June beetle grubs damage turf by eating grass roots. Moles digging into lawns or flocks of birds feeding on lawns sometimes indicate the presence of grubs. Most lawn grasses are subject to attack. Damaged patches of grass feel loose and sometimes can be rolled up like a carpet. But, when the grass is growing rapidly in the summer and is not suffering from drought, infested areas may remain green on top even though the roots are eaten away. These areas won’t "green up" the following spring. Damage from cold, drought, nematodes, or maintenance practices may resemble grub damage so, use a knife or spade to cut several 1-foot square samples, 3 inches deep, from the edge of the damaged areas. Fold the sample back and examine the soil for grubs. To differentiate them from other grubs, June beetle grubs crawl on their backs with their legs up. They can also be identified by the pattern of spines (rasters) on the rear ends. Treatment is often required when an average of three to five grubs is found per square foot.