Carpenter bees are wood-boring bees. They are similar in coloring and appearance to bumble bees. Homeowners may notice the bees themselves or their holes, which have a perfectly drilled appearance. The bees bore tunnels into wood in order to lay eggs, and young bees spend the winter living inside the holes. Frequently, the bees nest in wood used on and around homes, including wood trim around windows, decking and patio furniture. Carpenter bees prefer bare wood and weathered wood for their nesting sites, and may return to the same holes or the same wooden structure. Only the female bees sting, but they rarely sting unless molested by humans; male bees may act territorial and aggressive, but they cannot sting.
Close your doors. Bees mate and begin to search out nesting sites in late spring and early summer. During this period, you should prevent the bees from gaining access to the interior of any garage or shed where the bees may damage unfinished wood.
Use woods not preferred by the bees, such as hardwoods. Carpenter bees show a preference for redwood, cedar, cypress and pine, according to the University of Kentucky's Entomology Department.
Paint the wood on your property, focusing on the pieces you wish to keep bees from damaging. This is the best option for wood already in place, as it spares both humans and bees. A coat of paint will also deter bees from visiting an item previously damaged by tunneling. The Clemson Cooperative Extension suggests using an oil-based paint.
Finish wood, if you prefer not to paint. Stains and preservatives do not repel the bees to the extent that painting will but a finished wood is less vulnerable to tunneling bees than bare wood.
Apply insecticides as a preventive measure such as carbaryl, chlorpyrifos or a synthetic pyrethroid. These are short-term solutions, lasting only a week or two, and may need to be reapplied.
Treat the tunnels with insecticidal dust in spring, midsummer and early fall. Leave the holes open during treatment, so that the bees will carry the dust deep within the nest.
Plug the tunnels in early fall using wood putty or by gluing wooden dowels or wood pegs into the holes to prevent the bees from reusing the tunnels. As an alternative, you may choose to remove sections of wood damaged by tunnels.