How to Get Rid of Carpenter Ants

Carpenter ants are social insects known for boring galleries into wood. Unlike termites, they cannot actually digest the wood - instead it is displaced for the purposes of shelter. They are a nuisance pest respoonsible for causing unsightly aberrations in decking and wood framing. They prefer dead moist wood to live trees because tree sap acts as a natural insecticide. Carpenter ant activity peaks around May and June each year and will sustain itself until winter (or longer depending on levels of heat and sunlight). Though not nearly as aggressive, their bite is often compared to that of a fire ant.

Carpenter Ant Identification

Carpenter ants are easy to identify based on their size. They are relatively large compared to other ants, sometimes an inch in length. The most common species is the black carpenter ant, who is very dark in color. In some cases you may even find them indoors with wings. Their goal is to leave the nest in search of a mate, but their presence inside the home often represents the overflow of an already established colony. This group of winged flying ants is known as a swarm.

Getting Rid of Carpenter Ants in the House

The presence of carpenter ants is often accompanied by ambiguous piles of sawdust or woodshavings alongside decking or windowsills. This is a combination of wood debris and frass (fecal waste) from tunneling ants and is the first sign of an infestation. Use the wood shavings to trace the problem to the source. Normally, carpenter ants can only bore galleries into wood rich with moisture. Performing a throughough inspection on the property is the best way to locate any areas or framing with moisture or drainage problems, potential locations of the nesting site. Carpenter ants are most active between spring and fall.

Using the butt-end of a screw driver, you can tap around windows and doors in search of soft wood. The vibrations from the screwdriver will aggravate the colony and they will be quick to respond.

Infestations are not always limited to floor levels. Roof gutters clogged with leaves and other debris will quickly soften the eaves around your home. Piles of leaves, rotiing stumps, log piles, and mulch also make excellent nesting sites. Carpenter ants have also been know to travel on telephone lines and home wiring.

Natural Carpenter Ant Control

There are many natural techniques to get rid of carpenter ants. If possible, remove the source of the infestation - in cases where the wood cannot be removed, baits are an excellent choice.

Consider using water based tuna or sandwich meat to outline the colony source. The food will quickly be collected and taken back the source of the infestation.

Terro, a popular ant bait containing boric acid, is a sweet bait suitable for use against carpenter ants. It should be placed in small quantities around the nesting site. Workers will carry the bait back to the queen and it will destroy the colony in a matter of days. Carpenter ants are most active just after sunset and can travel over 100 yards in search of food. White vinegar in a spray bottle can also be used as a natural solution to discourage recurring carpenter ant infestations.

  • Search for the source. Inspect fencelines, wood framing, plumbing lines, and windows for foraging carpenter ants and wood shavings. Place baits in dry shaded areas along any trails.
  • Shrubbery and bushes should be cut at least a foot from the home. It's also a good idea to remove any overhanging tree branches. Tree stumps infested with carpenter ants should be destroyed or removed.
  • Correct any problems with moisture or drainage. Carpenter ants can only thrive in wood that is heavy in moisture. Correct any known leaks or look for pooling water outdoors.
  • Dust infested wood lightly with boric acid. When you have located the source of the colony, an application of boric acid directly into the gallery will eliminate the problem.

If applicable, screens should be removed from infested windows to prevent further accumulation of moisture. If the infestation is indoors, baits should be placed in electrical outlets surrounding the afflicted area. Boric acid by itself can also be applied in outlets and doors surrounding afflicted areas. The carpenter ants will disappear after a few days and the galleries can then be sealed with caulk. While permanent carpenter ant damage is possible, they have never been known to cause extensive structural problems.

Professional Carpenter Ant Control

While baits are preferred, any product containing a residual insecticide labeled for carpenter ants can be used to supplement treatments. Cyfluthrin, the active ingredient in Cy Kick CS, has a strong reputation of repelling ants and many other crawling insects. It's a micro encapsulated product, meaning it lasts for about 30 days when it's sprayed.

  • Spray lightly around afflicted areas. Consider the range of the ants. Is there more than one nest? Carpenter ants can nest in decking, flowerbeds, and mulch.
  • Do not overlook points of entry. Ants will climb deck posts, hide beneath siding, and inhabit a multitude of locations. Do not place baits in areas that you have sprayed directly or you will taint the bait's allure, rendering it much less effective.
  • Less is more. The more insecticide you spray, the less likely it is you will destroy the queen. This is because the ants may die before making it back.

Insecticide can be directly injected into cracks and crevices along window sills and any wood galleries carved out by the carpenter ants. Spot treatments with repellent insecticides should only be done if baiting has failed to work. That's because repellents can cause ant colonies to split or double, a process known as budding.