Pavement ants tend to invade homes in the winter in search of food and water, though they can enter at any time of year (see References 1). Environmentally friendly methods of removing them can take more time than commercial pesticides, but a well-rounded approach will eradicate and prevent infestations.
Eliminate Food Sources
When eliminating ants from the home, it's important that you make your home undesirable to them. Pavement ants prefer greasy foods, sweets and proteins, so your primary preventive measures begin in the kitchen. Immediately after preparing foods, refrigerate any leftovers and clean the counter tops and appliances. Packaged foods that are not refrigerated after opening should be sealed in airtight containers. Vacuum daily to eliminate any tasty crumbs from the floor. (See References 2.)
If a group of ants travels in a straight line from your kitchen door to the cabinet, they are following --- and strengthening --- a scent trail of pheromones. Ants broadcast the location of food to other ants with these trails, so your eradication efforts should also focus on any areas they travel frequently. A mixture of vinegar and water dissolves the trail; however, the disruption is only temporary (see References 2). While implementing other control measures, repeat the application whenever ants appear in the treated area. Ellen Sandbeck, author of "Organic Housekeeping," recommends sprinkling paprika, peppermint leaves or red pepper on the trail to deter ants (see References 3).
Homemade ant bait helps you destroy the ants' nest without the use of chemical-laden pesticides. If you mix borax or boric acid in a greasy food, the pavement ants will carry morsels of it back to the colony and poison other ants. Ellen Sandbeck recommends one teaspoon of boric acid in 1/4 cup of bacon grease (see References 3). Too much boric acid in the bait kills the ant before the mixture reaches the colony, so the most effective mixtures contain small amounts of it.
Although borax and boric acid are relatively mild, pets and children could become sick from ingesting it. For this reason, bait should be kept out of reach or in a sealed glass jar with small holes in the lid. Bait-filled soda bottle caps are sufficient for out-of-reach areas. This is only effective if the ants find it, however. The University of Nebraska-Lincoln urges homeowners to locate infested areas by sticking lines of jelly-coated masking tape around the home. If you see more than 10 ants feeding on a line of jelly, it's a good place to set the bait. (See References 4.)
Perimeter control measures stop ants from entering the home. Rather than spraying pesticides outside, surround the foundation with a mixture of one part flour to two parts borax, as recommended by the Children's Hospital of Philadelphia (see References 5). Pavement ants tend to nest beneath concrete and enter the home through cracks, so it's also helpful to fill cracks around the home and foundation with caulk, borax or fresh concrete. (See References 1 and 3.)
- Michigan State University Extension: Pavement Ants (Tetremorium caespitum)
- University of Minnesota Extension; "What To Do About Household Ants"; Jeffrey Hahn, et al; 2003
- "Organic Housekeeping"; Ellen Sandbeck; 2006
- University of Nebraska-Lincoln; "Ant Baits: A Least Toxic Control"; Barb Ogg, PhD; 2011
- The Children's Hospital of Philadelphia: Safer Alternatives
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