I sometimes have a ton of cockroaches outside, none inside, and rarely one in the garage. I've been using the bait gel, which works good but I'm wondering if there is something better? Once the gel is dry it seems to stop working. Is Bifen I/T a good choice for open areas of the yard that will also be getting rain soon? Even though a large portion of the yard is a lawn, I really only see them on concrete areas or dirt.