How to Get Rid of Carpenter Ants: 8 Treatments for Ants

Carpenter ants are a type of ant found in forested regions, making them native to many parts of the world. They have a dark head and thorax and are one of the largest ant species, growing up to three quarters of an inch long. Black carpenter ants are among the most common kinds, and they carve out space in dead or damp wood to build nests, called galleries.

Carpenter ants are similar to termites in the damage they cause, but unlike termites, they do not eat wood. They chew it out with their mandibles, discarding wood as small bits that look like sawdust shavings. Carpenter ants hollow out wood and leave gaping holes, maiming trees and causing damage to wooden structures in homes and buildings.

As both scavengers and predators, carpenter ants eat dead insects and consume honeydew, a fluid produced by aphids. Carpenter ants farm these aphids, protecting them so they can then consume their honeydew. These ants will also eat other sugary foods, such as honey, juices, or syrup, which can draw them to specific environments. Once there, they settle into moist or hollowed wood, creating their galleries to travel from one to the other freely.

Carpenter ants mate in humid weather, which is when ant problems usually spike. After mating, the males die, and the fertilized females head to the parent colony or one of the satellite nests. There they can lay up to 20 eggs and protect their larvae. These galleries may be in warmer woods or indoors, often behind baseboards or in wall voids. They might migrate near sources that trap moisture like faucets, windowsills, or door frames. In forests, carpenter ants play a crucial role in forest decomposition.

There are several telltale signs to help homeowners identify carpenter ants:

1. 1. Presence of ants: Black carpenter ants look similar to other ants, but their antennae are bent, not straight. They also have a cinched waist and two sets of wings. Just one on a countertop near food does not necessarily mean there’s a nest, but spotting a few might indicate carpenter ant colonies are nearby.
2. 2. Frass: The fine, sawdust-like material carpenter ants leave behind is known as frass. If you spot piles of powdery wood shavings on surfaces or caught in spider webs, carpenter ant nests may be near. Frass can also be a byproduct of termites.
3. 3. Sounds: The gnawing of carpenter ants’ mandibles can emit a faint but audible rustling noise.

The first step to getting rid of carpenter ants is to locate the woodpiles, parent colonies, and nearby satellite colonies. A combination of insecticide and baiting can combat a carpenter ant infestation:

1. 1. Bait: Place carpenter ant bait along the ants’ trail or near their nest to kill the ants. Worker ants will take the bait to the central and satellite nests. Using a combination of ant baits ensures the ants will go for at least one of them. Keep insecticides away from the bait; otherwise, the carpenter ants won’t take it.
2. 2. Non-repellent insecticides: These insecticides are harder for ants to detect, meaning they’re more likely to crawl through them. Ants will bring the non-repellent insecticide back to the parent colonies, killing the queen ants and slowing population growth. To use, create a perimeter treatment, spraying the non-repellent insecticide around the edges of your house. Spray three feet up onto walls and three feet away from the exterior to ensure a solid perimeter treatment.
3. 3. Dust: Spray insecticide dust into an infested area to poison and kill carpenter ants. Using insecticide dusters makes the job easier and allows you to spray into the crevices of baseboards, wall voids, or door frames. This method is simple and long-lasting, making it a popular choice for dealing with carpenter ant infestations within the home.
4. 4. Aerosol: If you suspect carpenter ant nests are inside a wall, aerosol can be an efficient way to take care of them. Drill a few eighth-inch holes into the space around the infested area and use an aerosol spray bottle with a crevice tip to target various areas and kill the entire colony.
5. 5. Boiling water: If you locate ant trails outdoors, boiling water can act as a quick fix. Boil a pot of water and pour it on top of the ant trail. The hot water will drown, scald, and kill the ants. You may need to repeat this a few times, but it is a simple option that won’t require a professional exterminator.
6. 6. Dish soap: Combine two parts water and one part liquid dish soap, mix it up, and pour it into a spray bottle. The soap is toxic to carpenter ants and will kill them. As a DIY solution, you can also spray it around entry points to help ward off ants from getting into your home.
7. 7. Baking soda: Create your own ant control by combining equal parts baking soda and powdered sugar. Place it around a nest—the sugar will attract the ants, and the baking soda will kill them. Repeat this method as needed to keep the carpenter ant population in check.
8. 8. Essential oils: Carpenter ants rely on pheromone trails to locate food. Using essential oils is an all-natural way to throw them off the scent and deter them from returning to the targeted site. Cedarwood, peppermint, and tea tree all work. Take a cotton ball, wet it with whichever essential oil you have, and swipe it along countertops, windowsills, and door frames to keep the ants away.

Grow your own garden with Ron Finley, the self-described "Gangster Gardener." Get the MasterClass Annual Membership and learn how to cultivate fresh herbs and vegetables, keep your house plants alive, and use compost to make your community—and the world—a better place.