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Daktulosphaira vitifoliae (=Viteus vitifoliae)
Grape phylloxeraOn this page: Identification & Distribution Other aphids on the same host Damage & Control
Identification & Distribution
The grape phylloxera (Daktulosphaira vitifoliae) is an important pest of commercial grapevines. When on its native vines in America, its life cycle takes two years to complete and includes a sexual stage. The single overwintering egg on vine hatches in spring to give the fundatrix. As the immature fundatrix feeds, she injects saliva into the leaf which induces a hairy, scabrous gall on the leaf underside (see first picture below) which opens on the upper surface. On reaching maturity the fundatrix lays eggs parthenogenetically in the leaf gall (see second picture below). The nymphs that hatch from these eggs move to other leaves where they produce 3–4 asexual generations of grape phylloxera.
Both images above copyright Claude Pilon, all rights reserved.
The adult apterae of Daktulosphaira vitifoliae are yellow (see picture below). The body is pyriform (=pear-shaped) with the broadest part anterior. The antennae are very short, with only 3 segments.
Image above copyright Claude Pilon, all rights reserved.
As the season progresses, some of the wingless females move to feeding on the roots. On vine roots the grape phylloxera induce bird's head-like galls, termed 'nodosities', on young expanding roots and cause hyperplastic growth (=excessive cell division) of lignified roots, termed 'tuberosities'. (The first picture below shows both the galls and white tuberosities.) Their offspring (see second picture below) spread to other roots of the same vine, or to the roots of other vines through cracks in the soil. Successive asexual generations of apterae persist on roots. The generation of nymphs which hatch in the autumn hibernate in the roots and emerge next spring when the sap begins to rise.
Both images above copyright Joachim Schmid under a Creative Commons Attribution 3.0 Germany License.
In the eastern US the root-feeding wingless females then produce winged individuals (alate sexuparae) from mid-summer to late autumn. These emerge from the soil to migrate and produce non-feeding sexuales: males, and oviparae (females), which in turn mate. The ovipara then lays the single overwintering sexual egg in the bark of the vine's trunk and then dies. It is this egg that gives rise to the leaf-inhabiting forms.
The grape phylloxera was introduced to Europe in the late 1850s where it destroyed many vineyards growing the common grape vine (Vitis vinifera). However, the life cycle of the phylloxerid is much simplified on the European vine. The sexual stage is lost, so there are no leaf galls and the grape phylloxera is anholocyclic on these vine roots. Forneck & Huber (2008) review the varied life cycles of the grape phylloxera. Leaf galls can occur in Europe on cultivars derived from hybrids between Vitis vinifera and American vine species. Daktulosphaira vitifoliae is now found in many parts of the world including North, Central and South America, Europe, the Mediterranean, the Middle East, Africa, China and Australia.
Other aphids on the same host
Daktulosphaira vitifoliae has been recorded from 11 Vitis species (Vitis aestivalis, Vitis berlandieri, Vitis candicans, Vitis cantoniensis x champini, Vitis cinerea, Vitis cordifolia, Vitis labrusca, Vitis riparia (synonomised by Blackman with Vitis vulpina), Vitis rotundifolia, Vitis rupestris, Vitis vinifera, Vitis vulpina).
Damage and control
The root form of Daktulosphaira vitifoliae is especially damaging to grape vines. The phylloxera perforate the root to find nourishment, infecting the root with a poisonous secretion that stops it from healing. This poison eventually kills the vine. Most native American grapes are naturally phylloxera resistant, but the European wine grape Vitis vinifera is very susceptible. This resulted in widespread devastation of European vineyards when the pest was introduced.
Attempts at control of grape phylloxera using insecticides were generally unsuccessful, and two alternative approaches have been utilised. One which gained favour in the late 19th century was the use of hybridization, in other words crossing the susceptible European Vitis vinifera with a resistant American species, usually Vitis aestivalis, Vitis rupestris, Vitis riparia or less commonly Vitis lebrusca. Such hybrid varieties are still widely grown in some parts of America, but are much less popular in Europe.
The approach currently favoured over most of the world is grafting Vitis vinifera onto a resistant rootstock. This has the advantage that the rootstock does not affect the flavour of the grapes and resultant wine.