How to Kill Carpenter Ants

How to Kill Carpenter Ant

Carpenter ants can be difficult to control, the information provided is to help you get rid of and kill your carpenter ant problems.  Carpenter ants that enter the home are black and can vary in length from 1/4 to 3/4 inch. Unlike termites, all carpenter ants have narrow (or constricted) waists (they have a waistline) and elbowed (bent) antennae.

Carpenter ants are social insects, similar to termites and they  form large colonies. A mature carpenter ant colony may contain up to 3,000 individuals, but usually only one queen, but they can have satellite colonies.   Carpenter ants form nests in wood by tunneling against the grain. These galleries are free of mud and sawdust. Coarse sawdust is present below the entrance of an active nest.

Carpenter ants DO NOT eat wood; they do however remove the wood to create their galleries and tunnels.  They do however feed on sources of protein and sugar. Carpenter ants, outdoors feed on living and dead insects, they are also very attracted to honeydew, a sweet liquid produced by aphids and scale insects. Most foraging is done at night between sunset and midnight during spring and summer months. This is the best time to locate a colony, entry points and to apply baits.  Sometimes workers travel up to 100 yards from a nest in search of food.

Larvae of Carpenter ants

Carpenter ants nest in moist wood including rotting trees, tree roots, tree stumps, and logs or boards lying on or buried in the ground. They can also nest in moist or decayed wood inside buildings. Wood decay may be caused by exposure to leaks, condensation, or poor air circulation. Nests have been found behind bathroom tiles; around tubs, sinks, showers, and dishwashers; under roofing, in attic beams, and under subfloor insulation; and in hollow spaces such as doors, curtain rods, and wall voids. Carpenter ants may also nest in foam insulation.

Many foods are attractive to carpenter ants, including honey or other sweet foods. During spring, carpenter ants are particularly attracted to protein sources, such as tuna packed in water. (Carpenter ants are not attracted to tuna packed in oil.) Set out small pieces of tuna for the ants to take back to their nest. It is easier to follow the ants when they are carrying food. With patience and perseverance, you can follow the ants back to their nest.

Other signs that indicate an active nest is nearby include small piles of coarse sawdust or wood shavings, consistent indoor sightings of large numbers of worker ants, i.e. 20 or more, and large numbers of winged ants indoors. Carpenter ants typically swarm from late winter through spring.

Also pay attention to areas where steady moisture is or has been a problem; firewood stored in an attached garage, next to the foundation, along an outside wall, or in a basement; areas around the plumbing or vent entrances; and trees with branches overhanging the house. These are possible sources of carpenter ant nests.

Sound detection may be helpful in locating a nest. An active colony may make a dry, rustling sound that becomes louder if the colony is disturbed. This sound, thought to be a form of communication, is made with the mandibles (jaws) and is not related to wood chewing. When trying to detect carpenter ants, tap the suspected area and then press an ear to the surface in order to hear any sound.

If one nest is found, watch for evidence of additional nests. More than one nest may be present in a structure.

Where to look for Carpenter Ants Indoors:

Nests are often concealed in wall voids, ceilings, subfloors, attics, or hollow It is best to determine the nest’s location as specifically as possible but bait can be simply placed in the areas that the ants are moving about.

Black Carpenter Ant

Black Carpenter Ant

If you are able to see the nest and colony then using a liquid or aerosol insecticide will help destroy the colony.

Liquids or aerosol ready-to-use insecticide, such as bifenthrin, cyfluthrin, deltamethrin, or permethrin are labeled for use on Carpenter Ants.   Spray the insecticide directly into as much of the nest as possible

If the nest cannot be located, baits may are an effective alternative. Baits work by combining their attractive food source with a slow-acting insecticide. Maxforce and Advance Carpenter ant baits will be easily shared with colony and the delayed effect will all time for all ants to consume some of the bait, so that the colony is eliminated.  Food Sharing with social insects makes baits a very effective option for control.

The keys to successful baiting are placement and monitoring, if you do not put the bait out where the ant will never find it you will not be successful.

Do the insepection of your home and look for cracks in foundations, attic vents, plumbing penetrations, electrical wires that enter the home, branches that hang over roof line and touch can be a good entry point for carpenter ants.  Look for areas of the home that have excessive moisture problems, maybe where the gutter floods water to close to the wood.

Treat your Carpenter Ant problems with an appropriately labeled pesticide such as Advance Carpenter Ant Bait, Suspend SC, Talstar Concentrate or Cynoff.

Advance Carpenter Ant Bait is ant bait that can be placed in small piles in the ants traisl or can also be used as a scattered bait around piles of wood, around structures or in the home

A few excellent pesticides that are labeled for Carpenter Ant Control  is Suspend SC, Talstar Concentrate, Termidor and Cynoff.  These will also work for other insects.

Monica Bird (922 Posts)

Monica’s compassion for her customer's struggles with pest control issues and passion for pest control stems from over 10 years in the industry. With a master’s degree in entomology, she uses her knowledge and experience in chemistry, insects and pests to educate her customers.


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