Carpenter Bee

This week we had a surprise visitor in our office, a Carpenter bee. An individual brought in a chunk of cedar branch with the large (1/2”) diameter holes in it as you can see in the picture. The next morning this little lady was watching us out of one of the holes in the branch. These bees are native to Kansas and can be both a wonderful pollinator and a pest for homeowners. Carpenter bees are often mistaken for bumble bees because they are similar in size and appearance however carpenter bees have a smooth, shiny abdomen while bumblebees are very fuzzy. You can also tell them apart by their nesting habitats. Carpenter bees’ nest in cavities and tunnels they create in the wood while bumble bees nest in colonies underground. Carpenter bee queens will excavate a series of tunnels approximately ½” in diameter in dead logs, stems or other wooden structures, including wooden siding or wooden decks, to create chambers to house their young. This nesting habit can put them at odds with humans as they can be destructive to homes and decks over time. The female bees can excavate an inch of tunnel a day and each succeeding generation will often use the same nest slowly creating a large elaborate tunnel system. If the nest becomes big enough there can be multiple queen bees using it. There will still be one “primary” queen which lays eggs and forages for food while the “subordinate” queens defend the nest. These bees typically live for one year however in large nests subordinate queens can live up to three years since they aren’t doing as much labor. Adult carpenter bees overwinter in the nest and start foraging sometime in April.

Carpenter bees are an important native pollinator however they can become a pest of homeowners in some situations. If bees start to use your home as a nest there are a couple options. First treat the wood with a paint or stain as this can deter bees from constructing a nest in your location. You can also provide alternative nesting solutions in your area such as untreated pine or cedar to lure female bees away from structures. If there is already a nest on the site paint will not deter them. Carpenter bee traps are available to relocate bees to a new location far away or insecticidal treatments may be the only option. The best method of treatment is to spray the tunnels at night with a bee and wasp spray to immobilize the bees. Another option is to us an insecticide formulated as a dust to puff into the tunnels. Fill the tunnel with caulk or a wooden dowel several days later to ensure another bee doesn’t take advantage of the already built tunnels. Paint the covered hole if possible to further deter bees.

Have questions? Contact our office where our Horticulture Extension Agent will assist you with questions.

Phone: (316) 321-9660

Email: callae@ksu.edu