Grape mealybug—Pseudococcus maritimus
Grape mealybugs are soft, oval, flattened insects. Their
bodies are distinctly segmented; divisions among the head,
thorax, and abdomen are not distinct. The adult female is
about 5 mm long and appears smoothly dusted with a white,
mealy, wax secretion. Long caudal filaments along the lateral
margin of the body become progressively shorter toward the
A new vine mealybug has
recently invaded California vineyards. This species has
shorter filaments than the grape mealybug.
Mealybugs excrete large quantities of sticky honeydew, which drips onto fruit clusters and later turns
black from sooty mold. Some berries may crack. Mealybugs do not injure vines.
Remove loose bark in winter; young mealybugs and eggs are concealed in such places until spring. High
temperatures in June kill much of the most damaging brood. Control
of ants (which interfere with natural
enemies) is important. Oils applied during dormancy can reduce numbers somewhat.