Few summer nuisances are as persistent as a trail of ants marching across the kitchen counter. In Ontario, ant activity climbs through the warm months as colonies forage for food and water — and a handful of scouts can quickly turn into a steady line into your home. Here’s why it happens and how to stop it.
Why Ants Come Indoors in Summer
Ants are most active from late spring through summer, when warm weather pushes colonies to forage aggressively. They come inside for the same reasons any pest does: food and moisture. Sweet spills, crumbs, grease, pet food, and even a dripping tap are all invitations. Once a scout finds a food source, it lays down a scent trail that leads the rest of the colony straight to it — which is why ants often seem to appear all at once.
The Ants You’re Most Likely to See in Ontario
Pavement ants are small and dark, and true to their name they nest under driveways, patios, sidewalks, and building foundations. In summer you’ll often see them crossing hard surfaces carrying food and eggs back to the nest. They’re mostly a nuisance but can forage indoors in large numbers.
Carpenter ants are the large black ants that matter most for your home. They don’t eat wood, but they excavate it to build nests — often in damp or damaged framing — and can cause structural damage over time. Small piles of sawdust-like “frass” are a warning sign.
Pharaoh ants are tiny and yellowish, and they’re a bigger concern indoors: they can contaminate food and spread bacteria, and their colonies “bud” into multiple new nests when disturbed by sprays — which makes DIY treatment backfire.
How to Stop Ants From Getting In
- Wipe up crumbs, spills, and grease promptly, and store food in sealed containers.
- Rinse recyclables and keep garbage bins closed.
- Fix leaks and reduce moisture — ants need water as much as food.
- Seal cracks in foundations and gaps where pipes, wires, and mouldings meet walls.
- Trim branches and plants that touch the house and act as bridges indoors.
Why DIY Sprays Often Make Ant Problems Worse
Reaching for a can of spray feels satisfying, but it usually treats the symptom, not the colony. Sprays kill the visible foragers while the queen and brood stay safe in the nest, so the trail returns within days. With some species, like pharaoh ants, spraying can actually cause the colony to split and spread. Professional treatment uses targeted baits that foragers carry back to the colony, reaching the queen and giving lasting control. For more, see our guides on how long ant treatment takes to work and 5 signs of carpenter ants.
Related Husky services: Ant Control, Common Pest Control, and Year-Round Pest Protection Plan.
Ant Trails Taking Over Your Kitchen?
Husky Pest Control identifies the species, finds the nest, and eliminates ants at the source — with same-day service across Ontario and an 11-month warranty on qualifying indoor treatments.