I discovered that the Japanese Beetle are attracted to Geraniums this year and die right on the plant - see my pictures below. I also go around and knock them into a soapy bucket and they die immediately.
My neighbor said she put down milky spores but it is very expensive and it does not last and if your neighbors do nothing to their yards like mine, and you have the plants they like: roses & hibiscus they will just come over to your yard anyhow. My hibiscus are slow to open this year so I have been finding Japanese beetles on my daylilies, coneflowers, and clematis. Don't put out the trap bags - they will just attract every beetle around and hardly any go into the bags - I know, I tried it.