by Millie Davenport, Horticulture Extension Agent, Home & Garden Information Center, Clemson University, 2009
Hi, I am Millie Davenport, a horticulture Extension agent with the Clemson University Home & Garden Information Center. Today we’ll talk about carpenter bees.
Today we are in the South Carolina Botanical Garden and we are going to look at carpenter bee damage. That is one thing that you are often going to see in your landscape whether it be on your siding, or fences, trellises, anything made of wood in your landscape you are likely to see carpenter bees coming in to invade in April and May.
Carpenter bees look very similar to bumble bees. With your bumble bees, they have more yellow on their abdomen. Now, however, the carpenter bee, one way you’re definitely going to know it is a carpenter bee is that it has a very dark, shiny, black abdomen on the back section. The male, however, has a white head, so you can definitely tell which is male and which is female.
The good news is that carpenter bees are not very aggressive. The male doesn’t even have a stinger. He is very territorial however and he may even come up and buzz you. But you will definitely see the white on his face and you will know it’s a male and not to fear. The female however, she does have a stinger, but since they are solitary insects, they are not social like honey bees. They have no reason to really defend themselves and sting you unless you really mess with them a lot. So, that’s the good news.
However, the bad news is that they do cause a considerable amount of damage to wood. The female will actually create holes in the wood that are about a half an inch in diameter. And, she’ll go in and use that as a nest for laying her eggs. Once she gets in there you can see that she will go in and she’ll make a sharp 90 degree turn into the wood to create her gallery. And that is where she will actually bring in nectar and pollen for food for the eggs.
So, if you have wood siding on your house, fence, deck, that type of thing, you’re going to get a lot of damage. Because what happens is with each season, if you don’t close these holes, the new females will reuse them. And often times they won’t just go in and reuse the gallery as it is. She will actually extend that gallery out in more length in your wood structure, so years and years of use will actually cause a lot of damage.
First, to prevent the damage, you will want to use some type of synthetic pyrethroid, you can spray that on the structure. There are many of them out there, available that are labeled for carpenter bees. You can spray that as a preventative on the wood to prevent them from boring into that wood.
Now, if you already have damage, you are still going to want to do something about it. Once you do see the holes there and you see that you have activity in April and May, you are going to want to wait until the end of the day, more toward night, dusk. Get yourself an aerosol bee and wasp spray that is like a knock down insecticide. You will want to spray that into the hole at dusk when they are likely to be in there. You will wait 24 hours after you’ve sprayed that, and once you’ve done that, you can actually go in and plug the hole with a wooden dowel. Put the wooden dowel down in there and cover it up with wood putty. Now, some people wonder why wouldn’t you just put the wood dowel and putty down in there without using the insecticide. If you choose to do that, the female that is in there can actually bore back out, so you are defeating the whole purpose of trying to get rid of her.
So, if you have wood structures in your landscape that are not protected with an oil based paint or polyurethane, you’re definitely going to want to be on the look-out come spring for any of these carpenter bees in your area, that way you can help control them and prevent them from invading any of your structures.
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