I know it’s already been said in this thread, but I also love Permethrin. My son and I camp at a campground locally and a lot of spiders crawl up in between the tent and rain fly. You can see them there at night with a flashlight. Last year we started spraying Permethrin around the base of the tent on all sides. We have a rug outside each of our tents where you get in & out of the tents. In the mornings, you can see dead spiders on the rugs, the Permethrin on the tent kills them as they walk across it.

Permethrin is great stuff, well worth the $5.00 a can it cost. It brings sanity to an otherwise irritating mosquito filled night.