Odorous House Ant (Tapinoma sessile)

How to Identify Them

Workers are small and dark, all about the same size, with a single flattened node hidden under the abdomen. The quickest test is to crush one and smell it. They move quickly and erratically when disturbed and often raise their abdomens.

Common look-alikes:

• Ghost ant: same smell, but with a pale see-through abdomen.
• Argentine ant: similar size and color, but only a faint musty smell. See Argentine ant.
• White-footed ant: pale feet, no strong odor.

Signs

• Trails of small dark ants in kitchens, especially around sinks
• A strong, sweet-rotten smell when ants are crushed
• Ants in bathrooms and around dishwashers
• Ants tending aphids on landscape plants

Prevention Tips

• Wipe sugary spills and keep sweets sealed.
• Fix leaks under sinks.
• Trim plants away from the house.
• Have a licensed lawn and ornamental provider address aphids and scale on landscape plants.
• Seal gaps around pipes and windows.

Odorous House Ants After Rain

The most common time for odorous house ants to invade is right after heavy rain. Their nests are shallow, often just under mulch, stones or a thin layer of soil, so a summer downpour can flood them in minutes. The whole colony, including queens and brood, then moves somewhere drier, and a kitchen wall void or the space under a dishwasher is a perfect choice. Homeowners often notice a sudden trail in the kitchen the morning after a storm.

If that happens, resist the urge to spray. Wipe the trail with soapy water if it's on a food surface, but leave some ants to find bait. Note where they're entering, such as a gap behind the sink, a window frame or a baseboard, so we can place baits and treat the exterior at that spot.

Identifying Ants Without Crushing Them

If you'd rather not test the smell, collect a few on clear tape and keep them for your inspection. Our technicians can tell odorous house ants apart from ghost, Argentine and white-footed ants, which helps us pick the right baits.