Odorous house ants

What odorous house ants look like

The quickest way to confirm an odorous house ant is to crush one. It gives off a sweet smell that most people describe as coconut, or coconut that has gone off. No other small house ant in Ontario smells quite like it. The workers are about 3 mm long, dark brown to black, and all one size. The body is smooth and slightly greasy looking, with no spines on the back. The node on the waist is flattened and hidden under the abdomen, so from the side the ant appears to have no waist bump at all. They walk in slow, steady trails, unlike crazy ants, which dart in all directions, and acrobat ants, which lift a heart-shaped abdomen over their back.

Signs you have odorous house ants

• The coconut smell. Crushed workers give off a sweet, slightly sour coconut odour. This is the single best confirmation.
• Trails to sweet food. Steady lines of ants running to syrup, pet food, spilled juice, fruit or the recycling bin.
• Activity after rain. Numbers indoors jump sharply after heavy rain or a long dry spell, when outdoor nests are disturbed.
• Ants along edges. Trails follow counter edges, pipes, window frames and the line where the wall meets the floor.
• Several trails at once. These colonies have many queens and many satellite nests, so you often see separate trails in different rooms.

Why odorous house ants come indoors

Outdoors they nest in soil, under stones, patio slabs, mulch and firewood, and they live mainly on honeydew from aphids on shrubs and trees. When that honeydew supply is cut off by rain, drought or cold, they look for sugar elsewhere, and a kitchen is the nearest source. Once inside, they will nest in wall voids, under floors, behind insulation and around warm pipes, especially where there is a small moisture leak. Because the colony splits easily into satellite nests, part of it can live outdoors while another part lives in your wall. That is why spraying a visible trail rarely ends the problem. It kills the foragers you can see and often pushes the rest of the colony to split further.

How to keep odorous house ants out

• Seal gaps around door frames, window frames, dryer vents and pipe entries with caulk or foam backed by sealant.
• Keep mulch, soil and firewood back from the foundation and pull ground cover away from siding.
• Trim branches and shrubs so they do not touch the roof or walls, since aphid-covered branches act as a bridge.
• Clean up sugar quickly. Wipe counters, rinse recyclables, store syrup and honey in sealed containers and lift pet bowls between meals.
• Fix slow leaks under sinks and in crawl spaces, and correct grading or downspouts that keep soil wet against the house.

How GO! Pest Control treats odorous house ants

• Inspection. We follow the trails back to their entry points, check the foundation, mulch beds and shrubs for the outdoor nest, and look for damp areas inside that could hold a satellite nest.
• Treatment. We use slow-acting sweet baits that foragers carry back to the queens, combined with a targeted exterior treatment at entry points. We avoid broad indoor spraying, which scatters these colonies.
• Follow-up. We check bait uptake and trail activity on a return visit and adjust the bait or placement if the ants have switched food preference.
• Advice. We show you the gaps, branches and moisture problems that let them in, so the same trail does not come back next season.

We are licensed, insured and bonded, and we work in homes, apartments, condos and businesses across the Toronto GTA, Ottawa and Hamilton.

Common questions about odorous house ants