Most indoor ants do not do much real damage except for carpenter ants (Camponotus spp.), which may burrow through structural wood in the home. Mostly, they are annoying and can sometimes spread unwanted bacteria. Read on to learn how to combat an ant problem and prevent it from recurring.
Structure of an Ant Colony
Ants are social creatures that generally form colonies in which individuals assume different roles. One or more "queen" ants are the reproducing individuals that remain in a hidden nest; their role is to simply continue to produce more ants and maintain the colony. The other individuals—which can include several million individuals in larger colonies—are known as worker ants. The younger workers typically remain inside the nest, where they serve the needs of the queen and maintain or expand the nest, while older workers roam out from the nest to retrieve food for the colony. It is these older workers that you see when an ant infestation becomes apparent.
An ant infestation is never controlled if all you do is spray the ants that are visible because these are just the older, worker ants that are following established trails to and from a hidden nest somewhere in the walls of your home. Although it sounds strange, the key to eliminating visible ants is to target those you don't see. This is because the queen—the one that lays all the eggs—never leaves the nest. She just stays hidden in the nest, being fed by the worker ants. So if all you do is spray the visible worker ants with pesticides, the queen simply produces more to take their place, and your infestation never ends.
The key, then, is to identify and target the queen ant, and this can be quite tricky since the nests are often deeply hidden behind walls or beneath concrete slabs.
3 Ways to Get Rid of Ants
The key first step in removing ants from the home is to identify the trails used by worker ants to move to and from the nest. Any visible ants moving inside your home are seeking food, and once they find edible material, the worker ant carries it back to the nest. By doing so, the ant leaves a chemical path, or trail, for its fellow worker ants to follow to collect more food.
This behavior is what makes it possible to combat ants, since you can now fool the worker ants into bringing some form of poisoned food (ant bait) back to the nest.
Use Ant Baits Indoors
Avoid the temptation to simply use pesticides to spray visible ants marching along trails inside your home. Pesticide sprays can eliminate a few visible ants, but more will quickly replace them, and you'll never make real progress to eliminating the infestation. Instead, use these worker ants as the ticket into the colony by placing ant killer for them to carry back to the hidden nest.
Ant baits are edible materials, usually sweet, sugary carbohydrates, mixed with substances that are toxic to ants but which have minimal toxicity to animals or humans. Some ant baits are primarily made from boric acid, a natural substance that is non-toxic to humans when used properly.
Ant baits can be "stations" containing granular materials or liquids that are sprayed onto surfaces. Whatever form of ant bait you use, try to place it close to visible ant trails but outside the reach of pets and children. The bait will work most effectively if you keep other surfaces clean so that the bait is the only sweet substance available to attract the ants.
The worker ants will carry the pesticide bait back to the nest, but it can take several days to eliminate the colony, or even a few weeks if the colony is very large or it has several queens, as some ant species do. You may even need to replace the bait station if the ants empty it. Gradually, though, you will see an end to the infestation.
Use Spray Pesticides Outdoors
If you happen to follow ant trails and identify an outdoor nest for the colony, then it may make sense to apply a heavy dose of liquid pesticide that can soak down to reach the queen. Drenching the nest with an approved insecticide spray (following all label directions) can be effective. Make sure, however, to verify that this is the colony creating your indoor infestation problem. Many types of ants are helpful garden creatures that you have no reason to kill.
If you use a general-purpose pesticide to kill ants, be aware that these chemicals can kill helpful insects, such as honeybees and predatory insects, as well as unwanted ants. It's best to use a selective pesticide that targets only ants, wherever possible.
Keep Things Clean
Sanitation is critical for the prevention and control of any pest. Like all living creatures, ants need water, food, and shelter for survival. Ants leave the shelter of their colony to find food and water. Don't make it easy for them. Keep foods sealed, floors swept, and all surfaces cleaned. Be especially careful to keep things clean while you are targeting the nest, as this will make the sweet ant bait the only thing available to the ants. But don't clean away the ant trails until you have eliminated the infestation, as these trails will allow the ants to find your bait and carry it back to the nest. Once you get rid of the ants, clean up the trail surfaces and keep them clean.
How to Cheaply and Naturally Get Rid of Ants
What Causes Ants in the Home?
Ants are common pests inside homes for very simple reasons: Indoor spaces, especially kitchens and pantries, offer sources of food and shelter for them. Crumbs, spilled foods, and pet foods are very attractive to ants, and the dark spaces in walls and below floors offer them plenty of areas to create nests. Eliminating and preventing ants is largely a matter of denying them food substances and nesting areas.
How to Prevent Ants in the Home
Ants are tiny creatures and can enter homes and buildings through minute cracks and crevices. To minimize this, seal around windows and doors and all cable, pipe, and wire entry points. Regularly inspect foundations for tiny cracks through which ants can gain entry to your home.
And keeping things clean of crumbs and storing foods in sealed containers will deny ants the foods they seek and eliminate the principal reason they come indoors in the first place.
Ants vs. Carpenter Ants vs. Termites
There are several types of common ants found around the home, and it's important to identify what you're dealing with in order to take proper measures.
The species you most commonly see inside the home are pavement ants, odorous house ants, and pharaoh ants (also known as sugar ants). These species are found in most U.S. states, and they feed heavily on sugars, greases, and other substances commonly found in residential kitchens. They can be dark brown, black, or light yellowish-brown in color, and while very annoying and potentially unsanitary, they do not pose much serious risk.
Carpenter ants (Camponotus spp.), however, are another story. These relatively large ants (up to 5/8 inch) are reddish-orange to black in color. If you see ants with wings, it's likely you are dealing with worker carpenter ants. Carpenter ants are more serious pests than most species, as they feed mainly on decaying wood, and the tunnels they cut in a home's wood framing in order to get at the decaying wood can wreak substantial structural damage. A clear sign is if you may also see residual wood dust and debris around the foundation and sill plate of the home, material removed by the ants as they bore tunnels in your home's framing.
Even more serious than ants are termites (Isoptera spp.). At first glance, termites and carpenter ants can look much the same in terms of color, size, and the type of damage they inflict. When you look closely, however, a termite's body will not have the narrow "waist" and clearly segmented body found on carpenter ants. Termites also have four wings of equal size, while carpenter ants have hind wings that are shorter than the forward wings.
If either of these pests is identified, you should consider bringing in an exterminator for consultation, as they can cause substantial structural damage if not controlled.
Do ants destroy wood?
Not all ants pose a risk to wood framing in your home. Only the carpenter ant poses this kind of risk to your home's structure. The other, more common ants, are more of a nuisance than serious danger.
When should I call a pro?
If you suspect carpenter ants are tunneling in your walls, you probably want to call a professional pest control service for consultation and treatment. Most other ant infestations can be dealt with by a homeowner, though it may take patient effort over several weeks or even months. But if an ant infestation persists even after diligent efforts to control them, then consult an exterminator for next steps. If you suspect termite damage, then professional attention is a must, as is having a professional replace any structural wood that has been damaged.
Are there natural treatments for controlling ants?
The most common substance in the ant baits used to disrupt the reproductive cycle of ant colonies is borax, a natural substance that is not toxic to humans or pets in small quantities. The most common ant sprays use pyrethroids or pyrethrin compounds, derived from chrysanthemum flowers, which work by paralyzing ants. They are low in toxicity to humans or pets.
But if you want to avoid synthetic chemicals of any kind, there are a variety of natural controls you can try for eliminating and discouraging ants. Most of these are more effective at repelling ants than killing existing colonies, but they are worth trying before you resort to purchased chemicals.
Some substances that often work to get rid of ants include:
- Herbs and spices
- Essential oils
- Coffee grounds
- Cucumber or citrus peels
Boric Acid for Ant Problems. Department of Agriculture and Natural Resources, University of California.
How to control invasive pests while protecting pollinators and other beneficial insects. Michigan State University.
Pyrethrins General Fact Sheet. National Pesticide Information Center, Oregon State University.