What are Carpenter Bees?
Carpenter bees get their common name from their habit of boring into wood. Carpenter bees do not eat wood but cause damage to structures by drilling circular holes to create tunnels inside the wood. Unlike other common bees, such as honeybees and bumble bees that live in colonies, carpenter bees are not social insects and build individual nests into trees outdoors or into the frames, eaves or sides of buildings.
During the spring, people often notice large, black bees hovering around the outside of their homes. These are likely to be carpenter bees, named for their habit of excavating holes in wood, in order to rear their young. Carpenter bees prefer unpainted, weathered wood, especially softer varieties such as redwood, cedar, cypress and pine. Painted or pressure-treated wood is much less susceptible to attack. Common carpenter bee nesting sites include eaves, rafters, fascia boards, siding, wooden shake roofs, decks and outdoor furniture.
Carpenter bees name
Carpenter bees are named for their incredible nesting method: drilling tunnels into old wood. A common misconception, these bees don’t actually eat wood—they excavate it with their razor-sharp mandibles, leaving tell-tale deposits of sawdust beneath the entrance of their nest. They prefer bare, unpainted, or weathered softwoods, and are especially fond of redwood, cedar, cypress, and pine.
Carpenter bees Description
Carpenter bees are about 1/2 to 1 inch long and robust. They look like bumble bees, but the top of the abdomen is bare and shiny. Bumble bees have a hairy abdomen. Carpenter bees bore into wood particularly porch, garage and shed ceilings and trim, railings, decks, etc. The resulting holes are almost a perfect circle about a 1/2 inch across. Inside the tunnels will branch repeatedly. Carpenter bees do not eat the wood they tunnel in. They feed on pollen and nectar. The female carpenter bee has a dark face and can sting, but seldom does. The male has a yellow face, and may buzz or fly aggressively around your head and home, but cannot sting.
Biology and Habits of Carpenter bees
Carpenter bees do not live in colonies like honeybees or bumblebees. The adults overwinter individually, often in previously constructed brood tunnels. Those that survive the winter emerge and mate the following spring. Fertilized female carpenter bees then bore into wood, excavating a tunnel to lay their eggs. The entrance hole in the wood surface is perfectly round and about the diameter of your little finger. Coarse sawdust may be present below the opening, and tunneling sounds are sometimes heard within the wood. After boring in a short distance, the bee makes a right angle turn and continues to tunnel parallel to the wood surface. Inside the tunnel, about five or six cells are constructed for housing individual eggs. Working back to front, the bee provisions each cell with pollen (collected from spring-flowering plants) and a single egg, sealing each successive chamber with regurgitated wood pulp. Hatching and maturation occurs over several weeks, with the pollen serving as a food source for the developing larvae. Later in the summer, the new generation of adult bees emerge and forage on flow
Carpenter bees Life Cycle
Young adult male and female bees hibernate in the tunnels during the winter. They mate in the spring and set about to clean out and enlarge the old tunnels or to excavate new ones as brood chambers for their young. Each chamber is provisioned with a portion of “bee bread”, a mixture of pollen and regurgitated nectar, which serves as food for the larvae. An egg is deposited on the food supply and each chamber is sealed off. There are typically 6 to 8 chambers created by the female. The larvae that hatch from the eggs complete their development and pupate. Newly developed adult carpenter bees emerge in August, feed on nectar and return to the tunnels to over-winter.
How To Get Rid of Carpenter bees
Control and Prevention Carpenter bees
The best time to control carpenter bees is before tunnels are fully constructed. Liquid, aerosol or dust insecticides containing ingredients such as bifenthrin, cyfluthrin, deltamethrin or lambda cyhalothrin can be applied directly into tunnel openings. Leave the holes open for a few days after treatment to allow the bees to contact and distribute the insecticide throughout the nest tunnel. Then plug the entrance hole with a piece of wooden dowel coated with carpenter’s glue, putty, or other suitable sealant. This will deter future bees from using the old tunnels, as well as moisture intrusion and wood decay.
Once the inspection is complete, the pest control plan is prepared. The most effective control method is to apply an insecticide dust to the bee’s drill holes and leave the holes open for a few days so returning bees will contact the insecticide.
Once the bees die, the drill holes can be sealed and repainted. Sometimes it may also be useful to apply an aerosol spray to control free flying carpenter bees. While only a temporarily effective method, applying a liquid insecticide to the wood surface is a less time consuming process than applying dust to drill holes. A control technique that does not use insecticides is to paint any bare, exposed wood surfaces that are being attacked with exterior paint or a polyurethane finish. Your PMP will also inspect for weathering that will make it likely that the bees will attack. Also, your PMP may recommend sealing existing bore holes to discourage bees that are searching for possible nesting sites.