Grape mealybug
Pseudococcus maritimus
1 host plant
Last updated
Grape mealybugs appear as small, white, waxy-coated insects clustered on grape stems, leaf undersides, and around fruit bunches from midsummer through fall in warmer microclimates. The cottony wax coating is their most distinctive feature. Heavy infestations weaken vines, reduce fruit quality, and transmit plant viruses. Mealybug populations tend to build in protected microclimates and on stressed vines. You notice them moving slowly across surfaces.
Monitor vine foliage regularly starting in mid-summer for early detection. Remove heavily infested shoots where practical. A strong water spray can dislodge colonies. Apply horticultural oil or neem oil to dormant canes in late fall and early winter. Maintain vine vigor through watering and pruning. For active populations, insecticidal soap or spinosad targets crawlers.
Quick Reference
The adult female is wingless and can be up to 0.2 inch in length. It has a well-developed ring of waxy filaments around the sides of its body. The nymphs (or young crawlers) are purplish and covered with a powdery wax coating. As they get older, the coating gets thicker, and a fringe of wax filaments develops. Damage primarily results from the honeydew excreted by mealybugs. Honeydew is cast off in small drops and falls down through the canopy. When it lands on fruit it serves as a substrate...