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.