In their natural surroundings, carpenter ants are beneficial insects. Excavation of galleries in wood has earned them their name. They are beneficial since they feed on many pests. They are the largest of our common ants, the brown or black workers measuring from 6 to 13 mm (1/4'' to 1/2") in length, while the queen may be more than 25 mm (1'') long. In late spring and early summer, mature carpenter ant colonies produce winged adults. These swarm in mating flights, and may be a nuisance around homes at these times.

Outdoors, they nest in any wood that is in close contact to a moisture source, for example, stumps, landscape ties and wooden fence posts. In buildings, they often make their nests in hollow doors, in wood cabinets near dishwashers, in damp locations behind baseboards, fireplaces, window frames, and in basements and attics. Carpenter ants will rarely do extensive damage to wood. They usually limit the size of the colony to the area of the damp wood. Several so-called satellite colonies may, however, be constructed in the same structure.

Carpenter ants may be seen in infested buildings at any time of the year searching for food at considerable distances from their nest. In some colonies, a dormancy period occurs for several weeks during the winter months. Although they chew their way through wood, leaving frass particles resembling sawdust, they do not eat wood. Instead, they feed on a wide range of insects, plant materials and, occasionally, on household foodstuffs.

Questions & Answers

How do I recognize a carpenter ant?

The carpenter ant is a large member of the ant family, measuring 6 to 13 mm (1/4" to 1/2"). Colour is either black or black with red. Antennae are elbowed and they have large heads with strong mandibles (jaws) used for chewing. Reproductive forms are winged.

Do carpenter ants cause damage?

Yes. Because carpenter ants tunnel in wood to build their colonies, an infestation can cause serious structural damage if left unchecked.

When are carpenter ants most common?

You are most likely to see swarms of winged (reproductive) carpenter ants in May and June as this is their mating season.

Where am I most likely to find carpenter ants?

Carpenter ants prefer moist areas and may construct their nests anywhere in the home including walls, ceilings, attics, doors, sills, shingles and insulation. Carpenter ants are most active during the night when they forage for food.

Are carpenter ants hazardous to humans?

Yes. Since carpenter ants are attracted to foods such as honey, jelly, fruit and meat, they can carry disease germs from one area to another. Although they do not sting, they can inflict bites.

What are their breeding habits? Do they multiply quickly?

Carpenter ants are social insects, living in colonies. Within the colony, winged reproductives are not produced until the colony is established, which takes about two to three years. After mating, the winged reproductives leave the colony to establish new ones. Once established, an average colony contains 2,000 to 3,000 carpenter ants.

Do weather conditions affect the size of a carpenter ant infestation?

Yes. Warm, moist weather presents ideal conditions for carpenter ant colonies to establish themselves.

How can I tell if I have a carpenter ant infestation on my property?

The presence of worker ants in your home is one of the first indications of an establishing carpenter ant colony. Check all areas where you suspect moisture. The presence of frass (chewed wood similar to sawdust) is an indication of an active nest. Any flying insect in the home is cause for concern and a professional in pest control should be consulted.

What can I do to prevent an infestation of carpenter ants?

The elimination of moist conditions by providing good ventilation and isolating wood from any direct contact with the soil will aid in carpenter ant prevention. Foods should be kept in sealed containers and areas where food is stored kept free of spillage or crumbs. Eliminate old lumber, logs and stumps from around your property and do not store firewood inside the building. In the case of new construction, only properly treated lumber should be used.

If I have an infestation of carpenter ants, what can I do to eliminate them?

Both the detection and elimination of carpenter ants can be a difficult and lengthy process. It is recommended that an Abell service technician be contacted to eliminate pests such as carpenter ants.

Preparation Guidelines for a Carpenter Ant Treatment

Step 1 - In areas where ants are seen and in particular the kitchen, empty bottom of cupboards and the bottom of closets. Dishes and food should be kept out of the way.

Step 2 - If ants are seen in the washroom, the vanity should be emptied.

Step 3 - Sometimes it is necessary for the Abell Service Technician to drill into walls and ceiling areas to access a carpenter ant nest. Holes will be sealed at the time of service.

Step 4 - If bait stations are used during the time of service, they should be left where the Abell service technician places them. Please do not disturb.

Step 5 - Vacate the premises during service and do not re-enter until at least 4 hours after treatment. Persons with underlying health conditions should consult their family physician where they have concerns regarding re-entry. Open windows for 20 to 30 minutes after re-entry is possible.

If you have any questions, we would be happy to help - please call your local Abell Pest Control office, 1-888-949-4949.