Why fire ant mounds keep returning to San Antonio yards after you treat them, and the two-step approach that controls colonies instead of just moving them.
By Time's Up Pest Control. Published 2026-10-22.
You pour something on the mound, the ants disappear, and a week later there's a new mound three feet away. If that sounds familiar, you're not alone. Red imported fire ants are one of the most common pest complaints in San Antonio, and they're hard to beat with mound-by-mound treatment.
The visible mound is only the top of the colony. The queens, eggs and most of the workers can be deep underground. Contact sprays and drenches kill the ants they touch, and the survivors move the queen and build a new mound nearby.
Multiple-queen colonies can split and spread across a yard, leaving many small mounds close together. Killing one queen doesn't end the problem.
Winged fire ants mate and fly in to start new colonies, especially after spring and summer rains. Even a fully treated yard can be recolonized from untreated land nearby.
Fire ants move up in the soil after rain or heavy irrigation, so mounds can seem to appear overnight. For more on that, see pest control after rain and flooding.
Texas A&M AgriLife Extension recommends a two-step approach for yards with recurring fire ants:
Bait works best when the ground is dry and ants are foraging, often in the morning or evening on warm days. Rain soon after you spread it can make it less effective. Fresh bait matters too, because ants won't pick up stale product.
Call for help if mounds keep returning, ants are getting into the house or into electrical boxes and AC units, or anyone in the home is allergic to stings. Professional treatments can last longer than store-bought products and cover the whole property, not just the mounds you can see.
Time's Up Pest Control treats fire ants and other ants across San Antonio as part of our pest control services and seasonal prevention plans. Our licensed technicians are local and family-owned, and we offer free estimates.
Contact treatments kill the workers they touch but often miss the queens deep in the colony. The survivors move the queen and rebuild nearby.
Spring and early fall are the most effective, on dry days when ants are actively foraging.
Most people get painful, itchy pustules. People with sting allergies can have serious reactions and should get medical care right away.
Time's Up Pest Control is a family-owned San Antonio pest control company serving homes and businesses. Licensed technicians (TPCL #877175), free estimates, satisfaction guarantee and 24/7 emergency service.
Phone: (210) 868-2267
Email: info@timesupbugs.com
Address: 1800 NE Interstate 410 Loop, Suite 216-B, San Antonio, TX 78209
Services: Pest Control, Termite Control, Pest Prevention, Commercial Pest Control