The best way to control carpenter ants is to locate and destroy the nest, replace damaged or decayed wood and eliminate moisture problems, if they exist.
Eliminating a carpenter ant nest can be difficult because of the hidden nature of the nest. Carpenter ant control is usually best done by an experienced pest management professional. They have the experience, equipment and a wider array of products to more effectively control a carpenter ant problem.
You can help by telling the pest management professional about when, where and how many ants you’ve seen.
There can be more than one nest in a building, but only treat nests that have been discovered.
Indoor treatment with dust or liquid pesticides
Spraying foraging workers is not effective. It may temporarily reduce the number of ants you see. However, this will not eliminate a nest because:
- Ants carry very little insecticide back to their nests.
- Most ants forage outside and do not come in contact with the insecticides.
- Only a relatively small percentage of a colony’s population is out foraging at any given time.
Nests are often hidden in wall voids, ceilings, subfloors, attics or hollow doors. It is sometimes necessary for a professional pest management applicator to drill small (about 1/8 inch) holes and apply an insecticidal dust into the nest area. This is neither practical nor recommended for you to do this yourself.
Determine the nest’s location as specifically as possible. Control should not be applied randomly through the home.
If the nest is exposed (for instance due to remodeling or reroofing), you can use a liquid or aerosol ready-to-use insecticide.
- Common products include cyfluthrin, cypermethrin, deltamethrin or permethrin.
- The more of the colony that is exposed, the better your chance of destroying it.
- Be prepared to find a carpenter ant colony and have a product ready at the start of construction.
- Once the nest is exposed, that portion of the colony will try to relocate to protect them.