A carpenter bee hole is perfectly round, about half an inch across, roughly the width of your little finger, and drilled straight into bare or weathered timber before turning at a right angle. The bee is not eating the wood. She is excavating a nursery. Removal means treating the gallery, then plugging and finishing the timber, because an untreated hole gets reused and extended year after year.
If you have found a neat round hole in a fascia board, a patio beam, a pergola rafter or the underside of a deck rail, this is what you are dealing with and what to do about it.
What the damage actually is
The visible hole is the entrance. Behind it the bee turns and tunnels along the grain, creating a gallery that she partitions into cells. Each cell gets a ball of pollen and an egg, then a wall of chewed wood pulp.
A single season’s work by a single female is usually a few inches of tunnel and cosmetically minor. The problem is what happens over time. The same gallery gets reused and extended in later seasons, and a timber that offered one good site tends to accumulate several. Ten years of that in the same fascia run is a genuinely weakened board.
There is a secondary problem in Arizona that people underestimate. Woodpeckers hear the larvae and open the gallery to get at them, which turns a clean round hole into a torn strip of fascia. That is often the damage that finally prompts the call.
How to be sure it is carpenter bees
| What you see | Carpenter bee | Other causes |
|---|---|---|
| Hole shape | Almost perfectly round | Woodpecker holes are ragged and torn. Drywood termite kick-out holes are round but tiny |
| Hole size | About half an inch across, roughly the width of your little finger | Powderpost beetle holes are much smaller. Drywood termite kick-out holes are smaller again, closer to a pinhead |
| Location | Bare, weathered or unpainted timber, often the undersides | Drywood termites attack the same fascia, eaves and rafter tails, with no soil contact and no connection to the ground |
| Debris below | Coarse pale shavings of varying size, scattered loosely | Drywood termites push out hard six-sided pellets, all much the same size, which collect in a small neat heap |
| Staining | Yellowish streaking below the hole | Not typical of other wood pests |
| The insect | Large and robust. The boring female is glossy black with a smooth abdomen. The male is golden and furry with green eyes | Bumble bees are furry all over, including the abdomen |
Drywood termites are the pest most likely to be confused with carpenter bee damage in Arizona. They are well established here, they never contact soil, and they build no mud tubes, so the old advice about looking for mud from the ground does not help you. The tell is the debris. Irregular shavings mean a bee. Uniform six-sided pellets from a pinhead-sized hole mean drywood termites, and that is a different trade and a different treatment.
On the female, the shiny abdomen is the quickest field mark. Carpenter bees are frequently mistaken for bumble bees, and the difference is that a bumble bee’s abdomen is furry while a carpenter bee’s is smooth and glossy. The male looks quite different, and is covered below.
Why the males are the ones people notice
The male carpenter bee hovers near the nest site, faces down anything that approaches, and will fly directly at a person. It looks aggressive and is startling.
In the valley carpenter bee, the species most people meet in the Phoenix area, the two sexes look nothing alike. The male is golden and furry with green eyes, and he is the one in most photographs, including ours. The female that actually bores the timber is the large glossy black one.
He has no sting. Male bees of every species lack one, because the sting is a modified egg-laying structure.
The female can sting and very rarely does. She is inside the gallery most of the time and is not defending a colony, because carpenter bees are effectively solitary. Our separate guide on whether carpenter bees are dangerous goes into the sting question in more depth.
Why plugging the hole is not enough on its own
This is the most common thing homeowners get wrong.
Filling the entrance while the gallery is still occupied traps developing bees in the timber. They chew out, frequently alongside the plug, which leaves you with the original hole plus a new one.
The order that works is treat the gallery first, allow time for the treatment to take effect, then plug, then seal and finish the surface. Skipping the middle step is what produces the “I filled it and they came back” outcome.
Plug material matters too. Wood dowel and exterior filler both hold. Caulk alone is soft enough to be chewed straight back out.
What actually deters them
Carpenter bees strongly prefer bare, weathered, unfinished softwood. A painted or properly finished surface is markedly less attractive, and finishing the wood is the measure that holds up best over time on a Phoenix property. It follows the same principle as bee proofing the rest of the house, which is to remove what makes the structure attractive rather than react to each arrival.
Practical priorities, in order:
- Paint or seal exposed fascia, rafter tails, beam ends and the undersides of pergola timbers. Undersides matter most, because that is where they work.
- Repair and finish existing damage rather than leaving open galleries.
- Where a structural timber keeps being attacked, consider capping the exposed end with metal flashing.
- Do not rely on decoy blocks, ultrasonic devices or citrus sprays. There is no good evidence any of them relocate an established population.
What removal looks like on a service call
Carpenter bee work runs differently from a honey bee colony removal in Phoenix, because there is no comb to cut out and no wall cavity to open. The sequence is:
1. Identify every gallery, which usually means more than the one you noticed. 2. Treat each gallery at the entrance. 3. Return to plug and seal once the treatment has done its work. 4. Assess the surrounding timber for older, reused galleries that have been painted over and are still active underneath. 5. Talk through which surfaces need finishing, so the same run of fascia is not back next spring.
The last step is the part that actually matters. Treating the holes without addressing the bare timber that attracted them is a repeat visit waiting to happen.
Frequently asked questions
Do carpenter bees eat wood?
No. They excavate it to nest and discard the shavings. That is why you find coarse sawdust below the hole rather than the frass you would see with a wood-eating insect.
Will they cause structural damage?
A single season rarely does. Repeated reuse of the same timber over many years can, particularly in fascia, rafter tails and pergola members. Woodpecker damage following the larvae is often worse than the bees themselves.
Is it safe to seal the hole myself?
Sealing on its own usually does not work. If the gallery is still occupied, the developing bees chew their way out again, often right beside your plug, so you finish with two holes instead of one. Treat first, then plug, then finish the surface. On the sting question, the risk is low: the male that hovers at you cannot sting, and the female is inside the timber and very rarely does.
Are carpenter bees protected?
No. Carpenter bees are not protected under any Arizona or federal statute. They are, though, important native pollinators, which is a fair reason to limit treatment to timber that is actually being damaged rather than treating every bee on the property. Finishing the wood is the approach that solves the problem without reducing the local pollinator population.
Will painting really stop them?
It substantially reduces the attractiveness of a surface. It is not absolute, and a determined female will occasionally work painted wood, but bare weathered timber is chosen far more often.
The short version
Round holes about half an inch across, roughly the width of your little finger, in bare timber, with coarse sawdust below. The bee hovering in your face is the male, and he cannot sting at all. Treat the gallery, then plug it, then finish the surface. And pay attention to the undersides, because that is where they always start.
