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How do I control my ant problem?

ant graphic

It’s happened to all of us. You stroll into the kitchen and find ants marching all over your counter. It seems they’re taking over the whole house.  Although it may be tempting to think the world would be a better place without these pesky critters, it’s important to keep in mind that ants play an important part in maintaining healthy ecosystems.

Ants help control numerous insect populations. They have been called “the foremost predators” and are superb scavengers. Because many ants build their nests in soil, they play an important part in keeping outdoor soils healthy. Ants, along with termites, “turn more of the soil  than earthworms.”

Despite the beneficial role ants play outdoors, ants become pests when they enter homes in search of food, water, and shelter. If ants do invade your house, don’t panic. A management plan based on cleanliness and physical controls can help reduce household ant populations.

Proper identification of ants is the first step in managing nuisance ant problems.3 People often confuse ants and termites, especially during swarming when winged forms of ants are often mistaken for winged termites. By examining the waist and antennae, you can easily tell them apart. Ants have narrow waists and “elbowed” or bent antennae. Termites have broad abdomens with no waist and straight, beaded antennae. Ants have hind wings smaller than front wings. Termites have front and hind wings that are about the same size. If the insect is a termite see “Dampwood Termite Solutions” JPR 21(4):12-13, “Drywood Termites” JPR 17(4): 22-23, and “Subterranean Termites” JPR 17(1): 22-23 and 17(2): 21-22.

Your next step is to determine whether or not the insect is a carpenter ant. If you have carpenter ants, you will see workers varying in size from 1/4 to 1/2 inch. Nuisance ants are usually smaller—1/8 to 1/4 inch. Also, carpenter ants will often leave piles of sawdust at nest openings and make rustling noises in the walls, ceilings, or floors. If the insect is a carpenter ant, read “Living with Carpenter Ants

Only a few ant species become household problems in the Northwest. The most common house-invading ants are listed in the table on the next page, along with some identifying characteristics. Your local Cooperative Extension office can help you identify your species of ant.

As with any pest problem, the easiest and most environmentally-sound solution starts with prevention.

Control Measures
Ants are unlikely to become pests in large numbers if sanitation and physical controls are followed carefully. Completely getting rid of ants may not be possible. Tolerating a few ants in your home may be a more realistic goal.

Toxic pesticide sprays and dusts are poor choices in managing ant populations. Using pesticides can make your ant problems worse by  causing colonies that reproduce by budding to split up into multiple colonies.  Most pesticide applications are not directed at the nest, and because in some species only 5 percent of a colony’s workers are out foraging at any one time, they can leave 95 percent of the colony intact.

Ants are attracted to a variety of different foods. Thorough daily cleaning is essential for  successful ant control.  Here are some useful tips:

  • Keep kitchens and other rooms as free of food as possible. Wipe all kitchen surfaces with soap and water to keep free of grease and spills.
  • Food not kept in the refrigerator or freezer should be in tightly sealed containers. Ants can crawl up the threads of screw-top jars, so use glass jars with rubber seals and metal clamps or plastic containers with tight-fitting, snap-on lids. Rinse all food and beverage containers thoroughly before disposal.
  • Place food scraps and leftovers in tightly sealed containers, such as storage containers with snap-on lids or plastic bags, for composting or outside waste disposal. Empty garbage daily, and clean waste containers frequently.
  • If you can’t wash your dishes after every meal, rinse to remove food residues and place in a sink full of soapy water. Sweep or vacuum floors thoroughly and frequently.
  • Pet food should be kept in tightly sealed containers. Keep your pet’s eating area clean. If you need to leave dry pet food out, place the food bowl in a slightly wider shallow pan of soapy water.
  • Containers of food that cannot be sealed can also be placed in these soapy “moats.”
  • Keep kitchen and bathroom areas dry. Wipe counters, eliminate standing water, and fix leaky faucets.
  • Ants sometimes nest in potted plants. If ants are found, take the plant outside and submerge for 20 minutes in standing water. Ants should crawl out, but repeated floodings may be necessary.
  • A temporary solution to gain quick control of ant invasions is to mix a teaspoon of liquid soap in a quart-size spray bottle filled with water, spray areas where ants are active, and wipe up the dead ants with a sponge. This will destroy the chemical trails left by worker ants.

Seal Entryways
To keep ants from entering your home, fill cracks and crevices that provide entry from outside with silicone caulk. Seal around baseboards, moldings, cupboards, pipes, ducts, sinks, toilets, and electrical outlets. A temporary seal can be made using petroleum jelly or duct tape. Weather-strip  around doors and windows.

Replace Rotten Wood

When moisture ant colonies (yellow ants and cornfield ants) are found in the home, it is an indication of moisture problems and decaying wood. The ants nest in wood in the last stages of decay, so their presence is an indication of a prior problem. Repair moisture problems and replace decaying wood.  ther control measures are usually not needed and only provide temporary
control unless underlying moisture problems are corrected.

Landscape Control
Some ant species are attracted to the sweet honeydew deposited on plants by aphids and scales. Reduce the numbers of these insects on trees and shrubs near your house. (Read “Managing Aphid Problems Without Pesticides”) Consider removing plants that host these insects.

Trim branches of trees and shrubs that touch your home to keep ants from crawling across to the roof or siding. Provide a dry, vegetation-free border, such as brick walkways or stones, around the house foundation to discourage nest building. Avoid stacking wood or trash next to structures. Regularly inspect compost and firewood piles, plant containers, and woody  debris for ants.

Control of Colonies
If cleaning up food sources and sealing off entryways is not controlling your ant problem, you will need to destroy the colony. To locate a nest, try following a trail of ants until they disappear. You can also place syrup or honey on cardboard or wax paper squares along ant trails. A thick trail leading from the syrup can help you pinpoint the nest. If the nest is found  outdoors, pour large amounts of boiling water directly into the nest to destroy it. Use a full pot of water. Repeat if necessary.

Indoor nests are often found in walls, under floors, in cracked windowsills, in electrical outlets, or even in piles of old newspapers. Ideal locations are anywhere there is heat and moisture. Check around hot water heaters and under sinks, bathtubs, and toilets. To eliminate an indoor nest, use a vacuum with a High Efficiency Particulate Air (HEPA) filter. Use a mask for  personal protection. Put a little cornstarch in the vacuum bag to help suffocate the ants. Always remove the vacuum bag, seal the opening, and dispose of promptly.

Do You Feel You Must Use Pesticides?
NCAP does not recommend the use of pesticides; however, we recognize that some people may feel they must use them. If you feel use of a pesticide is unavoidable, consider using a bait product. Commercial bait stations are available in enclosed containers. This type of application can reduce unwanted exposure. Because they contain poisons, NCAP believes that it is crucial to always place baits out of the reach of children, pets, and wildlife.

Ants can be difficult pests to manage, but with diligent monitoring and elimination of the conditions that contribute to infestations, you can be successful.

By following the tips in this article, you can effectively reduce ant populations indoors without using toxic chemicals or interfering in ants’ ecological roles outdoors.


Read MORE about ants (biology and helpful chart of types of ants)

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