Carpenter bees (Xylocopa virginica) resemble bumblebees size and appearance.

Each is one-half to one-inch long, with black and yellow body markings.

Most of the top of the abdomen of carpenter bees is without hairs and is shiny black in color.

While carpenter bees resemble the bumblebees, they are not social insects. They construct their nests in trees or in frame buildings.

Carpenter bees can be seen hovering near the eaves of a house or drilling in wood. Xylocopa virginica is the only species of the large carpenter bees encountered in Pennsylvania.

The male bee is unable to sting. It is the male carpenter bee that is seen hovering in the vicinity of the nest. They dart after any other flying insect that comes into their territory.

They will also approach people if they move quickly or wave a hand in the air. The female bee will sting when provoked.

Carpenter bees do not eat wood. They excavate the tunnels for shelter and as chambers in which to rear their young.

They will attack unpainted objects such as doors, windowsills, roof eaves, railings, telephone poles and pressure-treated wood.

A carpenter bee begins her nest by drilling a nearly perfectly round entrance hole of approximately one-half-inch in diameter into the wood. The hole is usually against the grain of the wood.

When the tunnel is about one-inch deep, the bee turns at right angles to the initial hole and tunnels with the grain of the wood.

Bees prefer to attack wood that is greater than two-inches thick. While the damage to wood from a single bee is slight, the subsequent year’s broods expand the tunnel through branching activities and can cause considerable structural damage.

To control carpenter bees, locate the hole in which the bees are active and apply an insecticidal dust directly into the nest opening. Use a duster that will puff the dust up into the tunnel and coat the sides.

To avoid possible stings, treat the area at night. If you must treat during the daytime, use a pyrethrum spray or wasp and hornet spray to knock down any bees flying about.

Do not plug the holes immediately. The bees must be able to pass through the nest opening where they will contact the dust and spread it through the tunnels.

It is best to treat in spring when the bees are first noticed, again in mid-summer, and a third time in early fall to contact any over-wintering bees occupying the tunnels.

In the fall, fill the holes with wood putty and the entire wood surface should be painted or varnished. Stained wood is not usually protected from attack.

Remember, pesticides are poisonous. Read and follow directions and safety precautions on the label.

Rain Barrel Workshop,

10-11 a.m. May 25, Walnutport Canal Association pavilion, Lehigh Street, Walnutport.

Penn State Extension Master Watershed Stewards and partners are offering the workshop.

Participants will construct their own rain barrel to take home. They will learn about topics such as stormwater management, best practices for homeowners, the anatomy of a rain barrel, maintenance tips, and how to properly connect it to their downspout. Cost: $60. Registration includes the cost of the barrel.

To register:

extension.psu.edu/rain-barrel-workshop-build-your-own

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613.