I have a large area of grass in my back yard that has mysteriously turned brown and died. I also had a big problem with Japanese Beatles this year. So I'm assuming I have some kind of grub problem in my yard. How do I get rid of these things? I know there are grub control applications sold at places like Lowe's, but when is the right time of year to apply this kind of stuff to the lawn? I live in southern Michigan and our temps still remain in the 80's.