Carpenter ants are a familiar sight throughout the United States. Among the largest of ants, carpenter ants are ¼” to ½” long, black or red and black and may or may not be winged. Dormant in winter, swarms begin to appear in the spring and early summer. Colonies number in the thousands and when an infestation has set in, they are hard to miss. They feed on aphids, scales and other plant-damaging insects and the honeydew (a sweet, sugary excrement) they produce. Carpenter ants clean up pest debris in the garden and promote composting of rotting wood. A beneficial insect. What’s not to love? If you’ve had to deal with an invasive carpenter ant population, even that question may have you gritting your teeth.
Although they do not eat wood as termites do, they seek out and destroy damp or rotting wood in which to make their nests. And they are very good at it. In the forest, nests chewed into tree stumps or fallen timber aren't a problem. For homeowners, however, the aggressive damage done by large populations of carpenter ants can wreak havoc on houses, fences, outbuildings and decks. Once they’ve entered the home, they can be found in attics, crawlspaces, window and door frames, subfloors and around sinks or tubs.
Nesting damage done by these so-called beneficial bugs is swift and overwhelming. A healthy colony may consist of thousands or hundreds of thousands. With sheer numbers in their favor, property damage can become extreme before control methods are even considered. While carpenter ants do not sting, their bite is painful and can be hard to avoid in a heavily infested yard. Even with the benefits they can bring to a burgeoning crop by controlling those plant-eating pests, the problems they bring far outweigh any potential benefits.
Managing a carpenter ant infestation can be difficult, but steps can be taken to reduce the damage done by these destructive visitors.
Limit nesting opportunities. Clear out fallen branches from the yard, remove rotting tree stumps and prune dead branches from trees. Water-damaged wood on structures should be repaired and store firewood or lumber away from structures.
Avoid standing water. Level ground along fences or structures where water may pool and repair any leaky gutters or downspouts. Install moisture barriers under porches and other water-prone locations.
Remove food supplies. Control of honeydew producing pests in the garden may discourage a developing carpenter ant colony. Carpenter ants covet aphids and will tend to them much like a farmer tends to livestock, even carrying them between plants to promote their favorite food source.
Destroy nests. If a carpenter nest is discovered, it is possible to remove it by removing the infested wood, but extended nesting locations are often overlooked and may warrant professional assistance.
Chemical treatment. If a nest cannot be detected, use of chemicals may be necessary. Spray insecticides are usually ineffective against a large nesting colony. Baiting can control a carpenter ant population, but requires diligence. Bait must be placed where ants have been spotted and replaced regularly until problems subside. Again, hiring a professional pest control service to manage a chemical solution may be the most reliable course of action to put an end to a carpenter ant infestation before further damage to property is incurred.