They sell Japanese beetle traps. There is a chemical element, but it is just a pheromone to attract them, then they get trapped in the bottom of the bag and die. We use them and they are quite effective. Bug-B-Gone are the one's we use.
She can contact the UW extension office as they have a publication or download it from the uwex.edu website. Its under Cooperative Extension garden publications. The optimum treatment time is a month away. There are no good biological controls for this pest as it eats anything!! If you need help locating the document let me know!!