Phylloxera

Grape phylloxera (Daktulosphaira vitifoliae (Fitch 1855); family Phylloxeridae); originally described in France as Phylloxera vastatrix; equated to the previously described Daktulosphaira vitifoliae, Phylloxera vitifoliae; commonly just called phylloxera ( /fɪˈlɒksərə/; from Greek φύλλον, leaf, and ξερόν, dry) is a pest of commercial grapevines worldwide, originally native to eastern North America. These almost microscopic, pale yellow sap-sucking insects, related to aphids, feed on the roots and leaves of grapevines (depending on the phylloxera genetic strain). On Vitis vinifera L., the resulting deformations on roots ("nodosities" and "tuberosities") and secondary fungal infections can girdle roots, gradually cutting off the flow of nutrients and water to the vine. Nymphs also form protective galls on the undersides of grapevine leaves of some Vitis species and overwinter under the bark or on the vine roots; these leaf galls are typically only found on the leaves of American vines.