There are a few indications that you can look for in your yard to determine if you have a grub problem. First is looking for brown dead patches on the lawn and where the grass will pull up easily because it doesn't have any roots, grubs feed on grass roots.Next, you’ll find skunks or raccoons feeding on your lawn, they dig holes in the lawn because they can smell grubs and they want to eat them. These animals can cause more damage to the lawn than the grub can, even crows like them and can leave holes all over your lawn trying to eat them. It will be a matter of time before your lawn is overrun with weeds as parts of your lawn die and grass will no longer grow there.