I was in Norway and Switzerland last week for some professional meetings and was not able to post more information about the Japanese Beetles showing up in Central Iowa. During that time, I received several e-mails about beetles. They showed up in large numbers in the last week of June.
The first picture is from Nick May, Manager of TruGreen in Ankeny. It shows severe feeding damage on oak.
The second one from Dan Strey at the research station. We are seeing large numbers of adults this week.
The final picture is from a rose study next to the turf research area. I took this today, July 2.