Thief ant workers are usually less than 1/16″ long. They are so small that many people do not notice them in the kitchen. The thief ant workers are so small that they can squeeze into food packages that appear to be sealed.
Thief ant workers make their nest outdoors in the soil. They often nest under logs, stones, or landscape timbers. They forage inside homes to find food or water. When they have found a food supply, they frequently make a nest indoors.
When they make an indoor nest, thief ants often move into a wall void or the base of a cabinet. Because they are so small, the ants can nest in crevices such as the crack behind woodwork like baseboards.
Thief ant workers seem to wander around when they are searching for food. After they have found a food supply, they move in a line between the food and their nest.
Control of thief ants is easiest if the nest can be located. Following the line of workers will often lead to the nest. If the nest is located, aerosol, dust, or liquid insecticide can be used to treat it directly. Be sure to follow the label directions for mixing and applying insecticide.
If the nest cannot be located, bait may be the most effective way to control thief ants. The workers seem to prefer liquid or gel bait, but solid bait will also work. Place the bait near the ant trails, but be sure children and pets cannot reach it.
If the ants accept the bait, they will go to it in large numbers. When the ants are feeding on bait, people sometimes think the ant problem has gotten worse. If the ants do not accept the bait, it may be necessary to try another type. Ants can be picky about food, and it can test your patience.
Do not disturb the bait, but keep the stations filled with fresh bait as long as the ants are feeding. It is important that all of the ants get to eat some of the bait. If some of the ants survive, they will re-infest and the problem will soon be as bad as before.
An insecticide barrier on the outside foundation can help prevent thief ants from invading the home. Because of the effects of sunshine and rain, the barrier will have to be re-applied periodically.
Because of the equipment and insecticides that are needed, many homeowners find it is simpler to have a pest control professional do everything that is necessary to take care of these pests.