Carpenter Bees are a destructive bee that creates tunnels in desirable wood on and near homes. They bore a hole nearly a 1/2 inch in diameter (see Image 1) then a tunnel 8 to 10 inches long, down the length of the board. This can weaken the structural integrity of the wood, causing the homeowner to have to repair or replace damaged wood.
There are a number of species of Carpenter Bees found throughout the United States. The most common one in many areas is the large bee that looks like a bumble bee (Image 2). A true Bumble Bee (Image 3) has a hairy abdomen, compared to no hair on a CB.
Male Carpenter Bees (Image 4) have no stingers while only females (Image 5) can sting.
The young adults over-winter in the tunnels, then they mate and clean out and enlarge old tunnels or create new ones. Then they create a mixture of pollen and regurgitated nectar that is placed at the end of the tunnel. One egg is placed on this “food” and the chamber is sealed off ( see Image 6). In the fall the young adults emerge and feed on nectar, then return to the tunnels to over-winter.
Carpenter Bees prefer to borer into bare, weathered and unpainted wood. The best way to deter Carpenter Bees is to paint exposed wood surfaces. It is recommended to use paint, not stain or water-proofer.
The most effective control for Carpenter Bees is to use a chemical dust and a puffer and apply it into the holes. Hi-Yield® Multi-Use Dust is a Deltamethrin dust on a talc-like carrier which is nearly water-proof so can not be washed off, making it the longest lasting dust available. Apply in the very early morning or late evening, in spring or fall when they are coming and going into the holes. The Carpenter Bee doesn’t need to be in the hole when you apply, if they enter the hole after application and get into the product they will ingest it when they clean themselves and die later. If you are afraid to get near the holes, an application of ferti•lome® Wasp & Hornet Killer may be used. This product will spray up to 20 feet– no climbing necessary. If the area is very large, Bifenthrin has been shown to be very effective on Carpenter Bees. Mix Hi-Yield® Bug Blaster at the labeled rate and spray, repeating again in 2 weeks. Repair the holes with putty or caulk.