Carpenter Ants in California

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Carpenter Ants Biology, Identification and Control Solutions

Although ants do not generally damage wood structures, there is one type of ant that likes to excavate the wood and create a dwelling out of this. Carpenter ants do not eat the wood, they only carve it using their strong jaws. Their galleries usually look like they have been sanded finely and most commonly can be found in the soft, decayed or infested portions of the lumber. They can be found practically in the majority of the United States (yes, that includes San Diego, CA), from sea level to over 9,000 feet high. Carpenter ants vary greatly in size, but on average their workers are around 5 to 10 mm, while queens can get as big as 12 to 16 mm. This unusual size makes them one of the largest species of ants in the continental United States. Normally a Carpenter Ant colony will be started by one queen, which will lay ‘ant eggs’ that will later become small workers. These workers main job will be the feed the queen so that she can keep expanding the colony.

The Carpenter Ant is a “single-node” ant, which means that they normally will not cause a stinging sensation with the irritating fluids they eject. They as well have only one “bump” or raised node on their waist which is located between the abdomen and their thorax. This waist as well serves as a primary differentiator of ants and termites, as termites have a broadly joined waist.

What are the first signs of a Carpenter Ant infestation?

The first signs of an infestation will commonly be a pile of sawdust-like debris, also known as “carpenter ant frass”. This frass is not fecal matter but just the wood debris that it’s left behind from carving into the wood.

Here is a photo to help you identify it *

Carpenter Ant Frass

Other signs might include:

  • The presence of swarmers (flying ants) emerging during warm days.
  • The presence of ant foragers, normally on the interior of the structure during night hours.
  • The presence of the remains of insects/bugs in the frass.
  • A soft, muffled cracking sound within the walls or wood members.

Why are Carpenter Ants a pest?

Although they are an important element to the environment, they can create extensive damage to your property especially here in San Diego, California as most properties are build using lumber. As part of our eco-system, Carpenter Ants are important predators of other bugs, recyclers of organic debris and decomposer of dead trees. However, as our properties are built with these trees it makes them incompatible with their biology. They can and will – if left undisturbed for a prolonged period of time – create extensive damage due to their natural tendency to carve their tunneling systems.

How can Carpenter Ants be controlled?

The most important step in controlling Carpenter Ants is to locate their nesting site and to destroy it. This can be located inside of the structure, or if you are a bit luckier it can be located on the exterior of the structure (sometimes hundreds of feet away). On the exterior they are commonly found on telephone/power line timber posts, tree branches, firewood (a big one) and other exposed timber especially if it has termite or rot damage. If the exterior nest is found and destroyed, treatment with a general pesticide labeled for Carpenter Ants is to follow to exterminate the remaining population. If the nest is to be found on the interior of the property and it cannot be eliminated, then treatment with a dust formulation is the most effective as it can be blown into the interior cavities of the nest and it will as well have the longest residual.

Do not take any chances if you believe that you have an infestation on your home or place of business. Give us a call today at (619) 421 – 2101 or send us a message online so that one of our expert technicians can evaluate your situation and provide you with the most effective solution for your case. We have the experience, the equipment and the chemicals necessary to control the problem in a safe way so that the damage and nuisance stops.

As well if you have any questions or comments about this post or any other pest please feel free to let us know so that we can assist you in answering/resolving them.

* = Photo courtesy of UCR Urban Entomology at

Gilberto A. Cortez
California Licensed Operator and Contractor

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