The number one question that I have received over the last two weeks is “How do I manage the carpenter bees making all of the holes in the wood?”. These are pollinators. So, I usually recommend to discourage the bees and not kill them. Wood that is painted or coated with an oil stain can help, but not always. I prefer using a pyrethroid like permethrin to spray on the wood. As with most insects, they really dislike this and move on and, unfortunately, some may die if they get a big enough dose. Permethrin is found in many insect sprays, especially those made for horse stables and can be found at garden centers and farm stores. You will have to reapply every 10 days until nesting is done and everywhere that you don’t want the bees. You will also have to plug the holes as they will overwinter there in the fall. There are other recommended insecticides. If you would like a list please let us know. Here is a link to our fact sheet on Carpenter Bee management. http://ohioline.osu.edu/hyg-fact/2000/2074.html
I thought that I would include a few pictures to help tell the difference between carpenter bees and bumble bees. The carpenter bee on the left has a smooth, black rear end and the bumble bee on the right has a fuzzy, yellow-stripped or black rear end.