Sitting out on your patio, you see a rather large bee that looks like it’s headed for the underside of your roof. What’s up with that? It may be a carpenter bee.
These large and robust insects resemble bumblebees. Females range from about 5/8 to 1 inch long and are shiny black or with metallic blue reflections. Their abdomens are shinier than those of bumblebees with fringes of hairs on some segments. Males usually have pale hair on the thorax and the male valley carpenter bee is golden brown.
Carpenter bees cause damage to wooden structures by boring into timbers and siding to construct nests. The nests weaken structural wood and leave unsightly holes and stains on building surfaces. Sound, undecayed wood without paint or bark is usually selected for nests. Carpenter bees also frequently attack dead wood on trees or lumber from southern yellow pine, white pine, California redwood, cedar, Douglas fir, cypress, mimosa, mulberry, ash, and pecan trees. They avoid most hardwoods.
The presence of carpenter bees around buildings and wooden structures can be annoying or even frightening; however
Prevention is the main approach to managing carpenter bees. On all buildings, fill depressions and cracks in wood surfaces so they are less attractive. Paint or varnish exposed surfaces regularly to reduce weathering and attack by bees. Fill unoccupied holes with steel wool and caulk to prevent their reuse. Wait until after bees have emerged before filling the tunnels. Once filled, paint or varnish the repaired surfaces. Protect rough areas, such as ends of timbers, with wire screening or metal flashing.
Carpenter bees are generally considered beneficial insects because they help pollinate various plants. Males cannot sting and females sting only when provoked or handled roughly.