Larvae from European Chafer and Japanese Beetle can be a problem in turf in Michigan. As with any pest scouting, it is an important step in determining the true cause of a problem. A healthy lawn can support a grub population of five or more grubs per square foot with no visible damage. That would be 50+ grubs per roll of sod. A high grub population can cause primary damage to turf by feeding on roots, and also secondary damage from animals digging and feeding on the grubs.
Grub control products are either preventative or curative, and depending on what type, only work at certain times of year on certain life stages. Looking at products in the store can be confusing, so Michigan State University Extension has a list of available products, and outlines why and when they work. Read the article here.