Although not a greenhouse pest, Oriental beetles can be found feeding on plants in outdoor retail yards, cut flower fields and home gardens. Oriental beetles are active during the day and night. The beetles are smaller than Japanese beetles, and usually are mottled gray with black blotches. The pattern and color varies. Oriental beetles have a long flight period, through early August and are very mobile. The white grubs feed on the roots of turf, herbaceous perennials and woody ornamentals. Grub damage may be worse in drought years and in weedy fields.
Oriental beetles, like Japanese beetles have a one-year life cycle. Adults emerge from the soil around the last week of June to feed and mate. The females burrow into the soil to lay eggs, usually in July. Eggs hatch into grubs and begin feeding on roots of grasses and other plants. They continue to feed until the soils cool down in September. In late fall the grubs migrate downward through the soil profile, staying below the frost line throughout the winter. In the spring as the soil warms, the grubs move back into the root zone and resume feeding. The grubs pupate in the soil before emerging as adults.
Contact insecticides can be applied as soon as the adult beetles are observed. Many of the contact insecticides may be harmful to bees, predatory mites and insects. Apply grub control to larvae in grassy areas surrounding the production areas.
