What is drilling perfectly round holes in my deck?

A clean, round hole about half an inch across in bare or weathered wood is a carpenter bee gallery entrance. The hole goes straight in about an inch, then turns and runs with the grain. Sawdust below the hole and yellow staining on the wood underneath are the other two giveaways.

Do carpenter bees sting?

The males, which are the ones that hover aggressively in your face, have no stinger at all and cannot sting. The females can sting but are docile and essentially never do unless handled. The alarming behavior and the actual risk are almost exactly reversed.

Are carpenter bees the same as bumble bees?

No, though they are close in size and often confused. A carpenter bee has a shiny, hairless, almost polished black abdomen. A bumble bee's abdomen is fuzzy and usually banded yellow. Bumble bees nest in the ground and are important pollinators we do not treat.

Does painting wood stop carpenter bees?

Paint helps considerably, and a well-maintained painted surface is much less attractive than bare or stained wood. Stain and clear sealer help far less. It is not absolute protection, but on structures we treat, painting afterward is the single most effective thing a homeowner can do to keep them from coming back.

Carpenter Bees Drilling Your Deck?

First: The One Hovering at You Can't Sting.

That's worth saying immediately, because it's the reason most people call. The bee that plants itself in front of your face, follows you down the deck steps, and dive-bombs you is the male, and male carpenter bees have no stinger. None. It's pure bluff — he's defending a patch of airspace and he will do it to you, your dog, a passing robin, and a thrown tennis ball with equal conviction.

The females do have stingers, and they're the ones actually boring the wood, but they're docile and essentially never sting unless you grab one. So the scary one is harmless and the destructive one leaves you alone.

How to Know It's Carpenter Bees

Three signs, and you usually have all three:

The hole. Startlingly round and clean, about a half-inch across, like someone went at your deck rail with a spade bit. It goes straight in roughly an inch, then makes a sharp turn and runs several inches along the grain.
The sawdust. A small cone of coarse, pale shavings on the ground or the deck board directly below the hole.
The staining. Yellowish-brown streaking on the wood below the entrance. That's waste, and it's what tells you the gallery is active rather than left over from a previous year.

The bee itself is big — bumble-bee big — but the abdomen is shiny, black, and hairless, almost like polished plastic. That's the single most reliable tell.

Carpenter Bee — treat it

Look for: Shiny bald black abdomen. Hovers and holds station in one spot. Round holes in bare, weathered, or stained wood — decks, rails, fascia, soffits, pergolas, sheds, fence tops, playsets.

What it does: Bores a gallery to lay eggs. One year's damage is cosmetic. Ten years of the same galleries being extended and reused is structural.

Bumble Bee — leave it

Look for: Fuzzy abdomen with yellow banding. Nests in the ground, in old rodent burrows, under sheds, in compost. Doesn't bore wood at all.

What it does: Pollinates, in decline, and dies off naturally each fall. We won't treat these. If one is nesting somewhere genuinely awkward we'll talk about relocation instead.

Honey Bee — live removal

Look for: Smaller, amber-brown, fuzzy, often carrying visible pollen. If they're going into a wall or soffit in numbers, that's a colony, not carpenter bees.

What it does: Gets removed alive and relocated. We run our own hives, so live removal is always what we try first — where a colony can be reached safely and the removal is cost-effective, the bees leave alive.

Woodpecker damage — the sequel

Look for: Ragged, torn-open channels rather than clean round holes, often following a line along the grain.

What it does: That's a woodpecker excavating carpenter bee larvae out of existing galleries. It's a sign you had an untreated infestation, and it does far more visible damage than the bees did.

Why It's Worth Dealing With

A single season of carpenter bee activity is genuinely minor — a few holes in a rail. The problem is that it doesn't stay a single season. Females return to existing galleries and extend them, and their offspring emerge and start again in the same wood. After several years of that you can have a foot or more of tunneling inside a single fascia board or deck rail, and it's hollow in exactly the places you'd rather it weren't.

Then the woodpeckers find it. Around Harrisburg that's usually the point at which people call us — not because of the bees, but because something has torn a long ragged gash down their cedar fascia going after the larvae. That damage is worse than anything the bees would have done and it's entirely preventable.

How We Treat Them

Carpenter bees are one of the few jobs where the treatment has to go into the gallery rather than onto the surface. Spraying the outside of a deck rail accomplishes nothing — the female is a foot inside the wood. We dust each active gallery directly at the entrance and leave the holes open. That's deliberate, not an oversight — returning females keep walking through the dust and carrying it down the tunnel, which is what reaches the brood. Plugging a gallery with a live bee in it just gets a new exit hole chewed an inch away.

The holes do need filling — but later, and not by us. A gallery bored into wood doesn't close on its own the way a cicada killer's burrow in soil collapses, and an open gallery is an invitation to next year's females. Once we've told you the gallery is finished, fill it with wood putty or caulk and paint over it. That's straightforward homeowner or handyman work, and doing it at the wrong time — while a bee is still in there — just gets a new exit chewed an inch away.

Timing on the treatment itself matters more than any of this: spring, as the overwintered adults become active, is when it does the most good for the least work.

Estimates are free and depend on how many galleries there are and how much of the structure is involved. Text a photo of the worst section to 717-379-3248 and we can usually scope it without a visit.

What Actually Prevents Them

Paint, not stain. Carpenter bees strongly prefer bare, weathered, or stained softwood. A well-maintained painted surface is markedly less attractive. Clear sealer and semi-transparent stain do very little.
Fill old holes once they're inactive. An open gallery is an invitation — it saves the next female most of the work.
Watch the usual suspects. South and west-facing fascia, deck rails, pergola beams, shed trim, fence tops, and the underside of anything horizontal and unpainted.
Don't bother with the traps beyond the novelty. They catch some bees. They do not resolve an established gallery system.

Where We Cover

All of the City of Harrisburg (17101–17104, 17109, 17110) plus Penbrook, Paxtang, Steelton, Highspire, Colonial Park, Lower Paxton, Susquehanna Township, and Linglestown. Also Hershey, Hummelstown, Mechanicsburg, Camp Hill, Palmyra, Middletown, Carlisle, and Lebanon.

Frequently Asked Questions

That bee keeps flying at my face. Should I be worried?

No. That's the male, and males have no stinger — it's physically impossible for him to sting you. He's defending territory and the display is entirely bluff. He'll do exactly the same thing to a bird or a leaf blowing past. The females, which can sting, are the quiet ones going in and out of the holes, and they essentially never do.

You're beekeepers. Why are you killing bees?

Fair question, and we get it a lot. Carpenter bees are native solitary bees and genuinely useful pollinators — we're not out to eliminate them from Central PA and we won't treat them where they're boring into a dead tree or a fence post nobody cares about. What we treat is structural damage to a house or deck. If they're in a spot that doesn't matter, we'll tell you to leave them. That's the same call we make on mining bees and bumble bees.

Can I just plug the holes?

Not while they're active, and we don't plug them as part of the treatment — a female sealed inside simply chews a new exit an inch away, and we want the holes open so returning bees keep contacting the dust. But they do need filling eventually. Wood doesn't close over the way soil does, so an abandoned gallery stays open and gets reused. Once we've told you it's finished, wood putty or caulk and a coat of paint is the fix, and it makes that spot much less appealing next spring.

When is the best time to treat?

Spring, as overwintered adults become active and before the new generation is sealed in. That's when treatment does the most with the least. Late-season treatment still works but you're dealing with more galleries and more established damage, and the sealing has to wait.

Something tore a long gash in my fascia board. Is that the bees?

That's a woodpecker working an existing carpenter bee gallery to get at the larvae. It means the infestation has been there a while. We treat the galleries so the food source is gone; the fascia repair itself is a carpentry job, not a pest one, and we'll say so rather than pretend otherwise.

What else do you handle?

If it's a hole in the lawn instead of the wood, see ground bees. If something's chewing structural wood indoors, see carpenter ants. Otherwise: stinging insects, pest control in Harrisburg, or our pollinator-friendly programs. There's a longer read on carpenter bees in cedar fascia.

Big Black Bees Drilling Holes in Your Deck?