Quick answer
Grubs are beetle larvae that feed on grass roots. The clearest sign is brown turf that lifts up like a loose rug. Check the soil before treating, because a small number of grubs usually isn't a problem.
Signs of Grubs
- Irregular brown patches that don't green up with watering
- Turf that peels back easily with no roots attached
- Animals such as skunks or birds digging in the lawn
- Spongy feel when you walk across the area
How to Check
Cut a square of turf about one foot across on three sides and fold it back. Count the C-shaped white larvae in the top couple of inches of soil. A handful per square foot is often tolerable; heavy numbers point to the cause of the damage.
After Grub Damage
Once the problem is handled, damaged areas can be repaired with sod or by letting Bermuda spread back in during the growing season.