We had a bad run on them things the beginning of every summer. They were stripping our fruit trees bare. We tried traps, but it seemed that only attracted more of them even though we put the traps as far away from the trees as we could. So know I just go out and spray the trees with Diaz-anon... So far so good. It was crazy the first few years we planted new trees. With in a few days we had stalks left.
I did hear about the milky-spoors stuff, but just have not tried that yet....But will.
Milky spore is the only long term control. USDA went to Japan to figure out why they weren't a problem there, and found it was because of the spore. (MS is a bacteria that attacks the grubs in the ground, spreading more spores) It does take a few years for control, and it is far more effective if your neighbors put it out as well.