Killing Carpenter Ants in Your Tree and What They Mean

Killing Carpenter Ants in Your Tree and What They Mean

Black carpenter ant represents decay when nesting in trees

Do you see big black ants crawling all over your tree? While carpenter ants need to be controlled, they are the least of your worries and indicators of potentially bigger problems.

Carpenter ants nesting in a tree are a sign of a more pressing problem that, if not addressed, will kill your tree, leaving the ants to move on to a new home. gathered information on how to eliminate carpenter ants from your tree and what an infestation means.

How to Get Rid of Carpenter Ants in a Tree

When carpenter ants invade a tree, there is a risk that they will also invade nearby structures. Within a typical carpenter ant colony, foragers continuously seek new sources of nutrition or a suitably sheltered location to either move the colony to or form satellite colonies.

The best time for controlling carpenter ants is when activity is at its height during the spring and summer months. During the winter, they will hibernate unless located near a constant source of heat.

When attempting to eliminate a carpenter ant infestation, you are searching for the following:

Parent Colony – The parent colony contains an egg-laying queen, workers, and numerous broods. These colonies can be found in:

• Rotting tree stumps
• Injured or dying trees
• Within the walls or wooden features of a structure frequently exposed to moisture

Carpenter ant colony nesting in decaying tree

As ants are capable of foraging and traveling great distances from a parent colony, your search for either a parent or satellite colony should be as broad as possible.

Satellite Colonies – A satellite colony may contain pupae, mature larvae, and workers.

Common places to find satellite colonies are:

• Within the rotted wood of old window frames.
• Shingles or wood siding exposed to constant moisture.
• Nearby trees with declining health or previous stressors.

Controlling an infestation of ants inside a tree is a difficult task which must be done to prevent the creation of satellite colonies and the invasion of surrounding structures.

Dust insecticides that contain pyrethroids or carbaryl designated for use on landscape trees are suggested for control:

• Apply the dust directly into and around the nest cavity.
• Watch for foraging ants and dust along the path they travel.
• Annual retreatment may be necessary, as carpenter ants are difficult to control in trees.

Liquid insecticides that contain a sugar based bait and borax as the killing agent are among the most effective long-term solutions available. For DIY or homemade insecticidal soap recipes, see then below outlines how to apply the solution:

Liquid insecticide for carpenter ant control in a diseased tree

• Spray the insecticide in and around the nest cavity.
• Follow the ants along their trail to find other holes, or entryways to satellite colonies and spray them.
• This is a slow acting insecticide which allows the ants to carry the poison back to the nest and feed it to others.

In either case, never disturb the nest before applying the dust or liquid insecticides. When ants get “spooked” or sense danger, they erratically and quickly leave their nest, will avoid consuming the poison, and may prompt some to stray off and begin another colony.

This picture shows a nest cavity before applying an insecticide.

Diseased and decaying tree with carpenter ant colony infestation

This picture shows the same nest cavity immediately after applying an insecticide.

Carpenter ant colony leaving insecticide treated tree

NOTE: Ants leave a pheromone trail behind them for others to follow and for them to return to their colony. By dusting or spraying along their path, you are increasing your chances for successful control.

What a Carpenter Ant Infestation Means

Carpenter ants are opportunistic in nature. They differ from termites in that they do not eat wood or pulp, rather they burrow through it. To accomplish this in trees, they take advantage of a preexisting condition that has weakened, killed, or caused decay within the tree.

Environmental issues, previous infestations, poor pruning habits, and disease can all contribute to the declining health of a tree, and the successful infestation of it by carpenter ants. Knots, old insect tunnels, holes, cracks, and poorly healed pruning cuts can all offer access to carpenter ants. For more info on common tree diseases, see

As a growing carpenter ant colony burrows into the heartwood of a tree, you are likely to notice the partial or complete dieback of branches and limbs.

Carpenter ant infested tree with branch dieback

Once a carpenter ant infestation is confirmed, have your tree inspected for signs of disease, other insect infestations, fungal infection, and rot. Again, carpenter ants are the least of your concerns. If they are present and thriving, it is due to other issues that have debilitated your tree’s defenses.

Avoid dressing or sealing wounds and cavities. This will not eliminate or prevent carpenter ant activity or the decay that made their presence possible.

The removal of your tree, based on an ant infestation, should only occur if absolutely required for the safety of your property.

Carpenter Ants and Tree Health

Black ants crawling all over your tree are signs of decay within the tree and represent an urgent need to identify the preexisting condition that gave them access in the first place.

Carpenter ants on a diseased tree

In this article, you discovered methods to control and eliminate carpenter ants from your tree, and what their presence means for its health.

Your delay in controlling a carpenter ant infestation allows the colony to burrow deeper into your tree while establishing satellite colonies in other trees and structures around the parent colony. The longer you wait, the larger, more invasive, and more damaging this species of ants will become.


Todd’s Marietta Tree Services

200 Cobb Pkwy N Ste 428 Marietta, GA 30062
(678) 505-0266

The post Killing Carpenter Ants in Your Tree and What They Mean appeared first on

Leave a Reply

Your email address will not be published.

This website nor its owners are an actual service provider, this website is a referral service. When you place a phone call from this website, it will route you to a licensed, professional service provider that serves your area. For more information refer to our terms of service.


(877) 959-3534