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Argentine Ants: Why They Take Over (and How to Stop Them)
The tiny brown ants that march across Fresno kitchens are almost always Argentine ants — here is how to identify them, why spraying makes them worse, and how to actually get rid of them.
Argentine ants are tiny, uniform light-brown ants that form enormous multi-queen supercolonies — and they are the number-one nuisance ant in Fresno and the rest of the Central Valley. If you have a thin trail of small brown ants marching across a counter or along a baseboard, these are almost certainly what you are looking at. The catch is that the colony you need to kill is almost never the trail you can see.
An Argentine-ant trail along a kitchen counter. These foragers are a fraction of a colony nested elsewhere.
How to identify an Argentine ant
Argentine ants are about 3mm long, an even light-to-medium brown, with a single node at the waist and no spines. The quickest tell is what they do not do: unlike odorous house ants, they give off no smell when crushed. They move in fast, well-organized trails and recruit heavily to any food or water source.
Why Argentine ants are so hard to get rid of
Most ant species keep one queen and one nest. Argentine ants do the opposite: a single supercolony can hold hundreds of queens spread across many interconnected nests, stretching across yards and whole blocks. Workers move freely between nests, so wiping out the ants at one spot does nothing to the colony as a whole — the population just refills the trail.
Hitting an Argentine-ant trail with a repellent spray feels effective because the foragers die on contact. But the repellent signals the colony to split and relocate — a process called budding — turning one nest into several. With this species, spraying the trail reliably makes the problem bigger. Bait, do not spray.
Why they come inside
Argentine ants come indoors hunting two things: water and sweets. Fresno’s long, hot, dry summers push them toward moisture — sinks, drains, pet bowls — while sugary residue and spills draw them to the kitchen. They slip in through tiny gaps around windows, doors, pipes, and slab edges, and once a forager finds food it lays a chemical trail for the rest to follow.
How to get rid of Argentine ants
1. Don’t spray the trail. Repellent spray causes budding and more colonies. The trail is your map to where they get in — leave it intact until the bait is working.
2. Put down slow-acting bait. Place sweet (sugar-based) gel or liquid bait along the trail and at entry points. Foragers carry it back and feed the queens, which is what actually kills the colony. Seeing more ants at the bait at first is a good sign.
3. Erase the trail, then seal. Once the bait is working, wipe trails with soapy water to remove the pheromone, clean up food and standing water, and caulk the gaps where they enter.
4. Treat the outside. Because the nests are outdoors, trim vegetation off the house, move mulch and firewood away from the foundation, and address the perimeter where they cross in.
Our full guide to getting rid of ants walks through the baiting approach step by step.
When to call a pro
DIY baiting clears a lot of ordinary trails. It tends to fail against an established supercolony that refills every season, ants pouring from a wall void or under a slab, or several trails at once. A professional uses non-repellent products the ants cannot detect — so they walk through and carry it back instead of avoiding it — plus an exterior barrier and planned follow-up, because supercolonies are persistent. Our ant control service targets the nest, not the trail.
See our ant control process →Argentine ant FAQ
What are the tiny brown ants in my kitchen?
In Fresno, tiny uniform-brown trailing ants are almost always Argentine ants. They nest outdoors in large supercolonies and come inside for water and sweets, which is why they keep returning if the nest is never reached.
Why did spraying make my ant problem worse?
With Argentine ants, repellent spray causes the colony to split and relocate — a process called budding — so one nest becomes several. Baiting, not spraying, is what actually works on them.
Do Argentine ants bite or sting?
No. Argentine ants have no meaningful bite or sting and are not dangerous — they are a nuisance and a food-contamination problem rather than a health threat.
Where are Argentine ants found in the US?
They are an invasive species established across California and much of the warm southern and coastal United States. They are especially abundant in the Central Valley, where supercolonies can span entire neighborhoods.
How do I get rid of Argentine ants for good?
Bait the colony rather than spraying the trail, seal entry points, and treat the exterior perimeter. Established supercolonies usually need professional non-repellent treatment and follow-up to stop the seasonal return.
Argentine ants back again? We’ll treat the colony, not the trail.
Call (559) 472-8200 or request a no-cost inspection — non-repellent treatment and a perimeter barrier built for Fresno’s supercolonies.