The trail is your delivery system
An indoor ant trail is a pheromone road between a nest and a food source. Cleaning it away removes your best chance of reaching the nest — the workers simply rebuild the route somewhere less convenient.
Leave the trail intact and place bait directly on it. Workers pick the gel up, carry it back and feed it to the brood and the queen, which is the only way the nest actually dies.
Identify the species you have
Black garden ants (Lasius niger) nest outdoors and forage indoors for sugars, usually in summer. Pharaoh ants are tiny, pale yellow-brown, nest indoors in warm voids, and split their colonies when disturbed by spray — which is why they need baiting, never spraying.
Placement and dosage
Apply small dots (a rice-grain to pea-sized amount) directly on the trail, at entry points and near the nest side of the run rather than at the food end.
Everything below assumes a professional-strength bait — our ant killer gel kits ship with the applicator and placement map referenced here.
- On the trail itself, 2–3 dots per metre of active run.
- At the point ants enter — a door threshold, airbrick, window frame or pipe gap.
- Behind the kickboard and under the sink where trails often disappear.
- On a piece of card or foil in food-prep areas so the surface stays clean.
Timings and top-ups
Expect heavy recruitment for the first 24 hours — that is bait moving into the nest. Trails usually thin out within 24 to 36 hours and disappear inside 3 to 7 days. Replace any dot that has been fully consumed within 48 hours so the flow keeps reaching the brood.