Fire Ants in Bexar County TX: How to Protect Your Yard and Family

Fire ants entered the country through Mobile, Alabama in the 1930s and spread through the South and Southwest. Texas is one of the most heavily infested states. They thrive in open, sunny ground (lawns, sports fields, pastures) which makes Bexar County's St. Augustine and Bermuda grass neighborhoods exactly the habitat they want.

A single fire ant colony can contain 100,000 to 500,000 workers and multiple queens in polygyne (multi-queen) colonies, which are now the dominant form in Texas. Polygyne colonies are harder to eliminate because the colony can replace a dead queen quickly and colonies will relocate rather than defend a single mound, making individual mound treatment less effective than broadcast baiting.

Texas A&M AgriLife Extension developed and validates the Two-Step Method as the most cost-effective fire ant management approach for homeowners. Step one is a broadcast bait application distributed across the entire lawn and landscape area in spring and fall, when fire ants are most actively foraging. Bait is carried back to the colony by worker ants and affects the queen, causing population collapse over weeks.

Step two is individual mound treatment for any mounds that remain or are discovered after the initial bait broadcast. Mound drenches, granular contact products, or desiccating dusts are used for this step. The combination approach takes advantage of bait's systemic effect while providing faster knockdown for mounds in high-use areas like playgrounds or near entry doors.

Children under three and elderly adults are at highest risk of severe reactions to fire ant stings. Fire ants swarm and sting simultaneously when a mound is disturbed, which makes accidental contact particularly dangerous for those who cannot move away quickly. Inspect play areas, sandbox surrounds, and lawn areas near fences before allowing children to play in them.

Pets, particularly dogs that investigate mounds with their noses, are at risk of facial and airway stings. Dogs have been killed by fire ant swarms in Texas, particularly when restrained on a tie-out over or near a mound. Check tie-out areas and pet runs regularly, especially after rain, which prompts colonies to rebuild surface mounds.

Move the person away from the mound immediately and brush off any ants that remain on the skin. Wash the sting sites with soap and water. Apply a cold compress to reduce swelling and pain. White pustules that form at sting sites within 24 hours are normal and should not be popped, as rupture increases the risk of secondary bacterial infection.

Call 911 or go to an emergency room immediately if the person stung shows signs of a severe allergic reaction (anaphylaxis): hives spreading beyond the sting site, difficulty breathing, swelling of the throat or tongue, rapid pulse, or dizziness. People with known severe insect sting allergies should carry an epinephrine auto-injector and wear a medical alert identification.

Homeowners can effectively manage moderate fire ant pressure using the two-step method with products available at Texas lawn and garden retailers. Professional pest control becomes warranted when mound density is high across the entire property, when previous DIY treatments have failed, or when the property includes areas inaccessible to broadcast spreaders such as dense groundcover or landscaped beds.

Commercial properties, schools, and recreational facilities in San Antonio are generally better served by professional programs that include monitoring, documentation, and reapplication schedules. Texas A&M AgriLife Extension recommends that anyone caring for an area where vulnerable populations gather treat fire ant management as a routine maintenance item, not an occasional response.