This is a work in progress and I up date it when I can, usually in the winter. This is a minor disease and there are no controls. I can always predict their emergence here in Michigan. They seem to appear just before raspberry harvest. There are no good organic controls.
Traps are effective but have the disadvantage of attracting the beetle from long distances.
When using Japanese beetle traps be sure to set the traps outside the planting. I would set the traps 100 to 150 ft away and empty to contents daily. Insecticides will kill the beetle if used at high enough rates but new beetles will quickly move into the planting to take their place. Applications of insecticides to control the grubs which feed mainly on grass roots seem to be the most effective way to keep this beetle down. Wilting of the shoot tips in the summer are a sign that this pest is out.