Morphological characters

0.5 à 1.5 mm.
Small orange to brown aphid. The antenae are short and the cornicles are absent.
Apterous : orange to brown, three-article antennae, cornicles absent.
Alate : brown, three-article antennae, cornicles absent, simple and undivided wing veins.

See identification file

Life cycles

Life cycle of Phylloxera is complex. It consists of a sexual and an asexual phase, but also a part on leaves and an other part on roots. This life cycle includes a large number of different morphs.

During spring, the fundatrices hatch and form new galls on leaves. They will lay a large number of eggs asexually, and several generations will follow. These are the gallworms. Some individuals migrate to the roots, they are named  neogallicoles-radicicoles.

On roots, aphids spend the winter period in the first larval stage. Individuals on roots are called radicicoles. Aphids lay eggs asexually, which give rise to new radicicoles individuals. After a few generations, winged individuals are produced. These individuals migrate to the aerial parts of the plant and lay eggs which give rise to male and female aphids. Alates laying male eggs are called androparae, individuals laying eggs containing females are called gynoparae*.

Males and females hatching from these eggs have no rostrum, so they cannot feed.  The only function they have is to reproduce. After reproduction, the female lays a single egg called the winter egg, which contains the future foundress who hatches the following spring.

Host plants

Vittis spp.

Particular characteristics

All morphs of this species lay eggs, they are oviparous.

Feeds on the contents of parenchymal cells.

Description of the different forms :

The apterous  forms :

•  The sexual morph : this morph is deprived of rostrum. After reproduction, the females lay a single egg which contains the future fundatrix and allows her to spend the winter.
•  The asexual morph :
  • The gallicole morph is the apterous morph that develops in the galls present on the leaves.
    • The neogallicole-gallicole morph will remain living in the leaf galls.
    • The neogallicole-radicicole morph will migrate to the roots to form root galls.
  • The radicicole morph is the apterous morph which develops in the galls present on the roots. Some of their eggs give birth to winged individuals
  • The fundatrices are the individuals hatching from winter eggs, they will form galls on the leaves where they will found a new colony.

Winged forms are produced by aphids developing on the roots. There are two types of winged forms. The androparae, which will lay eggs containing males and the gynoparae laying eggs containing females.*

* ''BALBIANI (1884), BÖRNER (1910 ff.) and several other researchers point out that the same winged can lay two kinds of eggs at the same time. GRASSI, on the contrary, maintains that in Italy some lay male eggs, others female. Our observations at Montpellier and Les Eyzies have always given us the same results: androphoric and gynephoric adults, with no distinctive morphological characteristics.'' (Extract from Pierre Maillet's thesis, 1957, Contribution à l'étude de la biologie du Phylloxera de la vigne). 

Agricultural impacts

The end of the 19th century was marked by a serious wine health crisis for French producers, caused by the importation from the USA of Phylloxera (now Daktulosphaira vitifoliae). Between 1863 and 1893, D. vitifoliae destroyed a very large part of the French vineyard and caused the disappearance of European grape varieties and vineyards. It seems that the importation of Vitis riparia, a wild American vine, was responsible for the introduction of Phylloxera into Europe.

Phylloxera causes indirect damage to vines. On the underside of the leaves they form reddish galls. The formation of galls leads to a decrease in leaf growth and chlorophyll production. The plant can no longer build up reserves for the winter and fruits are less sweet.

On the roots, aphid bites result in the formation of nodules or tuberosities that are partially necrotic. A bird's beak deformation occurs. Cracking occurs on the tuberosities leading to a decline of the infected vine of 2 to 5 years. European vines are more affected at the root level and leaf infestations are observed less frequently than in America.

One solution used to limit the spread of aphids in crops is to graft Vitis vinifera onto resistant rootstocks of American origin. Another solution is to grow the vines in sandy soil, which prevents the neogallicolous-radicolous individuals from descending to the roots to form new galls. Chemical control has little or no effect. It should be carried out early in the season to target individuals moving to form galls on the leaves. Eggs will be only slightly affected by chemicals and when egg production becomes important, this solution becomes very inefficient.

Natural enemies

Predators
Order

COLEOPTERA : COCCINELIDAE

- Coccinella septempunctata

NEUROPTERA : CHRYSOPIDAE

- Chrysoperla carnea

ACARI : ACARIDAE

- Rhizoglyphus echinopus

Parasitoids