Name (also Blattgallenlaus, lat. Gallicola) for the above-ground on leaves of the Rebstocks occurring phylloxera; see there the complex life cycle.
This most dangerous of all vine pests (bot. Dactylosphaera vitifolii) is an insect of the order plant lice (Homoptera), subordination aphids (Aphidina) and dwarf family (Phylloxeridae). The phylloxera affects only the grapevine, sucks on the leaves and / or the roots and releases their saliva into the juice pathways what Gallen (Growths), which then serve as egg laying and food. Due to different behavior patterns towards the Rebstock different types are suspected. The German biologist Dr. Carl Börner (1880-1953) distinguished between a less dangerous long-nosed and a more harmful short-nosed phylloxera. From the first infestation, it lasts as a result of subsequent effects nutrient deficiency and root rot usually a maximum of three years until the vine dies and is completely destroyed. French scientist Jules Émile Planchon (1823-1888) the phylloxera gave the appropriate name "Phylloxera vastatrix" (devastating louse) when it was identified in France in 1868.
The life cycle is strong from the infested vine species, namely Europäerrebe or Amerikanerrebe dependent. It takes place either in the form of a complete cycle or continuous cycle between the vine (above ground) and root (underground) or only on leaves (only above ground) or only roots (only underground) and thus a shortened cycle. There are parthenogenetic (Virgin generation from unfertilized egg cells) and sexual generations. A distinction is therefore made between the yellow-green 1.5 mm long aphid (Gallicola = leaf gall louse) and the yellow-brown 1.35 mm long red vine (Radicicola = root louse). The latter is much more dangerous since it is the one Xylem damages, which leads to water and nutrient deficiency. The infestation of leaves is usually not life-threatening. In the grape species there are some that form both leaf and root galls, but the root galls do not form leaf galls, and the leaf galls do not form root galls. The group of the perfect resistant Vine species form neither leaf galls nor root galls.
In Europe, only the propagation through the root lice occurs, while the full cycle takes place only in America. Only in the above-ground cycle do offspring with new genetic material arise, since there are only males and females here. In root lice, there are only females that reproduce parthenogenetically and lay 600 eggs. Young hatched do not immediately attack the roots, but hibernate deep in the ground. In the spring, the roots are pierced with the trunk (half the length of the body) and the saliva is introduced into the tissue. As an almost panicky defense reaction of the vine, gnarled growths develop. The lice then feed on these soft structures and soak them up. The pest can only live through the formation of bile, because the hard roots themselves could not be gnawed at directly.
In Central Europe there are four to six generations of phylloxera each year. The last generation of young lice (Hiemalen) form the wintering form. Towards the end of midsummer, nymphs develop, which are larvae with wing tips. These leave the ground and develop into winged phylloxera (Sexuparae) after their last moult. Thanks to their ability to fly, they can quickly spread to other vineyards over long distances. They lay small male and large female eggs on the perennial bark of the vine, from which the nodular sex animals (Sexuales) hatch. These cannot take in food and only have the task of copulation during their only eight days of life.
The mated females lay a single fertilized olive green winter egg in a bark crack. From this spring the Maypole lice hatch, which form leaf galls only in American vine species (Vitis vinifera is resistant to the leaves) and lay up to 1,200 eggs. Two larval species hatch from this after eight to ten days. Some form leaf galls again, especially on younger leaves. They multiply parthenogenetically with six to eight generations a year. The others are leaf-born root lice and look for the vine roots in the ground. There they complement the underground development cycle or start it again. A wintered phylloxera with 1,000 eggs results in around 25 trillion offspring by autumn. The tremendously complex cycle or life cycle of leaf vine and root vine is shown in the graph:
A distinction is made between two types of roots and thus different effects from the infestation. If there is less infestation, the young, woodless root tips are pierced first. The resulting root gall is called Nodositäten, They occur not only in the European, but also in most American grape species, but they are relatively harmless and do not lead to destruction. With larger infestations, however, the older, woody roots are pierced and as a result the tuberosities educated. These are much more dangerous because they can penetrate much more deeply into the roots' vascular system. Certain American vine species are immune to both, which is the most resistant Vitis...