Stopping Carpenter Bees

Warm spring weather is here and with it the insect world reawakens. The carpenter bee or boring bee, so named because of the ½” diameter hole that they make in wood, also comes to life and starts looking for a site to start a nest.

The adult carpenter bee resembles the common bumblebee but has a shiny bluish-black abdomen, where as bumblebees have a hairy abdomen that is mostly yellow. They have a preference for certain softwood species, including southern yellow pine, white pine, cedar, redwood, Douglas fir and cypress. They overwinter in the wood, emerging in late April through June, find a mate, and search for a nest site. The female bores a new tunnel or cleans out an existing one. She bores into the wood approximately 1 inch then turns 90 degrees and tunnels another 4 to 6 inches and lays her eggs, starting the next generation.

Carpenter bees tend to return to the same area that they emerged from. Look for small amounts of sawdust on the logs and ground, which result from the boring. The hole, approximately ½ inch in diameter and almost perfectly round, is usually found up near the eaves or upper logs. When you find that the bees have started a nest you need to stop the bees and plug the holes.

The best control is to put a finish on the raw wood before the bees find the wood. Bees prefer unfinished wood but will bore and nest in stained wood. Special additives can be used with the finish to deter bees. We offer NBS30 (natural botanical) repellent, which is mixed in with the finish. There are other chemical products that can be put on or in the bored hole area to control their presence. Another method is to run a length of flexible wire into the tunnels to destroy the bee and larve, and then the hole can be filled with steel wool and caulked.

By being aggressive about detering carpenter bees, you can control their presence.

Fred Hathaway, Purchasing Manager