The Japanese Beetle is the adult life stage of a common destructive white grub species found in Canada. The Japanese Beetle is one of many white grubs species that attack lawns and it is important to identify which species is which. The adult Japanese Beetle has a distinctive metallic emerald coloured head, and copper coloured wings. Each wing has 6 tufts of white coloured hair along each edge. Although its appearance is stunning, the damage they can create to plant material is anything but.
Adult Japanese Beetles lay their eggs in Late July through early August and during this period beetles are commonly seen mating together in large groups. Although the the Japanese beetle doesn’t cause any damage to the lawn during this stage of its life cycle, gardens, flower beds, plants and trees certainly feel the effects. Japanese Beetles aggressively feed on plant materials causing extensive damage when infestations are high. The beetle chews away at the leaf tissues to the point where complete defoliation of the deciduous plant material has taken place.
The damaging life stage of the Japanese Beetle life cycle is when the white grub is a larvae. The adult beetles lay their eggs in late July into August, and the eggs hatch shortly after. Larvae feeding begins in late August, and continues into late fall before the white grub overwinters as a 3rd instar larvae. The larvae live in the soil and feed on the roots of the lawn. Signs of damage typically start with areas of the lawns browning out and developing into large dead patches. Additional damage is caused by animals such as raccoons, birds and skunks ripping, tearing and digging the lawn up as they search and feed on white grubs.
Grub control applications target the larvae life stage of the white grubs life cycle so timing is critical to prevent not only larval grub damage to the lawn, but adult beetle damage to plant materials.