By Camille Landry, M.S. Entomology
Fall in Southeast Texas doesn’t always arrive with crisp mornings and colorful leaves. Sometimes, it arrives with ants.
As temperatures begin to change and we finally get some relief from the intense summer heat, homeowners around Cleveland and throughout Southeast Texas often notice an increase in ant activity. Suddenly there are new fire ant mounds in the yard, trails of tiny ants around the house, or thousands of fast-moving crazy ants seemingly appearing overnight.
It can feel like the ants suddenly multiplied.
In reality, many of those colonies have been there all along.
In our area of Texas, we deal with a wide variety of ant species, including ghost ants, pharaoh ants, carpenter ants, fire ants, and crazy ants. While homeowners may simply see “ants,” each of these species can behave very differently. They have different colony structures, nesting preferences, foraging patterns, and invasion habits. Some establish colonies inside structures, while others primarily live outdoors and enter homes searching for food, water, or shelter. That’s why proper identification is so important—when it comes to ants, there is no one-size-fits-all approach to control.
Why ants become so noticeable in the fall
Ant activity is closely tied to temperature, moisture and food availability. During periods of extreme heat and drought, some ants become less visible. Fire ants, for example, can move deeper into the soil where conditions are cooler and moisture is available.
Then we get a good rain.
Almost overnight, fire ant mounds seem to pop up everywhere. The rain didn’t necessarily create more fire ants—it simply changed where the colony was located and made its activity much easier to see.
Texas A&M AgriLife notes that fire ants are particularly active during spring and fall and that colonies readily move, especially following rainfall.
That makes fall one of the most important times of year to pay attention to what’s happening in your yard.
Fire ants: The fall comeback
Most Texans don’t need an introduction to fire ants.
Their mounds are common in lawns, pastures, parks, playgrounds and along roadsides throughout our area. What homeowners sometimes don’t realize is that the mound we see above ground represents only part of a much larger colony below the surface.
Fire ants can also move from neighboring properties, which is why controlling a few visible mounds doesn’t necessarily solve the larger problem.
Fall is actually an excellent time for fire ant management. Texas A&M’s fire ant program identifies late August through October as an ideal period for applying many bait-formulated fire ant products. Because some baits work gradually, fall treatment can reduce populations going into winter and result in fewer mounds the following spring.
In other words, what you do about fire ants this fall can affect what you see next spring.
Crazy ants are a different kind of problem
Then there are the ants that make people ask us, “What in the world are these?”
Tawny crazy ants have become an increasingly familiar pest in Southeast Texas.
Unlike fire ants, tawny crazy ants don’t typically create the obvious centralized mound most homeowners expect from an ant colony. They can nest beneath landscape materials, rocks, timber, debris, potted plants, concrete and other objects that retain moisture.
And there can be an incredible number of them.
Texas A&M reports that tawny crazy ant populations increase dramatically during the summer and can remain high through October and November. They have become established across numerous Texas counties, including Liberty and Montgomery counties in our region.
Their name describes them well. Rather than traveling in the neat, organized trails we associate with many ants, workers often move quickly and erratically.
These ants can become more than a simple nuisance. Heavy infestations have been associated with electrical equipment, and colonies can occur around homes, businesses and landscapes.
Crazy ants also require a different management approach than many common household ants. Simply spraying the ants you see indoors is unlikely to address colonies primarily located outside. Correct identification becomes especially important before deciding how an infestation should be managed.
Why are ants coming inside?
When weather conditions change outdoors, ants adjust.
They are constantly looking for the same basic resources we are: food, water and a comfortable place to live.
Small plumbing leaks, air-conditioning condensation, pet food, crumbs, sugary spills, mulch against the foundation and excessive landscape moisture can all help create favorable conditions.
As cooler weather approaches, homes can also provide a more stable environment. Texas A&M AgriLife specialists note that insects and other arthropods may move indoors during drought or cooler weather while searching for water or more favorable conditions.
That trail of ants across the kitchen counter isn’t the real problem. It’s a clue.
The important question is: Where are they coming from and why are they there?
Don’t just treat the ant—look for the source
One of the biggest mistakes I see in pest control is focusing only on the insect we can see.
Successful ant management starts with identification.
Is it a fire ant? Tawny crazy ant? Carpenter ant? Argentine ant? Ghost ant? Or another one of the many ant species found in Texas?
Different ants behave differently, nest differently and respond differently to control methods.
Homeowners can also make their property less attractive to ants by correcting moisture problems, repairing leaks, reducing unnecessary debris around the home, keeping vegetation away from the structure, properly storing food and pet food, and sealing potential entry points.
For crazy ants specifically, reducing harborage such as leaf litter, fallen limbs and objects sitting on the soil—and correcting excess moisture and drainage issues—can be important parts of an integrated management approach.
A little fall advice from an entomologist
If you suddenly notice more ants this fall, don’t panic—and don’t assume they’re all the same.
Take a closer look.
Notice where they’re traveling. Look for moisture. Check around landscaping, utility boxes, foundations and irrigation. Pay attention after rainfall. And if you’re dealing with an unusually large infestation, identifying the species should come before deciding how to treat it.
In Southeast Texas, we don’t really have a “pest-free” season.
We simply have different pests taking their turn.
And this fall, don’t be surprised if the ants come marching in.
Camille Landry holds a Master of Science in Entomology and is co-owner of FullScope Pest Control, serving Cleveland and communities throughout Southeast Texas. She has worked in the pest management industry for more than two decades and focuses on science-based pest education, prevention and source-first pest management.