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Eastern Carpenter Bees
Name: Xylocopa virginicus (Linnaeus)
Family: Xylocopidae

Eastern carpenter bees are approximately one inch long and often mistaken for bumble bees. The latter have wide, hairy, yellow bands in the middle of the abdomen. By contrast, the abdomen of the large carpenter bee is shiny and black with few (if any) hairs or yellow bands. Females can sting if they are disturbed. Their pollination ability is questionable-they can remove nectar without pollinating the plant by cutting small holes in flowers. Unlike females, males have a large yellow/white spot on the front of the face and are stingless. Large male carpenter bees can be highly aggressive when defending their territory.

Biology
There is one generation of carpenter bees produced per year. Adults emerge from old tunnels in April or May and mate. Females then dig a tunnel, dropping sawdust on the ground under the hole. The tunnel entrance is almost a perfect circle. Wood piles, unpainted fence posts, fascia boards, eaves and decks are the preferred places of attack, and soft woods are favored over hard woods. The tunnel is perpendicular to the wood surface for the first one to two inches, makes an abrupt right angle turn, and then runs parallel to the grain of the wood for four to six inches.

Unlike many social wasps and bees, which feed their young on an as-needed basis, the large carpenter bee is a "mass provisioner" that lays an egg and fills the tunnel with enough pollen for the larva to complete development. She then seals off the chamber by making a thin wall from chewed wood pulp. The process is repeated five to seven more times in the same tunnel.
Adults emerge in August, overwinter in the tunnel and the cycle is repeated. Old tunnels may be reused or extended further into the structure.

Control
Structural damage is rarely serious, and large carpenter bees are more of a nuisance to homeowners than a serious threat. Painting, applying metal flashing or applying wire screening to the exposed wood surface are the best means to prevent infestation. Preventive sprays of bendiocarb, carbaryl or chlorpyrifos can be applied weekly or bimonthly to prevent attack. Active nests can be treated by spraying a labeled aerosol or by applying a dust to the inside of the tunnels. As with most stinging insects, nest treatments should be made at night. Always wear full protective gear (especially a bee veil) when treating nests. The entrance should be closed a few days later using wood putty or by gluing a piece of a wooden dowel rod in place. Paint over the dowel rod to prevent re-infestation.
Always follow the instructions on the pesticide label.

Contributed by Colin Stewart, a Ph.D. candidate working with Dr. S. Kristine Braman at the University of Georgia, Athens, Ga. His research emphasis is in landscape integrated pest management (IPM).

Copyright © 2001 [Alan Luke]. All rights reserved.
Revised: 06/25/10. Home