Fall Ant Season Arrives in Southeast Texas as Fire Ants and Tawny Crazy Ants Reappear

The phone calls in Liberty County trail the weather by about a week. A stretch of late-summer heat, then a front, then rain, and the next thing Cleveland-area homeowners know there are fire ant mounds along the driveway that were invisible in August.

Camille Landry has been fielding those calls for more than two decades. She holds a master's degree in entomology and co-owns FullScope Pest Control, which serves Cleveland and communities across Southeast Texas, and she wrote about the pattern this week for Bluebonnet News.

Her first point is the one homeowners tend to resist. The ants were already there.

Through the worst of the summer heat and drought, fire ant colonies work deeper into the soil, where it is cooler and where the moisture sits. A good rain does not add colonies. It changes where the colony can be seen. Mounds push up, foragers spread out, and a lawn that looked clean in July looks infested by the first week of October. Texas A&M AgriLife's fire ant program makes the same observation from the research side: fire ants are most active in spring and fall, and colonies relocate readily after rainfall.

That shift in activity is worth real money to anyone who treats turf. Late August through early October is the window AgriLife's fire ant project calls ideal for bait application, for reasons that have less to do with the ants than with the calendar. Baits work slowly, taking weeks to months to cut mound numbers, and fall weather is more predictable than spring weather — a treatment applied when no rain is expected for several days gets the time it needs to be picked up and carried down into the colony. For heavily infested turf, AgriLife recommends the two-step method: broadcast bait across the whole property, then treat the individual mounds that persist.

There is a neighborhood problem baked into all of it. Fire ants move between adjoining yards constantly, so one treated lot bordered by untreated ones tends to refill from the fence line inward. AgriLife's guidance is blunt about the remedy — coordinate with neighbors and treat at the same time.

The ants homeowners cannot easily coordinate around are tawny crazy ants. They build no tidy dome to scan for. They nest under rocks, timber, landscape debris, potted plants and slabs, anywhere that holds moisture, and they do not travel in organized trails. Individual workers move fast and erratically, which is where the name comes from.

AgriLife Extension counts 43 Texas counties inside the tawny crazy ant's range since the species surfaced in Harris County in 2002, along with confirmed populations in Louisiana, Mississippi, Alabama, Georgia and Florida. Numbers build through the summer and typically stay high into November. Heavy infestations have been associated with electrical equipment, a detail that matters to anyone with an outdoor condenser, a well pump or a pool panel. Because the colonies live outside the structure, spraying the ants that turn up indoors rarely touches the source.

That distinction runs through Landry's advice. Fire ants, carpenter ants, ghost ants, pharaoh ants and Argentine ants all respond differently to different materials, and a wrong identification wastes both the treatment and the customer's money. When ants start showing up inside as the weather turns, the line across the kitchen counter is a symptom, not the problem. The questions worth answering are where the ants are coming from and what is drawing them in — a slow plumbing leak, air-conditioning condensate, pet food left down, mulch piled against the slab, or a landscape that never dries out.

Fix those and the fall surge shrinks on its own. Southeast Texas does not truly have a pest-free season. It has pests taking turns, and right now the calendar belongs to the ants.