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How to identify it
- Large and robust like bumble bees, about 5/8 to 1 inch long, with a shiny, mostly hairless black abdomen.[1][5][2]
- Males have white or pale markings on the face and often pale hair on the thorax.[5][1]
- Ohio State notes a carpenter bee's head is about as broad as its thorax, while a bumble bee's head is distinctly narrower.[3]
- Entrance holes are perfectly round, about the width of a little finger (1/2 inch), often with coarse sawdust below.[2][1][4][5]
- Males hover in front of people near nests and chase other flying insects, but cannot sting.[2][1][4]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Bumble bee | Hairy, black-and-yellow-striped abdomen; nests in existing cavities, often underground in old rodent burrows, rather than tunneling into wood.[2][3][5] |
Where it lives
They prefer unpainted, weathered softwoods such as redwood, cedar, cypress and pine, attacking eaves, fascia, siding, decks and outdoor furniture; painted or pressure-treated wood is much less susceptible.[2][1]
Biology and life cycle
A female bores a short entrance about an inch deep against the grain, turns at a right angle and tunnels along the grain.[4][5][2]
She builds a row of cells, each stocked with bee bread (pollen and nectar) and a single egg and sealed with chewed wood pulp. Kentucky counts about five or six cells; Penn State and Clemson say six to eight.[2][4][5]
Development from egg to adult takes about 3 months. New adults emerge in late summer (Penn State says August), feed on flowers, and return to tunnels to spend the winter; they mate the next spring.[1][4][2]
They don't eat wood; the tunnels are only shelter and brood chambers.[4]
In the United States, large carpenter bees occur across the South from Arizona to Florida and in the East north to New York. Penn State says only one large species, the eastern carpenter bee, occurs in Pennsylvania.[6][4]
They are pollinators; the Forest Service says they buzz pollen loose from flowers and are excellent pollinators of eggplant and tomato, and UC IPM calls them generally beneficial.[6][1]
Damage and signs
- Tunnels are usually 6 to 10 inches long but can extend up to 10 feet when reused over many years, weakening timbers.[1][5]
- Holes let in moisture that leads to rot and decay.[2]
- Bees often defecate on the wall below the entrance, leaving stains.[4][5][1]
- Penn State says they prefer wood more than 2 inches thick; Clemson says vinyl siding and other non-wood surfaces aren't damaged.[4][5]
Health risk
Males can't sting. Females can sting painfully but seldom do unless handled or provoked, and carpenter bees are less inclined to sting than bees and wasps that live in colonies.[2][1][4][5]
Control
Prevention
Paint or varnish exposed wood, use hardwoods where possible, and cover rough timber ends with screening or flashing.[1][2]
Clemson recommends oil-base or polyurethane paint; stains give little protection.[5][2][4]
Keep garages, outbuildings, doors and windows closed in spring while bees search for nest sites.[2][5]
Keep them out
After bees have left, plug empty holes with steel wool and caulk, wood putty or a glued dowel, then paint over the repair.[1][5]
Traps and physical control
Traps, small wooden boxes with 1/2-inch holes over a clear bottle, hung near nesting areas in early spring can reduce drilling.[2][5]
Pesticides
Insecticides usually aren't needed. If damage risk is high, dusts labeled for carpenter bees can be applied into holes in early spring or fall when adults are inside; treating active nests in summer does little because sealed brood cells block the dust.[1]
Treat at night or late evening, when bees are in the tunnels, and leave the holes open for at least a day afterward so bees contact the insecticide.[1][5][4][2]
Carpenter bee or bumble bee?
Carpenter bees look like bumble bees but usually have a shiny, hairless abdomen; bumble bees have a hairy abdomen striped black and yellow.[2][4]
Bumble bees nest in existing cavities, often underground in old rodent burrows, while carpenter bees tunnel into wood.[2][3]
If you see several large bees hovering near the eaves or drilling into wood, Penn State says they are carpenter bees.[4]
Signs of carpenter bees
The entrance hole is perfectly round and about the width of your little finger, often with sawdust below; you may even hear buzzing or tunneling inside the wood.[2][5]
They prefer unpainted, weathered softwoods such as redwood, cedar, cypress and pine, in eaves, rafters, fascia boards, siding, shake roofs and decks.[2][1]
Damage builds when the same wood is attacked year after year, and the holes let in moisture, rot and decay. Stains below holes are another sign.[2][4][5]
Do carpenter bees sting?
Males hover in front of people near nests but can't sting; females can sting painfully but seldom do unless handled or bothered.[2][4][5]
For a sting, wash the site with soap and water, then apply ice wrapped in a cloth, 10 minutes on and 10 minutes off. An antihistamine or anti-itch cream may help; watch over the next few days for increasing redness, swelling or pain.[7][8]
Have someone stay with the person to watch for an allergic reaction. Call 911 for trouble breathing, wheezing, swelling of the face or mouth, or throat tightness, and use the person's epinephrine auto-injector if they carry one.[7][8]
Stopping carpenter bees
Paint bare wood, especially where bees have nested before; carpenter bees usually won't tunnel into painted wood, and stains are less reliable.[2][5]
Treat tunnels before they're finished: put an insecticide such as bifenthrin, cyfluthrin, deltamethrin or lambda-cyhalothrin into the opening, wait, then plug it with a glued dowel, putty or sealant.[2][5]
Sprays on wood surfaces deter some drilling but last only about 3 to 4 weeks (Clemson: less than 30 days), so they may need repeating.[2][5]
Penn State suggests dusting at night with a red-filtered flashlight to avoid stings, and wearing gloves, goggles and a dust mask because the dust often drifts; because of the risks of treating holes in eaves, it notes many homeowners hire a licensed pest control company.[4]
Traps, small wooden boxes with 1/2-inch holes over a hanging bottle, hung from eaves in early spring can reduce drilling.[2][5]
Keep garages and outbuildings closed while bees search for nest sites, which usually ends by late spring.[2]
Where sources disagree
When to plug treated holes: UC IPM says wait a day or two, Clemson 24 hours and Kentucky a few days; Penn State says not to plug immediately, re-treat in mid-summer and early fall, and fill the holes in fall.[1][5][2][4]
When to treat: UC IPM says early spring before nesting or fall after adults have emerged, since summer treatment of active nests does little; Penn State suggests spring, mid-summer and early fall.[1][4]
Tunnel length: UC IPM says 6 to 10 inches deep, Clemson about 4 to 6 inches; both say reused galleries can reach 10 feet.[1][5]
Generations: UC IPM and Kentucky describe one generation a year; the Forest Service says carpenter bees can live up to three years and have one or two generations a year.[1][2][6]
Common questions
- Do carpenter bees sting?
- Males can't sting; females rarely do unless handled.[1][2][4]
- How can I tell a carpenter bee from a bumble bee?
- Carpenter bees usually have a shiny, hairless abdomen; bumble bees have a hairy, black-and-yellow striped one.[2][4][3]
- Do carpenter bees damage houses?
- They can cause cosmetic and structural damage when the same wood is reused year after year, though they're seldom as destructive as termites.[2][4]
- What should I do if a carpenter bee stings me?
- Wash the area, use a wrapped ice pack 10 minutes on and 10 off, and watch for an allergic reaction; call 911 for trouble breathing or swelling of the face, mouth or throat.[7][8]
- Are carpenter bees beneficial?
- Yes. They pollinate crops and wild plants, including eggplant and tomato, so prevention with paint and plugged holes is preferred over insecticides.[6][1]
Sources
- University of California Statewide IPM Program, “Pest Notes: Carpenter Bees, Publication 7417 (June 2014).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pncarpenterbees.pdf (accessed 2026-11-11)
- University of Kentucky Entomology, “ENTFACT-611: Carpenter Bees.” entomology.mgcafe.uky.edu/ef611 (accessed 2026-11-11)
- Ohio State University Extension, “Bumble Bees and Solitary Bees & Wasps in Urban Landscapes, HYG-2143 (2011).” ohioline.osu.edu/factsheet/HYG-2143-10 (accessed 2026-11-11)
- Penn State Extension, “Carpenter Bees.” extension.psu.edu/carpenter-bees (accessed 2026-11-11)
- Clemson Cooperative Extension, Home & Garden Information Center, “Carpenter Bees (HGIC).” hgic.clemson.edu/factsheet/carpenter-bees/ (accessed 2026-11-11)
- USDA Forest Service, “Carpenter Bees (Xylocopa spp.), Pollinator of the Month.” www.fs.usda.gov/wildflowers/pollinators/pollinator-of-the-month/carpenter_bees.shtml (accessed 2026-11-11)
- MedlinePlus, U.S. National Library of Medicine, “Insect bites and stings (Medical Encyclopedia).” medlineplus.gov/ency/article/000033.htm (accessed 2026-11-11)
- Centers for Disease Control and Prevention, NIOSH, “Insects and Scorpions at Work.” www.cdc.gov/niosh/outdoor-workers/about/insects-and-scorpions.html (accessed 2026-11-11)
- iNaturalist, “Xylocopa virginica taxon page (order and family).” www.inaturalist.org/taxa/51110 (accessed 2026-11-11)