You could go my route with weevils and collect them in a bottle with soapy water? There are "board traps" were you lay a board or something down for them to hide under then some time later (a day or 2?) pick up the board and grab them? There is a product called tanglefoot, I'm unsure if that works for potato bugs but I imagine it would? I used it like a caulk gun to seal the two boards of my raised bed. :)

Spinosad.