Ants in the House
There are many types of ants that may be found in houses. Some are actual household pests, while others occasionally wander in to look for food or water.
Some ants which may be found in houses in the Northeast include: carpenter ants, little black ant (Monomorium minunum), pavement ant, (Tetramorium caaespitum), odorous house ant (Tapinoma sessile), Cornfield ants (Lasius spp.) Yellow ants (Acanthomyops spp.), acrobat ants (Crematogaster spp.), thief ants (Solenopsis spp.) and the pharaoh ant (Monomorium pharaonis). Carpenter ants may cause costly structural damage by their excavation of nesting galleries in wood. (See additional information on carpenter ants if this is the type of any you have).
Ants have three body regions (head, trunk and gaster) distinctly defined by narrow constrictions (Fig. 1). They have elbowed antennae, and the gaster is attached to the thorax by a waist that consists of one or two small separated segments.
There are three distinct castes of ants-queen, male and worker. There may also be different forms of each caste. Ants always live in societies known as colonies. Workers are wingless, but at mating time swarms of males and females are produced, usually winged.
- Store food in tight containers. Ants are often searching for sweets or greasy substances (chips) as food sources and are often found in kitchens as a result. Clean up pet dishes when pets are finished eating. Ants may feed on a number of foods including meats, dairy products, pastries, fruits, animal fats and vegetable oils as well as dead insects. If ants are a particular problem, it may be helpful to store especially susceptible foods in the refrigerator.
- Consider using ant traps or baits. Determine what the ants are feeding on - is it sweet substances, or protein or grease? Knowing what the ants are feeding on can help you to use ant traps effectively as a way of managing pest ants. Ant traps, which contain baits of boric acid or other poisons, attract the pest to the poison, avoiding the need to apply poison throughout the environment. In addition to traps there are baits available for ant pest management. The baits may offer a choice of sweets or protein and are more effective for a wide range of ants. (If ants are feeding on sweets, a bait with a sweet matrix may work best; on protein or grease - a protein matrix works best. However, some ants will switch food preferences, and if you are not sure which the ants like, there are products which offer both types of bait). Keep traps and baits out of the reach of children and pets. Although ant traps and baits are helpful for some species, they do not work for all species of ants. They also work when worker ants come and get food, not for swarming adults.
- Try to locate the ant’s nest and see if the ants can be excluded by needed repairs (caulking, repairing cracks in concrete floor, eliminating sources of moisture, etc.). Note the surfaces they crawl over and where the ants come from and where they go after feeding. This will help you determine if the ants are nesting inside, or coming in from out of doors. It is not always possible to locate the nest site - inside ants often nest between floor and sub-floor, in walls, behind baseboards, beneath cracked basement floors, in decaying or rotting wood, or even in piles of papers. If ants are nesting inside walls, opening walls to reveal nest, and quickly vacuuming up the ants can help to reduce or eliminate a colony. This often works best when the ants are inactive such as in the wintertime. Discard contents of vacuum bag after vacuuming up any live insects- insects may be killed by freezing if necessary.
- If problems persist despite efforts to correct situations which allow ants to enter and cleaning up food, it may be useful to spot treatment with a household insecticide labeled for ant control where ants enter. Pesticides should be used only as a last resort for ant control. Never use pesticides on food preparation or handling surfaces. Registered pesticides include Baygon, bendiocarb, cyfluthrin, deltamethrin, permethrin, silica gel - pyrethrum combination or resmethrin. Follow manufacturer’s directions for rates and application methods. Other products may also be registered.
- Some ants which nest in colonies in walls of houses and buildings will actually become more of a problem if pesticides are sprayed. This may cause the ants to scatter, and smaller colonies to become established. This life style of budding off of smaller colonies is frequently seen in the pharaoh ant.
Reprinted from Ants In Houses. Prepared by Carolyn Klass, Sr. Extension Associate, Department of Entomology, Cornell University4/1985. 11/2001, Revised by Carolyn Klass
This publication contains pesticide recommendations. Changes in pesticide regulations occur constantly and human errors are still possible. Some materials mentioned may no longer be available, and some uses may no longer be legal.
Recommendations and pesticide use may vary depending on on which state you live in.
Read the label before applying any pesticide.