I couldn't really see the leaf hoppers doing much, they hang out on the stems, mostly. Caterpillars were causing some pretty bad damage on my young plants. I sprayed them with BT the other day, haven't seen any since.Meh. Watch the plants, not the bugs. There are always going to a few. Take gentle measures if you like, but I probably wouldn't do anything much unless the plants appeared to be suffering. If everything's still green and growing, maybe wait a while, see if the predators come around. It's early in the season yet.