Pest Alert - Carpenter Bees

(Updated: April 26, 2024, 12:41 p.m.)

Carpenter Bees


carpenter bee nest in a wooden post

Every year carpenter bees tunnel into wood around homes. The female bee bores a half inch hole into wooden siding, porch rails, furniture, fencing, decking or whatever wood she can sink her mandibles into.

Female carpenter bees can live in their tunnel for years. Sawdust rains down as she expands her home each season. Eventually the tunneling can weaken the wood and cause safety issues with decks, barns and furniture. Woodpeckers will sometimes tear off the siding to get at the bee larvae further damaging structures.

Carpenter Bees All Bad?

Despite the insect’s propensity for destroying wooden structures, the carpenter bee is actually a beneficial insect in some ways. The female collects pollen and nectar from flowers thereby providing important pollinating services. I do not like to kill insects or any other creature for no reason. However, I have a saying; ‘You can’t let a critter destroy your home.'

carpenter bee resting in flower
Sometimes you can find carpenter bees resting in flowers.

Controlling Carpenter Bee Damage on Homes

So, how can you stop carpenter bees from boring holes into your wooden structures and furniture? I recommend a multistep approach. First, if you live in a highly susceptible home such as a log cabin, you should treat the wood with a preservative such as boron. Then use insecticides containing pyrethroid insecticides such as permethrin, deltamethrin, or bifenthrin applied to wood in the spring and again in the summer can protect wood. If you are uncomfortable or unable to do this work yourself, local home pest control companies will be glad to do it for you. A simple coat of high quality paint can prevent carpenter bee tunneling.

If bees have already bored holes in your siding, then a little insecticide sprayed around the entrance of the tunnel will get the female. As she leaves and enters her home, she tracks the insecticide into the tunnel eventually killing herself and her larvae. A little caulk and paint can repair the hole and protect the damaged wood from rot.

Male carpenter bees hover outside the female’s tunnel and defend it from other would-be suitors. The males swoop and threaten any passerby including people as they guard their mate’s home. It may sound silly but a tennis, badminton, or racquet ball racquet can be very effective at killing the male bees.