I have a problem with carpenter bees in my basement year after year. I have vinyl siding over wood siding. Can’t locate where they are coming in. Could they be coming in under siding in holes in basement wall which is a stone wall? What would I look for outside to find them?
I tried Bee & Wasp spray along the perimeter of the ceiling around the top of the wall of basement. This only works for a short time. I kill about 50 bees per year. Can you help?
This is an easy one. If you read the answer I posted about carpenter bees going under vinyl siding, you’ll learn this is an all too common problem when wood siding is covered with vinyl siding. As the post explains, the bees will still be able to smell the decaying wood hiding underneath and gain access to it through small seams in the siding. Once under the siding, they’ll drill their holes and be successful at developing to mature adults.
Now the real problem is these nests won’t be easy to detect because the wood is covered. In most of these cases, you won’t see any of the typical signs because the bees are drilling under the wood. This means the sawdust won’t be seen and neither will the holes they create.
And as fall turns to winter, they’ll move into these holes and overwinter in a nest that is very well protected from the outside cold. This means they’ll be quite comfortable with a good chance of surviving and entering the home.
So come the new year and the spring when they become active, they’ll try to emerge to go foraging outside but because the siding is tight and tough to escape, many will end up moving to inside the home. So my best guess is the nests that are harboring hibernating adults and pupae are releasing them in the spring and that some of these are finding their way into your home.
The good news is the treatment to stop this is easy and highly effective. Basically you’ll need to dust along every row of the vinyl siding with Drione Dust.
This can be done with a Hand Duster and/or a Dustick depending on how easy it is to reach the siding. If you read up on Drione, you’ll learn it’s highly effective against carpenter bees and lasts a long time. So for you home I would recommend a thorough dusting in the spring and then another treatment with Drione in the fall.
If done right, you should expect immediate results. In other words, I expect you could knock out the existing nests immediately and the residual of the Drione would keep new nests from forming all summer.
And if you dust again in the fall, you should be protected throughout the entire winter so that any coming around to hibernate won’t be able to survive in the abandoned nests. This should keep them away from your home and out of your basement.
Lastly, even if you do a good job of dusting this spring, I strongly recommend you spend some time going around the outside of the home looking for any carpenter bees flying around soffits, overhangs, gutters, etc. Now if you find bees in any of these areas, I would expect these areas would be entry points. So to make sure they’re not using them as entry points, you’ll need to treat them with the Cypermethrin talked about in our article here:
No doubt vinyl siding can present a bit of a problem when treating for nesting bees but it’s nothing a good amount of Drione Dust can’t handle. And since this treatment will work on all pests, it’s a great way to stop anything that might want to nest under it. Get your siding treated as explained and I’m sure you’ll be able to knock out any carpenter bee nests present and keep new ones away all summer.