When people generally worry about wood in their home being damaged by insect pests, they think of termite infestations. However, termites are not the only insects that can infest and damage the wood in your house. In fact, there is a species of bee that is known for regularly bore into and damage structural wood, as well as other wooden materials. They have been appropriately referred to as “the living drill” by many homeowners. Unlike termites, the holes that carpenter bees bore into wood are actually nesting sites that they use to raise their offspring. They will drill these holes in everything from the handles of yard tools and lawn furniture to the eaves of homes or barns. No wood is safe from these guys, and can cause some serious structural damage to your home with these tunnels.
Carpenter bees neatly chew almost identical holes that are ½ inch in diameter into wood. It is the piles of fresh sawdust that they leave behind that provide the first clue that you have an infestation of carpenter bees. New holes are chewed first against the grain of the wood they are infesting before the bees turn at a right angle to then go with the grain. These new tunnels generally extend around 4 to 6 inches. But these living drills will also use old tunnels made by other bees and further extend these tunnels. This practice is what can cause some major structural damage, as some of these tunnels can end up being as long as 10 feet. It is this extensive and multiple tunneling that causes the kind of structural damage that makes infestations from these bees almost as worrisome as an infestation of termites.
While it was once thought that painting wood was an effective tool to guard against infestations of carpenter bees, it is now understood that the bees might prefer unpainted wood, but will infest painted wood if that is what is available. If you already have an infestation, using an appropriate insecticide in conjunction with liquid soap to fill in the tunnels effectively controls the adults and emerging young. You can also use a borate formulation such as Tim-bor or Bora-Care to help prevent infestations by applying it to existing structures and using borate pressure-treated wood to build new structures or replacing damaged wood. The borate crystal that this treatment develops in the tissue of wood will damage the mandibles of carpenter bees trying to tunnel into the wood, making them retreat and look somewhere else for the wood they need.
Have you ever experienced an infestation of carpenter bees? How did you handle it?