Carpenter Bees Attack!

Carpenter Bees Attack!

Carpenter bee closeup

As a kid, I recall spring and summer brought lots of bees. I specifically remember these huge bees and how they would bore holes into our wooden fences. They never seemed to do any harm to me so I left them alone. Now that as grownups we’ve moved from the city to the country and spring is upon us, I started noticing these huge bees here in Tennessee. There have been a lot of them around our house and barn (both structures have wood siding) but since the bees haven’t been bothering us, I didn’t pay much attention. That is until I noticed the number of holes they were drilling into our house and barn.

Carpenter Bee Damage

These holes are BIG (almost dime size) and there are a lot of them. But I really paid attention after doing some research on the Internet. The one or two-inch deep hole we’re seeing is only a tiny part of the tunnel they bore. That tunnel takes a 90-degree turn and can continue anywhere from 4 inches to 10 feet, depending on how many bees use it. Obviously this kind of tunneling can cause serious structural damage. So now we’re on the hunt to kill carpenter bees. Here are some interesting things we’ve learned:

  • Females drill the holes and are the only ones with stingers.
  • Males are very aggressive but do not have stingers so they can do little harm.
  • Adult carpenter bees “overwinter” (hibernate?) in these tunnels and then emerge in spring to mate and drill some more.
  • Insecticides can easily kill the bees but it’s difficult to eradicate the eggs those bees have already laid. Dusting with carbaryl (Sevin) seems to be most effective against infestation and re-infestation since applied dust can travel through the tunnels. This can kill the bees and help de-hydrate larvae the following season. Dusters are available at many hardware stores for around $15.
  • Some wait until fall to plug-up treated holes but holes should be plugged after the adult bees are dead.
  • Prevention includes diligent treatment of existing infestation as well as painting wood surfaces. Carpenter bees seem to prefer unpainted, untreated wood. Wood stain doesn’t seem to help, but pressure-treated wood does.

So now we’re spending an hour or two every week working on this carpenter bee problem. In our barn alone, which is a six-stall barn (pictures later), I must have dusted 50 holes so far. Uggg.

For more information, the following link was helpful to us and there are a lot of articles on Google:

Ohio State University Extension – Carpenter Bees, HYG-2074-94

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