How to Manage Pests

Pests in Gardens and Landscapes

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 head.

A new vine mealybug has recently invaded California vineyards. This species has shorter filaments than the grape mealybug.

Life cycle

Damage

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.

Solutions

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.

Adult Grape mealybug
Adult grape mealybug
Mealybugs on fruit
Mealybugs on fruit
Mealybug secretions
Mealybug secretions

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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