By  Grady Sampson
Homeowners often mistakenly refer to carpenter bees as bumble bees because of their similarities in size and appearance.  But carpenter bees nest in excavated wooden tunnels while bumble bees nest in the ground. The carpenter bee can also be identified by having bright yellow, orange or white hairs on the thorax and a black shiny abdomen. Bumble bees have hairy abdomens that are black or yellow in color.
Unpainted, exposed wood is especially attractive to carpenter bees. The most effective deterrent to carpenter bee activities is a painted (oil base or polyurethane) surface.  Unfortunately, painting or placing polyurethane on many wood surfaces such as decks or log homes is not attractive or practical for most homeowners. Wood stains provide little repelling action.
If control is necessary, spray liquid insecticide on wood surfaces to reduce carpenter bee activity. The expected residual effectiveness of these insecticides on exterior surfaces is less than thirty days, so re-application may be necessary for long term control.
Established bee galleries should be sprayed with liquid insecticides late evening or at night when the bees are inside the wood tunnels. After twenty-four hours, all tunnel entrances should be plugged with a wooden dowel coated with wood glue or steel wool covered with caulk to prevent re-colonization by other nesting bees.
Carpenter bees are important pollinators and are only nuisance pests in most cases. If they are not causing serious problems, they can be left alone.