phylloxera

Phylloxera refers to sap-sucking insects in the genus Daktulosphaira (formerly Phylloxera) that attack grapevines (Vitis spp.). The most economically important species on wine grapes is Daktulosphaira vitifoliae. Phylloxera has two main forms: a leaf-galling form that induces galls on the undersides of leaves, and a root-feeding form that colonizes grapevine roots, causing root galls and disrupting water and nutrient uptake.

Originating in North America, phylloxera was accidentally introduced to Europe in the 19th century, where it caused the Great French Wine Blight and widespread vineyard devastation. Many Vitis vinifera cultivars are highly susceptible to root-damaging forms, while native American Vitis species are more resistant. The crisis prompted a major shift to grafting V. vinifera onto resistant rootstocks and spurred global quarantine and breeding programs.

Biology and symptoms: Phylloxera has a complex life cycle featuring leaf and root generations on different tissues. Leaf galls appear as small patches and distort leaf shape; root galls disrupt the plant’s ability to transport water and nutrients, leading to reduced vigor, lower yields, and eventual decline. The pest persists in soil and spreads via infested plant material, soil movement, and equipment.

Management and status: The use of resistant American rootstocks remains the primary control method. Quarantine, sanitation, and careful monitoring help limit spread. Chemical controls offer limited effectiveness, and integrated pest management approaches are used to minimize damage. Phylloxera remains a ongoing concern in many wine regions, though its impact is mitigated where resistant rootstocks are employed.