The adults emerge from the pupal cases a few weeks later but remain in the soil until spring. Thus, eggs are laid every third year, and the severe damage caused by their offspring usually occurs only every third year. Two species complete development and change to the adult stage in one year. These species attack roots of certain grasses and may become abundant enough to cause severe damage. The most severe damage usually occurs between the time of planting and runner development.
Damage is most likely to occur when strawberries are planted on newly plowed sod.
The grubs feed on the roots of strawberry plants and either kill or severely weaken them. Avoid planting strawberries on newly plowed grassland. The danger of insect damage can be reduced by rotating crops and cleanly cultivating the crop that precedes strawberries.