Garden Guide

What the buzz is all about — carpenter bees
May. 28, 2014 @ 04:58 AM

One of the negative consequences of this beautiful spring weather is the emergence of pesky carpenter bees. Carpenter bees, also known as Xylocopa virginica, are large bees that tunnel into wood to make their nests. Carpenter bees do not eat wood, but instead feed on pollen and nectar like many other bee species.

Carpenter bees closely resemble bumblebees, but have nearly hairless and shiny abdomens, which are unlike the hairy abdomen of bumblebees. Also, male carpenter bees lack a functioning stinger, but can be territorial and often buzz at people who approach their nest causing unnecessary fear. Female carpenter bees have the ability to sting, but rarely do so unless provoked or handled.   

Carpenter bees are beneficial pollinators, but can be considered a pest when they damage people’s property. In the wild, carpenter bees use logs, trees and stumps to construct their nests. Unfortunately for the homeowner, they will also make their nests in decks, siding, wooden trim and wooden lawn furniture. The bees bore almost perfectly round half-inch hole into wood against the grain. Then the female carpenter bee makes a 90-degree turn and borrows with the grain for several inches — in this section, she makes cells in the tunnel and lays eggs.

Predators such as woodpeckers who then open up the hole even more to feed on the developing bees can exaggerate carpenter bee damage. Carpenter bee damage is generally only cosmetic, but repeated nesting’s can cause serious damage to wooden structures. Also, the bees defecate on the outside of wooden structures beneath their hole, which can stain the wood and generally be an eyesore.

Prevention is the first step in avoiding problems caused by carpenter bees. In order to deter bees from nesting in your wooden structures, paint or varnish all exposed wood. Also, use hardwoods when possible as carpenter bees prefer to nest in softwoods. Powdered insecticides such as sevin dust work best to eliminate carpenter bee infestations. Wait until nightfall when the bees are asleep inside their nest and use a hand duster to apply the insecticide to the inside of the nest. Wait several days for the bees to spread the dust around their nest and die. Once the bees are eliminated, cover their hole with wood putty or a wooden dowel. Bee and wasp spray is also effective at controlling carpenter bees. With the proper prevention tactics and management practices, one can keep carpenter bees from causing problems and be more able to enjoy this beautiful spring. 

For more information on carpenter bees, contact N.C. Cooperative Extension, Lee County Center (919-775-5624).

Alec Check is a Horticulture Intern for N.C. State University.