The grape mealybug is white with a flattened, oval shape.
Filaments protrude along the perimeter of the body, the longest protruding from the rear.
First instar nymphs overwinter in a white cottony ovisac produced by the female in the fall. They become active in April or May, disperse over the vine, and begin to feed at bases of shoots or pedicels of grape clusters. Numbers are usually not high enough for damage to be caused at this point. Adults appear in late June and ovisacs containing eggs are deposited beneath loose bark. Young nymphs appear a few days later and may get into fruit clusters.