Those pests are a bitch. Mostly because you may control them in your yard but they are everywhere and the adults can fly long distances. I use very few pesticides but on a lawn I would use something long lasting like Scott's Grub-X along with predatory nematodes. For your flowers use BTg and apply weekly during the season. There are some predatory wasps but it will take several years of releasing them to have an effect.
Don't grow white roses they are like a magnet to them. Tall Fescue is the most resistant grass.
You could always eat them!