Ants, common throughout Colorado, are easily distinguished from other insects by their narrow, pinched waists and elbowed or bent antennas. Most ants control insects and weeds and improve soils by building nests. Ants can be a problem when they forage for food during the warmer months. Carpenter and large black or red ants can damage buildings, and Pharaoh ants can move diseased organisms around, but most species of ants are just a nuisance. Field ants often nest near foundations and as spring arrives, workers search for food. The warmth inside the home draws ants and they search for sweets and morsels. As spring progresses, there are alternate foods outside so invasions are temporary. Another common ant is the pavement ant. This ant makes small soil mounds in sidewalks and driveway cracks. The pavement ant is probably the most common ant in Colorado. It is not a native ant but has successfully colonized here.
Remove crumbs, grease, food and scraps to make baiting more effective. Since ants nest outdoors, residual insecticides including Bifenthrin, Carbaryl (Sevin), Esfenvalerate, or Permethrin sprayed around foundations will keep ants from coming indoors. Ants track insecticidal dusts into their colony. Destroying ant nests is a more permanent control.
Ant baits or traps are sold commercially or bait can be made with a small amount of boric acid with something sweet or greasy. Some ants are attracted to sweet things, so mix boric acid with food like jelly. For ants attracted to grease, mix boric acid with foods such as peanut butter or pie dough. Use one tablespoon of boric acid to 10-20 tablespoons of food. Place the bait, covered with straw, along pathways where ants have been traveling. Placing the bait in straw helps keep children and pets away from the bait, which could poison them. The notion that ants can be totally eliminated from a home area and surrounding landscape is not realistic.
For more information, see the following Colorado State University Extension fact sheet(s).