Carpenter Ants

Problem type: Insect

Name of problem: Carpenter Ants

Plant name(s): Stumps, fallen logs, standing trees, decaying wood

Symptoms / Characteristics:
Sighting of numerous working ants in an area can be the first noticeable sign of a carpenter ant infestation. Seeing ants does not mean that a colony is established in that structure as ant workers travel far distances in search for food. Mounds of shavings or sawdust can be found beneath cracks or slits in walls, crawl spaces or other wood members. Rustling sounds can sometimes be heard where the ants have nested. Carpenter ants like to nest in wall cavities, window panels, ceilings, between floors, under siding, small voids and where wood is in contact with soil.

Carpenter ants do not eat wood but excavate tunnels in wood to form their nests. They eat dead and live insects, fungus, honey dew secreted from other insects and other sweets, meats and fats. Carpenter ants are typically black but some may be reddish black. They are large ants measuring up to half an inch long. Colonies consist of one reproductive female (queen), males, workers, eggs, larvae and pupae. In the spring, winged ants swarm and mate and the female then sheds her wings and searches for a suitable site to begin their nest. This will be the main colony and as the colony matures, as many as ten satellite colonies can be formed and are linked to the main colony by trails. Ants are most active during the night but can be found throughout the day.

Control / Preventions:
Keeping wood from coming in contact with soil and maintaining dry conditions are important factors to reduce the chance of infestations. Proper construction and up keep of structures will prevent rotting wood for carpenter ants to thrive in. Remove any tree limbs that are in contact with the house. Seal cracks along foundation, siding, windows and doors with caulk and fix any leaks, as ants need water as well as food. Move firewood away from the house and keep elevated so it is not in direct contact with the soil. Remove any rotting or decaying wood nearby such as old stumps, logs, woodpiles, fences or other landscaping wood. By following ants along their trails, they may lead you back to their nest. Remove the nest manually or by vacuuming if the nest is found.

Diatomaceous earth is a dust that is available to control carpenter ants. A fine layer of dust can be applied to ant trails. The ants must come in contact with the dust for it to be effective. The dust cuts the bodies of the ants causing them to dehydrate. Dust use may not work in damp conditions as it will clump and not be picked up by the ant.

Chemicals insecticides and baits are also available for carpenter ant control. Read and follow all labels on control products for safe, effective control.