Fire Ants (Solenopsis invicta) — Identification & Fire Ant Control

Fire ant colonies contain one to many queens and tens of thousands to hundreds of thousands of workers. There are two social forms in North Carolina: single-queen colonies (which defend territory and stay spaced apart, so mound density is lower) and multi-queen colonies (which tolerate neighboring mounds and produce much higher yard-level densities — sometimes hundreds of mounds per acre).

New colonies start in spring and after heavy rains, when queens fly on mating flights, land, shed their wings, and burrow to start a nest. Reproductive potential is extraordinary — a single mated queen can produce a colony of tens of thousands in the first year alone. This is why an unaddressed fire ant problem does not stay small.

• Dome-shaped mounds of loose, granular soil, often 20-60 cm across and 10-25 cm high in Triangle lawns.
• No visible central opening — fire ants enter and exit through side tunnels, unlike most other ant species.
• Aggressive response when disturbed — hundreds of workers boil out within seconds if the mound is kicked or probed. This is the fastest single field ID.
• Preferred locations — sunny open turf, pasture edges, along sidewalks and driveways where soil warms fastest, near hose bibs and irrigation heads.
• Mounds appear or grow rapidly after rain — fire ants use rain to expand mound structure.

If you see a mound with no central hole and workers pour out aggressively when disturbed, treat it as a fire ant mound until identified otherwise.

Fire ant stings are painful. A typical reaction is an immediate burning welt (hence the name), followed within twenty-four hours by a small fluid-filled pustule that can persist for a week and may scar. Most people tolerate limited stings — but there are several groups for whom fire ants are a serious medical concern:

• People with fire ant allergies — stings can trigger anaphylaxis. If a family member has a known ant allergy, active yard control is not optional.
• Young children — small body mass amplifies systemic reactions, and children stumble into mounds routinely.
• Small pets — dogs and cats can be badly stung on the muzzle and paws.
• Elderly and immunocompromised residents — slower to heal, higher secondary infection risk.

Multiple stings, or any sting that causes swelling beyond the sting site, difficulty breathing, or dizziness, is a medical emergency.

Fire ants originated in South America and were introduced to Mobile, Alabama in the 1930s. They have spread steadily north ever since, and North Carolina is at the leading edge of that expansion. The Triangle — South Durham, Cary, Apex, Raleigh, Chapel Hill — sees the highest fire ant pressure in the region. Sunny suburban lawns, warm irrigated turf, open school and park fields, and the mild winters of Zone 7b/8a give them exactly what they need.

Colonies that once died back in cold snaps now overwinter successfully in most Triangle winters. That means fire ant pressure is not going down — properties that were unaffected five years ago are seeing mounds today.

Homeowners searching for how to get rid of fire ants usually try DIY mound treatments first — pouring gasoline, boiling water, or off-the-shelf sprays into a mound. These sometimes kill the visible mound but usually just cause the colony to relocate a few meters away and rebuild. Effective, long-term fire ant control in the Triangle uses a two-step approach that professionals call the Texas Two-Step:

• Broadcast bait treatment across the yard — workers carry the bait back to the queen, eliminating the colony from the inside out. This is the workhorse of fire ant control.
• Individual mound treatment on any visible, high-risk mounds (near play areas, walkways, decks) for fast knockdown.
• Seasonal reapplication — fire ants are a season-long pressure, not a one-and-done treatment.
• Yard risk assessment — flagging entry points, sun-warmed edges, and irrigation-favored zones where mounds are most likely to appear.

Every fire ant treatment for yard use is scoped and priced with a personalized quote based on lot size and current mound density.

• Never disturb an unidentified mound with your bare hands or feet.
• Teach children to identify fire ant mounds and avoid them.
• Keep grass mowed and dense — thick turf makes mound establishment harder.
• Check under mulch, along driveway edges, and near sunny fence lines for early mound development.
• If a family member has known ant allergies, discuss an EpiPen with their physician and start a professional yard treatment plan.
• Do not rely on pouring boiling water or gasoline into mounds — it usually just relocates the colony.
• Report unusually large mound density to your pest professional; multi-queen colonies need adjusted treatment.