How to Deter Carpenter Bees

Carpenter bees are solitary bees that make nests in wood. They resemble bumblebees, except their abdomen is bare and shiny black instead of hairy. Carpenter bees can sting, but are usually not aggressive. The female carpenter bee bores a perfectly round hole about the size of your thumb in a wooden surface, then bores out branches called galleries. The branches are packed with a ball of pollen on which the larva feed, and the adult bees emerge next spring to begin the cycle anew.

Paint or stain

Carpenter bee repellent

Wooden dowel

Wood putty

Insecticidal dust

Insecticidal spray

Paint or stain bare wood, or use pressure treated lumber. Carpenter bees are attracted to weathered, unpainted wood. They are less likely to attack pressure treated lumber, or wood that has been painted or stained. Paint is a more effective deterrent than stain.

Mix paints or stains with products formulated to repel carpenter bees. Follow the manufacturer's instructions for application.

Spray susceptible wood with insecticide sprays in the early spring when female carpenter bees are looking for new nest sites. You may need to repeat the treatment, since some sprays are only effective for a week or two.

Seal the hole using a wooden dowel and wood putty then repaint. Carpenter bees return to nest holes year after year.

Close doors to structures such as sheds and garages. Carpenter bees can attack exposed wooden beams inside.

Kill the larva in the holes using insecticidal dust before sealing them. You want to kill the larva first rather than just sealing the holes, because the adult bees that emerge can bore new holes to escape.

Female carpenter bees will sting when defending their nests, so treat any holes you find after dark. The adult bee will be inside the nest, and less likely to sting.