On Thu, 28 Sep 2006 11:32:37 -0400, Stubby
wrote:

I have some crumbled spots in the concrete slab under my house. These
are at the edges where "tackless" strips used to be anchored. I'm
installing a floating floor now and want to patch the slab and prevent
insects from crawling in. Can anyone suggest a "permanent"
insecticide? In the old days we would have used chlordane but that has
been outlawed and is unavailable now.

If you're physically blocking the holes, why do you need insecticide?