The weather has finally become predictable: soggy wet with the chance of rain. As a result, basements are flooding, outdoor activities have been canceled, and many creatures are looking for drier places to live. Ants are at the top of this list. Recent record rainfall has forced these pests out of the ground and into our homes. So, if you turned on the kitchen light last night and found hundreds of ants covering the countertop, or moved a box in the garage and found thousands scurrying for cover, then here are some control strategies to help get the "ants out of your pants."
We typically think of ants as outdoor pests that invade the picnic table when we leave to play a game of volleyball. However, recent rains have flooded many of their nests, and the survivors are in search of drier ground. Whether they are temporary invaders or permanent tenants, control begins with finding the nest, a task much easier said than done. Ants typically follow regular routes or chemical trails between the food source and their nest. Watch the ants to locate their trail. Try to follow them back to the nest. Earlier this spring, I followed a trail from the kitchen counter to a nest located 30 feet away on the other side of a two-car garage.
If you are unable to locate the nest, consider treating the exterior of the house using an insecticide labeled for use as a lawn treatment. Apply the treatment in a 2- to 4-foot-wide area around the entire building. This treatment is temporary, and re-treatment may be necessary. Some examples of exterior-use chemicals are carbaryl (Sevin), Acephate (Orthene), and other various synthetic pyrethroids such as cypermethrin, cyfluthrin, lambda-cyhalothrin, bifenthrin and permethrin. If you find the nest, these same insecticides will work well as a directed spray to that area. Use caution when spraying, and read and follow all label directions.
If the population seems to only be visiting the inside of your home looking for a meal or a place to dry off, try using baits. Foraging workers feed on the bait and take it back to the nest where they share it with the rest of the colony. However, baits are slow-acting, and it may take several weeks to see a reduction in numbers.
Likewise, not all ants are equally attracted to baits. Ant baits that you buy in stores will be attractive to some species but not others. Experiment with foods that are attractive to the ants. Try peanut butter, sweets, fruit or meat products. A homemade bait can be made by mixing two parts boric acid to 98 parts of food attractant (1/4 teaspoon of boric acid to about 4 tablespoons of food attractant). These baits should be placed on small jar lids, pieces of cardboard, in straws or something similar. Locate the feeding stations in places where ants are commonly observed.
Finally, consider steps to prevent entry. It is generally assumed that careless cleaning habits in the kitchen will make the area more attractive to ants. Of course, it is hard to be specific about how clean is clean enough. However, when faced with an ant problem, increased efforts of proper food storage, waste disposal and cleaning of kitchen surfaces will be needed. In some cases, entry points can be sealed or caulked to prevent entry. Unfortunately, most ant species are tiny, making them more difficult to exclude than larger pest species.