When mature the adult beetle possesses a dark-brown to black body up to 16 mm long and has a unique set of antenna with large club-like ends. The underside of the body is covered in short grey hairs.
The Pruinose Scarab (Sericesthis germinate) larva is a white to creamy-white soft-bodied grub, up to 20 mm long with three sets of legs and a hard, light-brown head. With most scarab pests, the larvae can be difficult to identify between species as only subtle differences distinguish them from other beetle larvae.
Adults emerge from pupation under the soil in early spring, and often fly to eucalyptus trees to mate before returning to the soil to lay 20 to 40 eggs. The larvae then hatch and burrow into the soil where they remain for a period of eight to 10 months before emergence the following spring.
Larvae will mainly eat decaying organic matter, though in large numbers their minor feeding activities on plant roots can cause injury. Adults then hatch in spring and live for one to nine weeks.