Interesting article. I will have to do that in my workshop. It has open spots that they get into and build nests in there too. The porch is just a concrete slab that has a big crack in it. They are going in the crack and building under the concrete. I am going to try spraying the rest of the can in there and filling it with concrete from a bag. Then I will add some water to basically dry set the whole mess. Kind of a wasp tomb if you will.
I thought about silicone but not knowing how big it gets could be a lot of silicone.
I thought about silicone but not knowing how big it gets could be a lot of silicone.