Carpenter ants are among the largest ants found in Minnesota. Workers are usually black, or red and black in color and they range in size from 3/8 to ¼ inch in length. Winged ants may be up to 1 inch long. Size is not a reliable method for identifying carpenter ants. They nest in moist wood that includes rotting centers of tree trunks, tree stumps, tree roots, logs or boards lying on or buried in the ground, and moist or decayed wood in all parts of buildings.
They may also nest in foam insulation, roofing, and various hollow spaces in doors and wall voids. Carpenter ants do not eat wood for food, but they can excavate moist or dry sound wood for their nests. They feed on insects, meats, various sweets, grease, and honeydew from aphids and scale insects. There are other ants mistakenly identified as carpenter ants. A newly revised Extension Service publication ? Carpenter Ants, FO-01015-B, 2001 ? provides information that includes identification, what they eat, where they live, damage, spring and winter activities, prevention, detection and control (indoors, baits, outdoors, and in trees). This publication is available from your county Extension Service office. If you have access to a computer you can go to the web site www.extension.umn.edu and search their product catalog for item #01015, Carpenter Ants.