The cover of the adult female purple scale resembles a mussel shell in shape. The immature male cover is shorter and much narrower than the female cover.
Mature males are winged insects that search out the immobile females.
After mating, females lay 40 to 80 eggs under the cover. After egg hatch, crawlers emerge from under the cover and settle on branches, twigs, leaves, or fruit and begin to form their covers. Two generations occur between May and October and a third may be partially completed before cold weather starts. It attacks all parts of the tree. This parasite develops externally on the body of immature scales under the scale cover.