s12, I've never had that problem, but I imagine something like Raid bug spray would kill them. Raid now even makes an all natrural spray or two, which I've tried, and seems to work on ants and stuff. I don't know about keeping them from coming back though. I would probably try some neem oil spray or something similar.

Hey, wait a minute. White stains? So maybe that's what those were on my outdoor grow. I never worried too much about bug damage on my outdoor grow. Hey, it's going to happen, and you'll still get weed.