For the most part, white grubs are the most common issue in northern Indiana yards, although there are others. Grubs are from the Japanese beetle that lays eggs in softer soils. Once grubs are present they will eat the turf roots in the fall preparing to overwinter, and this may kill large areas of turf which can then be picked up and moved in chunks, resulting in a lawn that appears to be going through road construction. The damage is severe, and can only be repaired by reseeding or laying sod the next season.

Certified applicators can apply Dylox to immediately knock out the grubs after damage has taken place. Once grubs have occurred, beetles have radar and can return to the exact same place meaning a preventative has to put in place.

Purdue offers the following free download about Japanese Beetles:
https://extension.entm.purdue.edu/publications/E-75.pdf