Q We're having a problem this winter with tiny ants. How do you get rid of ants in winter?
A The most common ant seen in winter is the pavement ant. The small, reddish-brown ants (about 1/8 inch long) nest in the soil, often under sidewalks and driveways. Nesting beneath a heated concrete foundation or cracks in the foundation blocks will keep them warm, active and in your house in winter.
Pavement ants prefer greasy foods and often feed on pet food. Baiting is the best control option. A common bait is Terro brand. If that doesn't work, try a commercial trap that attracts grease-loving ants. You might also try mixing a homemade bait using ¼ teaspoon boric acid with 4 tablespoons of peanut butter. Be patient; it can take weeks or even months to eliminate the colony through baiting.
Yellow ants also can be a nuisance in winter. You'll rarely see the worker ant, but will encounter what are called swarmers. Those yellowish-brown or darker ants are males and queens released by the colony to reproduce. Yellow ants give off a distinctive lemon or citronella smell when crushed. The colony is subterranean and is probably located under a concrete slab or next to a foundation wall.
Yellow ants are harmless and control is rarely warranted. Just vacuum up the swarmers; they are a temporary problem. If you must spray, apply an insecticide registered for indoor flying insects.
Some less common species can show up in the winter, such as pharaoh ants, thief ants and cornfield ants. Each species behaves in a different manner and requires control programs specifically tailored to it. Proper identification of the ant determines the best method for eliminating the nest. (The Extension Service can help with that. Go to the University of Minnesota Extension website, www.extension.umn.edu, and type "ants" in the search window.)
Information from University of Minnesota Extension