I get tons of them. They absolutely love rose and peony blooms. Then they go after my apples and chestnuts. I think they have a fairly short lifespan so a couple of sprays two weeks apart should take care of them.
They could be the evil twin of the jap beetle. sounds like they have almost exactly the same life. Eat leaves breed and lay eggs for next year. only difference is they hatch about a month or so earlier.