Hugh Cairns: Carpenter ants

Carpenter ants nest in wood, cavities or soft materials. They excavate galleries in wood or other materials by chewing and discard the debris (called frass) outside the nest. Frass often looks very similar to saw dust. Frass may sometimes be found under a hole or other opening but is often discarded unseen inside wall voids. Photo: Contributed – (Photo: Hugh Cairns)

Carpenter ants are the most visible—and perhaps the most intimidating—of the wood destroying pests encountered in the Okanagan.

Carpenter ants, as their common name suggests, are wood workers and classified as a wood destroying insect. Unlike their termite counterparts, Carpenter ants do not eat wood, but rather they bore or mine wood out wood to create galleries to nest in order to expand their colony. They excavate galleries in wood or other materials by chewing but they discard the debris (called frass) outside the nest. Frass often looks very similar to saw dust. Frass may sometimes be found under a hole or other opening but is often discarded inside wall voids.

In a house, Carpenter ants can inflict serious damage to structural framing components. Damp conditions inside of the walls of a building can attract Carpenter ants. Their primary interest in locating within a structure is to use it as a nesting site. They prefer wood, but it’s interesting to note that they don’t seem to care what kind of building material they nest in as long as it is in close proximity to a food and a moisture source. Sometimes their nests can be found in insulation materials rather than wood. The danger is that the inevitable expansion of the nest will lead them to move into adjacent wood components.

I can tell you from experience that once Carpenter ants have infested a structure, remediation is best left to the pest control professional. I see ant traps and home remedies frequently. This type of action can simply cause the colony to relocate, and in some cases make extermination more difficult. Colonies embedded in insulation, wood framing, or flat roofs lacking attic access can be particularly difficult to eradicate.