If you can't build one of these yourself, here is an affiliate link to purchase one on Amazon with a very similar design: https://amzn.to/3aw2ek6

To prevent Carpenter Bees from digging holes in my new screened in porch made primarily of cedar, I found a few references and videos online to this type of trap, so I'm not claiming to have come up with this on my own. The concept is simple, they buzz around looking for a spot to drill a hole and will prefer to have a hole already started to save them some chewing time. We can trick them into crawling in the hole in this box, where they follow the light down to the bottle and into the jar. They can't get back out because their flapping wings won't fit back through the opening, and it's too slippery to grip anything.

The key to the trap is that the hole needs to be under an overhang, up at a slight angle, and have a diameter between 3/8" and ½". I made one that's half an inch for the fat ones. I used a pickle jar because the lid was large enough to cut the hole for the pop bottle top and still have diameter for a couple small screws to hold it in place. They prefer corners and overhangs, so place it accordingly around your deck or wooden overhangs.

The one mistake I made in this design (which was totally off the top of my head using available scrap) is that I didn't slope the roof to allow rainwater runoff. The jar collected a little water the first time it rained, so I just caulked the joints around the roof.