non-repellent bait across the whole treated area. Workers walk through it without noticing and carry it back to the queen and the young ants, and mound activity collapses over 1 to 2 weeks. It also reaches satellite colonies that have not built a visible mound yet.
Direct Mound Treatment
Treat each active mound directly to speed up the collapse, which matters most where one established mound has not yet spread across the yard.
Scorched Earth Barrier
Apply a non-repellent product around the foundation, along irrigation lines and at the property edges. Scout workers from neighboring yards cross it before they reach open lawn and carry it back to their own colony. The barrier is reapplied every quarter.
& Other Companies
How to Get Rid of Fire Ants Yourself
Once a colony is established, a bait that reaches the queen is the only reliable way out. These steps make that bait work and make your yard less inviting to scouts from next door.
Why Some DIY Responses Fail for Fire Ants
Most failed attempts go after the visible mound with something from the garage or a tip from a video. Each of the mistakes below kills surface workers and leaves the queen alive to rebuild.
Boiling Water or Gasoline
Boiling water reaches only the top few inches of the colony, and the queen sits much deeper. Gasoline is dangerous, contaminates soil, does not reliably reach the queen, and is illegal under Texas pesticide use law.
Repellent Sprays, Dusts and Spot Treatment
Repellent sprays and diatomaceous earth kill surface workers and signal the colony to move. In a multiple-queen colony one mound is connected underground to others, so treating one alerts the rest and one mound becomes three or four.
Grits, Vinegar and Cornmeal
Popular internet remedies with no basis in insect science. Fire ants do not die from eating grits and are not harmed by vinegar or club soda. These waste time while the colony grows.
Ignoring the Yards Next Door
Even a perfect yard-wide treatment cannot stop scouts from an untreated neighboring yard, which cross property lines within six weeks. Without a perimeter barrier the cycle restarts every season.
Common Fire Ant Questions
What is the difference between a fire ant and a red ant?
How long does a fire ant sting last?
Are fire ants dangerous to dogs?
Will fire ant treatment harm my pets or kids?
What time of year should I start fire ant treatment?
Do fire ant baits work in winter?
Can fire ants from a neighbor’s untreated yard keep coming back onto my property?
Can you treat some fire ant mounds yourself and have a professional handle the rest?
Is there a permanent way to get rid of fire ants in Collin County?
How do I get rid of fire ants in my yard?
Fire Ants in Your Yard. We Go After the Queen.
We spread bait across the whole yard, treat every active mound directly, and keep the Scorched Earth Barrier up against the yards next door. McKinney, Allen, Frisco, Plano, and all of Collin County.