Oriental beetles generally take one year to complete their life cycles. Oriental beetles overwinter as third stage grubs deep in the soil. Grubs move back in the turf root-zone when temperature warms up early in the spring and begin feeding on turf roots until they become mature within 5 weeks. Matured grubs then pupate in the soil. Adult beetles then emerge from pupae by June. After mating, females lay eggs in the groups of over 20 eggs in the soil. Eggs hatch within 3 weeks into small grubs that feed on turfgrass roots and on the organic matter. While feeding, grubs complete three developmental stages (instars). Then third stage larvae move deep in the soil for overwintering and life cycle continues.