I don't know anything about beetle traps but I know that I personally wouldn't use sevin. Then again, I am trying to do everything as chemical-free as possible. I would recommend planting a sacrificial crop, like yellow yarrow, nearby, so the beetles go for that over your trees or whatever they are on. And if you have the free time, or pent up aggression, you can always go out to the yarrow and pluck off the bugs and squish 'em! (or drop in small bucket of soapy water)