I went our on my back patio about a month ago to turn off my water...and found about 7 widows on my furniture. I thought they were black widows, but some of the egg sacks looked like the brown variety. Anyway, bought some Demon WP packets and haven't seen them since. Did a quick google and came up with this site...not the one I bought it from...but it's the stuff that did the job.
Demon Insecticide - Demon WP - Demon Max