The grubs feed on grass roots, reducing the ability of the grass to take up water. When drought stress occurs, patches of grub-damaged grass turn brown and die.

Grub-damaged turf can easily be pulled up from the soil or rolled back like a carpet.

Skunks, raccoons, armadillos and birds may dig up the turf to eat the grubs. On warm-season grasses, damage is often seen when patches don’t green-up in the spring.

Other white grubs can damage turf grasses, but Japanese beetle grubs have a distinctive pattern of spines on the underside of the tail end.

In Alabama, newly hatched grubs are present during the last part of July and the first part of August in most years. They continue to feed on grass roots through the late summer and fall, overwinter in the soil as grubs, move up in the spring and feed a little at that time.

During dry periods, female beetles are attracted to watered lawns to lay eggs. Moist soil is needed for eggs to hatch and for newly hatched grubs to survive.

Two approaches are used in chemical control of white grubs: the preventive method and curative control. With the preventive approach, insecticide is applied before the grub problem develops.

Products containing either imidacloprid or halofenozide work well for preventive control. The granular formulations are applied with a lawn spreader. Optimal timing for preventive control is any time in June before egg hatch. Neither preventive insecticide is effective against large grubs once damage has occurred.