Grease Ants are Still a Problem

News Article

If we can invent a non-stick frying pan, why can't we invent an easy cure for grease ants!?!

Grease ants are among the smallest ants found in homes in Iowa. They are also one of our most persistent and difficult to control species. Grease ants are technically known as thief ants. They are very small and at only 1/16th inch in length, are easy to overlook except for the large numbers that appear simultaneously to form foraging trails from food sources to the nest. Grease ants are smooth and shiny and may be yellow to light or dark brown. Indoor nests are located in cracks and crevices of walls and cabinets, under floors and behind baseboards. Exact nest locations are rarely known. The ants travel great distances in search of food. Though they will eat almost anything, these ants prefer to eat grease, fats and meats.

Our best success at controlling grease ants has come by using insecticide bait. Several applications are usually necessary to eliminate a colony as re-appearance of the ants after a week to 10 days is common. Sprays of residual insecticide such as "ant and roach killer" applied into cracks and crevices in the vicinity of the nest may also be effective.

Most available ant baits, such as Terro , can be mixed with a grease or oil to make them more attractive to grease ants. Any grease or oil that can be mixed with the bait should be effective. I suggest vegetable oil or peanut butter. The bait-oil mixture must contain enough grease to be attractive, but not so much as to over-dilute the active ingredient. Though exact proportions of the most effective mixture are not known, I suggest starting with one drop of oil to 5 drops of bait. If ants are not attracted to this mixture, try another oil or increase the amount of grease in the mixture.

Small amounts of the bait and oil can be mixed together on wax paper and then transferred to the area of ant activity. The bait can be placed on small squares of paper, the non-sticky side of small masking tape strips or directly on the ant trail. Use baits with care. Make sure the bait is out of the reach of children and pets. When ant activity has ceased, carefully dispose of the remaining bait.

This article originally appeared in the July 27, 2001 issue, p. 97.