They do too much damage to our house, tree house and swing set each year for me to be on good terms with them. I’ve read article after article that says they only go after non-treated, rotting wood, but that hasn’t been my experience at all.
See those holes? They were made by carpenter bees. That’s pressure treated lumber, and they started boring holes in it as soon as we finished building our tree house. They continue to bore new holes in it every spring.
When we built a new roof overhang over the basement a couple years ago, they bored holes through the new cedar supports, before we had a chance to finish them, and they continued to bore holes through them even after we stained them. They’re destructive creatures, I tell you.
So, several years back, my husband and I decided to build some carpenter bee traps to combat the problem. After a ton of research, we came up with our own design, and when we tested them, we couldn’t believe how well they worked.
Here’s a video of one of our carpenter bee traps in action.
Circular saw (or a hand saw)
1/2″ wood bit
7/8″ wood bit
1/2″ metal bit
4×4 post (A scrap of one is fine. You just need seven inches.)
(1)Mason jar (half pint or a regular mouth pint)
What You Do:
Step 1: Measure seven inches up from the end of your 4×4. Then, draw a 45-degree angle that radiates down from this point.
Step 2: Use a circular saw or a hand saw to cut the angle that you just marked.
This will leave you with a block of wood that is seven-inches tall in the back and four-inches tall in the front.
Step 3: Flip your 4×4 piece over, so that the flat bottom is facing up, and mark its center. Then, drill a 7/8-inch hole at the center point that is approximately 4-inches deep. Take care to keep your hole straight.
Step 4: Now, mark the location of your entry holes on the four sides of your block. Each hole should be two inches from the bottom and one and three-quarter inches from each side. Use your 1/2-inch wood bit to make your holes at an upward 45-degree angle. Continue drilling until your hole connects with the hole that you drilled from the bottom. Then, repeat with the remaining holes.
Here’s what your block should look like at this point.
Step 5: Unscrew the lid from your jar, and lay it on a piece of scrap lumber or a heavy metal plate. Find the center of your lid and mark it. Then, divide the distance between the center hole and the lip to find and mark the spots that you’ll use to screw the jar to the trap. Use a punch to make your holes.
Step 6: Use a 1/2-inch metal bit to make the center hole larger. Leave the other holes as is.
Step 7: Stick the lid back inside its ring, and screw the lid onto the bottom of your trap, taking care to make sure the 1/2-inch hole on your lid lines up with the 7/8-inch hole at the base of your trap.
Step 8: Add a screw eye to the top of your trap and hang.
How the Trap Works:
Carpenter bees discover one of the outer holes and crawl inside it to lay eggs. Once inside, the 45-degree tunnel casts their entry point in the shadows. They see light coming up from the hole at the base of the trap, and move towards it, assuming it’s the exit. Instead of finding their way out, they find themselves in the jar, and can’t figure out how to get back out. Victory!
We hang our traps where we’re seeing carpenter bee activity. Then, we treat the holes they’ve bored with Spectracide Termite Killing Foam (it’s formulated for carpenter bees, too). Afterwards, we fill the holes in with caulk or wooden dowels. If we’re short on time, we just cram a stick up the holes until we have time to make a more permanent fix. But it’s definitely important to block the holes right away because it forces the bees, who weren’t in their nests when you sprayed, to go in search of new nesting sites, and it also kills the larvae they’ve laid, so you don’t have more bees hatching out next year. Carpenter bees will build their nests in existing holes, if they can find them, so if you have a trap full of carpenter bee-sized holes hanging near by, they’re likely to crawl inside to check it out, and when they do, you’ll have them trapped.
Note: Spectracide now also sells Carpenter Bee and Ground Nesting Yellow Jacket Killer Foam. It has the same active ingredients as the termite foam, so use whichever one you’re able to find.