How Do Professional Pest Controllers Deal With an Ant Colony?

The Survey Comes First

Finding the nest, or at least the route to it, changes everything. The technician follows the trails outwards — through the entry point, along the base of the wall, across the paving — to establish where the colony actually is.

That also determines what you have. Black garden ants nesting outside are one job; pharaoh ants nesting in a warm building void are a different one, and treating the second like the first makes it considerably worse.

Trophallaxis: Why the Method Works

Ants feed each other mouth to mouth, passing food through the colony. A forager that takes gel bait carries it home and distributes it to workers that never leave the nest, then to the brood and eventually to the queen.

That is the mechanism, and it is the only practical way to reach a queen who is underground and never comes out. It is also why the bait has to be slow-acting: anything that killed on contact would stop at the first ant and never travel.

Why the Trail Is Left Alone

Because the trail is the delivery route. Spraying it, cleaning it or moving the bait breaks the mechanism, which is why we ask people not to tidy up during treatment and why a customer who has been spraying for a fortnight has made the job harder rather than easier.

It also means an effective treatment looks wrong for the first day or two. More ants at the bait, not fewer, is a sign it is working.

Placement, Not Volume

Bait goes on the trail and at the entry points, in small quantities, out of reach of children and pets, and in more than one formulation where the colony’s preference is unclear — ants want protein at some points in the season and sugars at others.

Where the nest itself is accessible, it can be treated directly. Where it is under a patio or a solid floor, the bait route is the only realistic option, which is why finding the trail matters more than finding the nest.

What You Should See, and When

Days one and two: heavy activity at the bait. Days three to seven: activity falling away as the colony declines. Beyond that: nothing, or a sharply reduced trickle that stops.

If a strong trail is still running after ten days, tell us — it usually means a second colony rather than a failed treatment, and that is worth knowing. Ant treatment is £190 for a flat and £220 for a house. Once it is finished, wash the whole run with hot soapy water so nothing follows the old trail next summer.