Cottony vine scale

Systematic position: The cottony vine scale (Pulvinaria vitis) belongs to the order Hemiptera and the family Coccidae (soft scales). It is a significant agricultural pest known for its distinctive white ovisacs produced by adult females during the reproductive period, which make them easily identifiable in the vineyard.

Host plants: This pest is polyphagous, meaning it feeds on a wide range of plants. While it is particularly destructive to grapevines, it also infests various deciduous trees and shrubs, including apricots, peaches, plums, hawthorn, linden, and maples, causing localized damage to woody tissues.

Biology and life cycle: The insect overwinters as second-instar nymphs within cracks in the bark. During the spring, they migrate to young shoots and leaves. After mating, females develop white, cottony egg sacs. By mid-summer, mobile nymphs, known as crawlers, emerge, disperse across the leaves to feed, and later return to the woody parts of the plant to settle for overwintering.

Damage and harm: Both nymphs and adult females extract large amounts of sap from the plant, which leads to stunted growth, leaf chlorosis, and general tree or vine decline. Furthermore, the excretion of honeydew attracts ants and encourages the growth of sooty mold, which coats the foliage and fruit, interfering with photosynthesis and reducing crop marketability.

• Pruning and destroying severely infested branches during dormancy.
• Scraping off loose, infested bark to remove overwintering nymphs.
• Applying horticultural oils in early spring to smother overwintering stages.
• Using contact or systemic insecticides during the peak crawler emergence period.
• Encouraging natural biological control by protecting predator populations such as lady beetles.