Small grubs begin feeding on grass roots, consuming more over larger areas as they grow. Most damage occurs in late summer and early fall after grubs are half grown. Grubs move deeper into the soil to over-winter and as the soil warms in the spring, they move up to the grass roots, feed a short time, pupate, and then emerge as adults to begin the cycle over again. Adults are active in the spring from late May until early July. Eggs are deposited in the soil and hatch in a few days.
Small grubs feed during the first summer, moving down in the soil to over-winter.
The second summer they feed vigorously causing severe damage, then move downward to over-winter the second winter. They complete feeding the third year, then emerge as adults the next spring. Larvae are almost identical to larvae of other species, but are much smaller. Large numbers must be present before severe damage results. Adult ataenius over-winter in protective areas adjacent to turf.