Pests and Diseases: Carpenter Bees

In today’s post, I thought we would look at carpenter bees. While they resemble bumble bees, they are definitely different. If you’re into getting up close and personal, you’ll notice that the abdomen of carpenter bees is black and shiny whereas the abdomen of bumble bees is hairy and has yellow stripes. If you don’t want to get too close, just notice their habits. Carpenter bees are most often spotted hanging around eaves and other wooden surfaces in the spring or early summer. This year, the carpenter bees have been quite active already.

This time of year is when you will see the bees flying in great numbers and hovering around wooden structures…what you are witnessing is actually the courting ritual. The males are trying to impress the females, and while the males will often hover at the tip of your nose, there’s no reason to be frightened; the males don’t even have a stinger.

carpenter bees

Photo courtesy of www.carpenterbees.net

The female will excavate holes that are about the diameter of your finger into the wood so that she can lay her eggs. Her eggs will develop in the nesting holes and will emerge in late summer as adults. When it’s time for winter to roll around, the adults will go back to the nesting holes to overwinter. The damage that carpenter bees can inflict on a wooden structure can be quite impressive. There are several theories on the best method for controlling them…here are a few:

  1. Paint or stain the wood. Carpenter bees prefer wood that is untreated for their nesting holes. It is generally believed that painted wood seems to deter them more than staining does.
  2. Fill the holes. To me, this is like playing the whack-a-mole game at Chuck E. Cheese. You fill in one hole so the bee just moves over a bit and lays more eggs in a different location.
  3. Use insecticide. I am totally against this. Period.
  4. Alternative nesting areas. If carpenter bees are particularly worrisome around your home, consider providing wood that they can use as nesting areas. Sure, you can’t put up a vacancy sign at the desired location but you can provide them shelter. After all, they pollinate fruits and veggies too, ya know.

 

I should also note that while carpenter bees lay their eggs in wood, bumble bees form nests in the ground. That should help you ID them better as well. If you have experience with carpenter bees and would like to recommend any other treatments, please leave a comment below or e-mail me. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list (upper right hand corner of this page), become a fan on Facebook and follow me at Twitter. Happy gardening!

April 3, 2012Permalink 2 Comments

2 thoughts on “Pests and Diseases: Carpenter Bees

  1. The carpenter bees nesting in my wooden wisteria arbor have recently been falling to the ground and slowly dying. They appear to be adults, and I wondered if they suffer from mite infestation as do the honey bees. One of them had a small white slug attached to its abdomen! Could slugs be climbing the arbor and entering their holes? It must have been a female, as when I tried to remove the slug, it stung me! Thanks for any insight here. While I wonder if their nests weaken the arbor and shorten its life, they are such great pollinators, I don’t mind them.

    • Thanks for not killing them Jenny! They really are beneficial as pollinators. I’m wondering if the slugs are actually the larvae of the carpenter bees. The larvae should have emerged by now but they could be behind schedule. Since I’m not an entomologist, I recommend taking a dead bee and a slug to your local Extension office and having them take a look. Please post the results here…I’m intrigued!

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