Damage from grub feeding can range from mild to severe and first appears as brown patches of dead grass, usually in sunny or exposed locations. If feeding is heavy, the roots are almost completely severed and the sod can be rolled up like a carpet. Grubs are also a tasty treat for birds and rodents, and to get to the grubs beneath the soil they have to dig. So holes and scars in your lawn can also be an indirect consequence of grub infestation as animals dig around for a meal.