4 Sure-Fire Steps to Eliminate Carpenter Ants and Prevent Infestations

Carpenter Ant
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Carpenter ants can be very destructive to a home - or any other building, but how can you know if your house is infested and what can you do to get rid of this damaging ant?

1. Identify the Ant With a Magnifying Glass

Carpenter ants can be somewhat easy to identify, particularly if a magnifying glass is used. But to do this, you have to first catch one of the quick insects so that you can hold it still under the magnifying glass to examine it.

Here's how to catch and examine an ant:

  • When you see ants you believe may be carpenter ants, use your fingernail, finger, or another small object to flick one into a small plastic or glass container with a lid.
  • Place the entire container, with the ant, in the freezer for a few minutes.
  • Remove the container from the freezer and the carpenter ant from the container. Place the ant on a plain surface so you are are looking at its profile.
  • Look for two distinct characteristics:
    - First, carpenter ants have a smooth, rounded back with no humps
    - Secondly, these ants have a tiny pyramid or pedicel at their waist.
  • If you see these, you will know you are looking at a carpenter ant. Note: carpenter ants can be of various sizes - from very large to very small, so the size of the ant does not matter.

2. Determine if Carpenter Ants Are Infesting Your Home
Once you know what this species of ant looks like, and you have determined that it is this species that you are seeing in your home, you need to determine if it was just a chance entry by an ant or two, or if you have an infestation.

If you have an infestation:

  • You will see the ants in the home over a period of several days or weeks.
  • You may hear them scurrying about inside walls, especially at night.
  • You may see piles of sawdust, or frass, under the house, that workers have bulldozed from their nests. (Unlike termites, carpenter ants do not eat the wood they tunnel into, so they have to get rid of it somehow, thus the piles beneath the neat opening.)

    3. Take Control of Carpenter Ants with Least-Toxic Methods

    If you have determined that you do, indeed, have a carpenter ant infestation in your home, it's time to take action:

    1. Locate the nests by following the well-defined trails of the foraging carpenter ants at dusk or after dark. The ants will be going in both directions and those moving toward the nest may be carrying insects or bug parts for food. Carpenter ant nests may be outside the home in a tree stump or near an entrance/crack into a home.
    2. Treat outdoor nests by spraying a pyrethrin aerosol directly into the nest for at least 10 seconds. If a nest is within a wall void, drill a 1/8" hole and spray the same pyrethrin product through an injection straw. Alternately, diatomaceous earth and silica gels can be "puffed" into outside nests. The applicator should wear a dust mask to avoid inhalation of the product.
    3. If carpenter ants are still present in the home two weeks after the treatment, repeat the treatment. If carpenter ants remain active within a wall void, a carpenter can remove a section of the wall, then extract the nest and ants and repair the wall.

    4. Keep Carpenter Ants Out of the Home

    Now that you have eliminated the carpenter ants, the next step is keeping out new populations:

    1. Seal all cracks on the home's exterior including utility service entrances.
    2. Dry up leaks outside and inside the home and repair or replace any moisture-damaged wood.
    3. Chip stumps in the yard, ensuring that the wood debris is mulched or located far away from the home.
    4. Similarly, locate firewood piles away from the home, so that they do not touch the home or garage wall.
    5. Trim tree branches so that they do not touch the home, roof or attic.
    6. Maintain a clearance of six inches between wood siding and the soil to make sure that the siding does not "wick" moisture from the ground and provide ants another route into the home.

    Edited by Lisa Jo Lupo.