Carpenter Bees: Round Holes, Sawdust and Wood Damage in Texas

Neat, perfectly round holes about 1/2 inch across in fascia, eaves, decks or fence posts, often with a small pile of sawdust underneath, are the calling card of carpenter bees. The large bees hovering in your face are usually males, and males can't sting. The lasting fix is to deal with the active holes, plug them at the right time, and keep exposed wood painted.

Seeing fresh holes or sawdust? Call or text (210) 281-1064 or book online.

Reading the clues on your wood #

You often notice the damage before you get a good look at the bee. Signs to check:

• Round entrance holes about 1/2 inch wide. AgriLife's L-1826 fact sheet says no other insect cuts an opening that large and that round.
• Sawdust collecting on the ground, the porch rail or the siding below an active nest.
• Stains streaking down from the holes.
• Location: holes usually face well-lit spots with something overhead, such as the underside of an eave or a porch ceiling.

What does a carpenter bee look like? #

According to AgriLife, adults run 3/4 to 1 inch long and are usually shiny or metallic blue-black, often with a greenish or purplish sheen. Some males have yellow faces.

The surest way to separate them from bumble bees is the top of the abdomen. On a carpenter bee it is shiny and mostly bare; a bumble bee is hairy there. Carpenter bees also aren't social insects, so you won't find a shared colony the way you would with honey bees.

Which species? A University of Florida fact sheet hosted by Texas A&M lists Xylocopa micans ranging west to Texas and X. virginica ranging south to Texas.

What wood do they choose? #

AgriLife says carpenter bees favor softwoods such as redwood, cypress, cedar and pine, and will go after hardwood once weather or decay has softened it. TAIS points to weathered wood in particular: siding, fence posts, decks and eaves.

One spot is easy to miss when you paint. The UF sheet notes that the unpainted back side of eave trim is a frequent target.

Inside the tunnel #

Behind each entrance is a gallery. AgriLife and TAIS put the average length at 4 to 6 inches, sometimes up to 12, with 6 to 9 cells for young bees. Galleries are reused and extended year after year, and AgriLife says they can eventually stretch more than 3 yards. Development from egg to adult takes anywhere from 35 days to more than 3 months, according to the same bulletin.

Their calendar around San Antonio #

Adults spend the winter inside the tunnels. AgriLife says they usually come out in April and May; TAIS says early spring. Much of Texas sees two or more generations a year, and AgriLife notes that in warmer parts of south Texas, activity and breeding may carry on through the whole year. Don't assume winter means the holes are empty.

Do carpenter bees sting? #

The bees dive-bombing you near the deck are usually males, and AgriLife says males cannot sting. Penn State Extension makes the same point: the most defensive carpenter bees are the ones without a stinger.

Females can sting, but AgriLife says they do so only when handled or provoked. A nesting female can get aggressive if you disturb her, so take care when working near active holes.

How much damage can they do? #

The damage adds up as galleries are reused and lengthened. AgriLife lists weakened lumber, leaks in cisterns, holes and staining. The University of Kentucky adds that the openings let moisture in, which leads to rot and decay.

AgriLife also notes that inspections for carpenter bees sometimes turn up termites, carpenter ants or wood-boring beetles, so a close look at the wood is worth it.

Paint or stain? What the sources say #

If you'd like to keep some carpenter bees around, AgriLife suggests a block of softwood set out in the garden as a nesting spot away from the house.

A simple upkeep routine for your wood #

Carpenter bees reward neglected, bare wood, so most prevention is ordinary maintenance:

• Walk the outside a few times a year. Look along fascia boards, eaves, deck rails, pergolas and fence posts for fresh round holes or sawdust. In a warm south Texas year, there may be no truly quiet season.
• Paint what's bare. Include the back of eave trim and any board edges you can reach. Touch up latex paint before it peels.
• Build with the bees in mind. For a new deck or fence, AgriLife ranks pressure-treated wood alongside oil-based or polyurethane paint.
• Watch for soft or stained boards. Water getting in through old holes is what turns a cosmetic problem into rot.
• Leave the hole-plugging for after treatment. A plug over live bees just gets chewed through.

The right time to plug treated holes #

Never plug a hole that hasn't been treated. AgriLife warns that young adults inside will simply chew their way out.

After treatment, the sources disagree on the wait. AgriLife's L-1826 suggests a 12- to 24-hour wait, while Kentucky and UF recommend a few days. After that, the holes get plugged and badly damaged boards get replaced.

Signs it's time for a professional #

• Many holes in several places
• Nests high on a gable or over a second-story deck
• Boards that feel soft or weakened

AgriLife describes the professional approach as treating each hole individually, then plugging it and replacing damaged wood. It also notes that some of the products involved are generally sold only to licensed professionals.

How Pest Trappers handles carpenter bees #

A technician walks the house and outbuildings, marks the active holes, and checks how sound the wood is. Because Pest Trappers is also licensed for termite work, the technician can check for termite or carpenter ant damage near the bee holes at the same time.

You'll get a plain explanation of the options, including when the holes can be plugged and which repairs or paint will help keep the bees from coming back. Any product used follows its label; as AgriLife reminds readers, the user is always responsible for that. Pest Trappers LLC (TPCL #0887549) quotes after the inspection, so call for pricing. Town pages: Fair Oaks Ranch, Leon Springs and The Dominion, Comfort and Cibolo.

Frequently asked questions #