I have been receiving numerous calls the past couple of weeks about large bees drilling holes in wood — the culprit is the carpenter bee.
Carpenter bees are large, black and yellow bees often seen flying around wooden eaves of a house, wooden decks or wooden fences. They are usually mistaken for bumble bees, but are unlike bumble bees in that they have a black shiny tail section.
The carpenter bee got its name because of its ability to tunnel in wood with it jaws. The bees make ½-inch round holes in wood.
Sawdust can be found on the ground or on the surface of an object beneath the hole. The holes go a short distance into the wood and they run horizontally with the grain for at least six inches or more.
Several bees may use the same entrance hole and branch off in different directions from the main tunnel. The tunnels may go for several feet in the wood if the same entrance hole is used for several years.
Unlike termites, carpenter bees do not consume the wood as food. Instead, they gnaw tunnels to create nesting sites.
Carpenter bees overwinter in tunnels. They emerge from the tunnels in early spring. The female bees lay eggs in the tunnels until the tunnels are full. Male bees do not drill tunnels, but they are protective of their territory.
The male has a white spot on the front of the face that distinguishes it from the female. Female carpenter bees seldom sting, but when disturbed or handled they can inflect a painful sting. Male carpenter bees cannot sting, but they often become aggressive and frighten people when they fly about their heads. These adult bees die within a few weeks.
The larva of carpenter bees is large and noisy. The noise they make may attract woodpeckers. The woodpeckers will do further damage to wood in their hunting for the larva. If you see woodpeckers on the eave of your home, they are likely in search of the carpenter bee larva.
There are at least three methods that could be used to control carpenter bees: 1.) aerosol treatments of insecticides applied directly to adult carpenter bees; 2.) residual surface and gallery treatments with insecticides, and 3.) preventive treatments such as painting wood with thick coats of oil-based or latex paints.
Several days following treatment, after carpenter bee activity has ceased, holes can be plugged with dowel rods, plastic wood, caulk or with other suitable materials. If carpenter bees continue to attack the wood, additional residual insecticide treatments may be required at weekly or twice weekly intervals. Painting the wood with an oil-based or polyurethane paint will discourage the bees, but will not make the wood bee-proof.
Bill Tyson is the coordinator for Effingham County Cooperative Extension of the University of Georgia. E-mail him at email@example.com or call the Extension office at 754-8040.