Spring has finally arrived! The flowers are blooming, the bees are buzzing, and the sun is out. But the buzz of bees isn’t always a good sound, especially when you start to see nickel-sized holes in your house or patio furniture.
These holes are likely caused by carpenter bees, appropriately named for their habit of drilling holes in wood. Mason and leafcutter bees lay their eggs in holes that are already there and don’t damage the buildings they live in. Carpenter bees, on the other hand, are wood-boring insects that can do some damage. Its important to note that carpenter bees do not eat wood like termites or carpenter ants. But when they drill holes for their nests, problems like water retention, decay, and rot can happen if nothing is done for a few years.
Carpenter bees have decided to live in your home. It may be tempting to use insecticides to get rid of them, but we strongly advise you to try less harmful methods first. Why? First, carpenter bees are incredibly effective buzz pollinators. Second, insecticide use for carpenter bees can also harm other local pollinators—like Mason and Leafcutter bees (among others)!.
Learn how pesticides can move from yard to yard in our The Importance of a Pesticide-Free Yard article.
A lot of our beekeepers have asked us what they can do to keep carpenter bees out of their homes, decks, and lawn furniture without hurting other pollinators that live there. Which we thought was a great (and timely) question to answer in this months bee blog post!.
Before we talk about how to safely keep carpenter bees from building nests where you don’t want them to, we want to make sure you know how to tell them apart from other buzzing insects in your garden and yard.
As spring arrives, you may notice neat round holes appearing in wood structures outside your home. Decks, eaves, fences – no wooden surface is safe! While your first instinct may be to blame bumble bees, the true culprits are carpenter bees.
These often misunderstood insects drill holes in wood to create nesting galleries for their young. But what motivates this unusual behavior? Read on to learn all about the carpenter bee’s wood-boring ways.
Carpenter Bees vs Bumble Bees: What’s the Difference?
First, let’s clear up some common confusion. Bumble bees and carpenter bees are entirely different species.
Bumble bees are furry, social insects that live in small colonies in existing cavities like abandoned rodent burrows. They do not damage structures.
Carpenter bees are sleek solitary bees that drill their own nest holes in wood. Their wood-boring habits can be destructive.
While both are large, robust bees, bumble bees have fuzzy abdomens with yellow and black banding Carpenter bees are mostly hairless and shiny black or metallic blue-black in color
So if you see new holes around your property, it’s carpenter bees, not bumble bees, doing the drilling.
Why Do Carpenter Bees Drill Into Wood?
Carpenter bees have specialized mouthparts well-adapted for chewing into wood. But what purpose does this serve?
They drill holes in wood to build nest galleries for egg-laying and larval development.
The holes provide a safe, weatherproof environment for carpenter bee offspring to grow.
Interestingly, bees don’t eat the wood they drill into. They discard the wood shavings after excavating. The holes themselves are the goal.
Carpenter Bee Nesting Habits
To better understand their wood-boring impulse, let’s take a closer look at carpenter bee nesting habits:
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Nest tunnels are perfectly round holes about 1/2 inch in diameter – just wide enough for a single bee.
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Older tunnels may be slightly oval from repeated use over multiple seasons.
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They drill into softer, untreated wood like pine, cedar, cypress, redwood and poplar. Painted or pressure-treated wood is less appealing.
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Holes can penetrate 6 inches deep into wood structures like eaves, siding, decks, outdoor furniture, fence posts, etc.
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Each tunnel has a single entrance hole that leads to one or more small chambers for larvae.
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Carpenter bees are solitary nesters. Each female carpenter bee prepares and provisions her own nest tunnel without cooperation from other bees.
Knowing when, where and how carpenter bees nest helps explain why they damage wood around homes. It’s simply their instinct to create the perfect nurseries for raising young!
Signs of Carpenter Bee Activity
Tunnels and holes are the most obvious signs, but look for these other clues that carpenter bees have moved into your neighborhood:
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Wood shavings and sawdust piles below holes from excavation work
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Large, shiny black or blue-black bees lingering around outdoor wood structures
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Perfectly round entry holes 1/2 inch in diameter in wooden surfaces
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Buzzing sounds coming from tunnels as females work inside
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Males territoriality patrolling entry holes to await emerging females
Catching carpenter bee infestations early allows you to take preventive measures before extensive damage or nest expansion occurs.
Why Drilling Damages Wood
While carpenter bees only drill holes about 1 inch deep, over time clustered tunnels can severely undermine the structure and appearance of wood.
Some reasons this boring behavior is problematic:
- Weakens wooden beams, posts, siding and furniture over time
- More prone to wood decay and moisture damage
- Makes wood more attractive to other pests like termites
- Ruins the aesthetics of wood with unsightly holes
- Can allow water intrusion into walls or roofs if holes penetrate exterior cladding
While carpenter bees rarely re-use old tunnels, other bees often do. This expands and compounds hole damage year after year.
Deterring Wood-Boring Carpenter Bees
Before resorting to pesticides, try these eco-friendly tips to discourage carpenter bees from damaging your wood structures:
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Apply a fresh coat of paint or sealer to exposed wood surfaces. Paint makes wood less inviting for nests.
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Install 1/4 inch metal mesh screen over vulnerable soffits, vents, etc. to physically block access.
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Plug old holes with caulk, wood putty or other sealants so they can’t be reused.
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Use a liquid repellent like almond oil, peppermint oil or tea tree oil on wood perimeters.
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Provide an attractive bee house to redirect nesting away from your home.
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Limit flowering plants near wood structures, as blooms attract foraging carpenter bees.
With persistence, you can get carpenter bees to nest elsewhere without harming these important pollinators. Understanding their wood-boring impulse is the first step to controlling damage.
A Fascinating Wood-Boring Species
While their habits may frustrate homeowners, carpenter bees are fascinating creatures perfectly adapted to their niche.
As solitary bees, each female works alone to build secure nests for her young in wood. She’ll diligently visit flowers to collect nectar and pollen to provision the nests as food for her larvae.
In fact, carpenter bees are efficient early season pollinators, often active before honey bees. Their place in nature is important, even if we don’t always appreciate their carpentry.
With preventive measures, carpenter bee damage can be minimized without destroying nests. A bit of patience, ingenuity and bee-friendly practices will have your property buzzing with life – not boring holes!
Identifying Carpenter Bees and Signs of an Infestation
Carpenter bees are the largest native bee species in the United States. They are usually all black or black and yellow, and you can see them hovering around the eaves of a house or the underside of a deck in the spring. The ones around my house regularly hit our windows every morning to let us know they are there.
People often mix up carpenter bees and bumble bees. To tell them apart, just look at their abdomens. Carpenter bees have shiny black abdomens, while bumble bees have hairy abdomens. Don’t be scared of them just because they’re big or seem mean! Males, who have white stripes on their faces, don’t have stingers, and females can sting, but they probably won’t unless you handle them or stick your fingers in their nests, which we don’t recommend.
Keep in mind that carpenter bees flying around your yard and house doesn’t always mean they’re drilling holes in your house. A few things to look (and listen) for:
- Deep, nickel-sized holes perfectly drilled into wood;
- Wood shavings or sawdust in and around the hole;
- Carpenter bee poop may show up on the wood below the hole as a yellowish-brown stain.
- If you pay close attention, you might hear the sound of wood being chewed.
- Often, the males will wait outside the nesting hole while the female works inside.
Why Carpenter Bees Drill Holes in Houses: A Moment of Science
FAQ
What’s the difference between a carpenter bee and a bumble bee?
Why do bees drill into wood?
Should I fill carpenter bee holes?
Do Wood Bees drill holes in wood?
But here’s the thing: The name “wood bees” is a colloquial term for carpenter bees, a type of bee known for drilling holes in wood. They drill into wood to create their nests. This means that wood bees (carpenter bees) can drill holes into wooden areas around your home, such as inside roof eaves or wooden siding.
How do carpenter bees drill holes?
Carpenter bees use their powerful mandibles to drill holes in circular motions in wood. This results in a network of internal tunnels and chambers. Why Do Carpenter Bees Drill Holes? Unlike honeybees, carpenter bees are solitary creatures that typically exist together in very small groups.
How do you keep carpenter bees from burrowing in wood?
So can filling in any holes with dowels or wood putty to keep bees from burrowing. And as already mentioned, citrus and other essential oils like lavender and citronella do a good job of offending carpenter bees. Carpenter bees often bore holes in wood during the spring to lay their eggs.
Are carpenter bees (wood boring bees) dangerous?
Carpenter bees, also known as wood boring bees because of their diet and choice of habitat, are large black bees that look very similar to bumble bees. Yes, they are notorious for drilling holes in wooden furniture and damaging it.
Is wood damage caused by bees in your furniture?
Yes, wood boring bees, also known as carpenter bees, are notorious for drilling holes in wooden furniture and damaging it (18 Ways to Get Rid of Carpenter Bees (Wood Bees) Without Killing Them). The warm sunshine and flowers blooming may bring a pleasant buzz from bees outside, but their buzzing inside your house is not a welcome sound.
How deep do Wood Bees drill holes?
Wood bees only drill holes one to two inches deep, which isn’t deep enough to cause significant damage. With that said, multiple holes can make your home look unsightly. That’s why it’s wise to use citrus or almond oil on areas of exposed wood. Spray one of these oils in the early spring before the wood bees emerge and nest.