Camponotus pennsylvanicus

Carpenter ant adult. Photo: Clemson University, Bugwood.
Scientific Name: 
Camponotus pennsylvanicus
Common Name: 
Carpenter Ants
Growing Degree Days (GDD's): 
None available at this time.
Host Plant(s) Common Name (Scientific Name): 
Balsam Fir (Abies balsamea)
Cherry (Prunus spp.)
Northern White Cedar (Thuja occidentalis)
Sugar Maple (Acer saccharum)
Sweetgum (Liquidambar spp.)
Insect Description: 

Ants belonging to this genus are called carpenter ants as they seek out soft wood to make a nesting place for their brood or young. Camponotus pennsylvanicus may also be known as the black carpenter ant. Ant nests may be a few feet from ground level in the tree, including in living trees of the species mentioned here. These ants do not eat wood, but rather continually cut chips out of the wood in order to extend nesting areas. Wood chips may be carried away from the nest and dropped at the base of the tree. These wood fragments can be sawdust-like. Carpenter ants eat dead and live insects, honeydew, ripe fruit, and sap from certain plants, but do not eat wood. Standing dead trees and stumps can also be great places for carpenter ants to build nesting space for their young.

Damage to Host: 

Nests may be found in the interior of living trees, including sugar maple, sweetgum, Prunus species, northern white cedar, and balsam fir. They may be also found in standing dead trees, stumps, or wooden structures that are in a state of decay. While these insects do not feed on trees, the activity of them creating galleries and nesting locations for their brood can sometimes weaken the core of the tree and potentially make it hazardous. 

Monitoring: 

Look for sawdust-like wood chips or shavings at the base of a tree or near areas of decay. If shavings are long, like tiny match-sticks, and accumulating in branch crotches higher in trees such as maples, see Asian longhorned beetle and confirm that other signs of that insect are not also present.

Cultural Management: 

Trees that are home to carpenter ants should be inspected by a qualified arborist to ensure that they are not at risk of becoming hazardous. 

Natural Enemies & Biological Control: 

None noted at this time.

Chemical Management: 

No chemical management is recommended in trees harboring carpenter ant colonies. There are no chemicals recommended for ants in live trees. Ants are a sign that the tree has a more serious problem, such as decay. The infested tree may be or become hazardous and require removal. Carpenter ants can accelerate the weakening of a decayed tree.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: https://www.mass.gov/pesticide-product-registration .