How and when to treat Japanese Beetles and Grubs

The immature stage of the Japaneses beetle - the white grub - typically has a three year life cycle. However, most of the damage to ornamentals and turf grass happens during the spring and fall the second year, when grubs are present in the top inch of the root zone, heavily feeding on grass roots and thatch. In the third year of the cycle, the grubs rise out of the soil as Japanese beetles. These beetles feed on surrounding plants and lay eggs in the soil throughout the summer. These eggs eventually hatch into grubs and the cycle beings again.