In an earlier post on possible June Bug damage, I showed some pictures from Racoon Valley Golf Course in Jefferson, Jay Goughner, owner and Supt. They showed what appeared to be June Bug damage in rough on a major part of the course. I stopped there last Friday and picked up some samples of the grubs for verification. This would be the first major June Bug damage that I have seen in my 31 years here and I wanted to be sure that was the problem. Below are pictures of the rough and a couple of insects in the soil.
Unlike the Chafer and Japanese Beetles, which do their damage in August to Oct., the June Bug does its damage in mid summer, July to early August.
The fairways in this picture were treated with imidacloprid (Merit) and the rough was not. It obviously worked on the fairway. If you have the problem now, you will have to treat with a Dylox or a similar compound and water it into the soil. That is very difficult to do.
The best way to identify the larvae is with the raster pattern. See the pictures below of a series of species.
I took the samples to Dr. Don Lewis in the entomology department on Monday. Here is what we saw under the microscope. These are June bugs (Phyllophaga spp)(also called May Beetle in some areas).
I have also had some other calls on suspected damage in Des Moines and other areas in central Iowa. If you have seen them, let me know.