Name for bile-like, yellowish and two to four millimeters large tumors in a bird's beak-like form (nodos = nodular), which in phylloxera be induced on the young, yet unpolluted roots. They are opposite to the much more dangerous ones tuberosities (scabby tumors on old roots) usually relatively harmless. Nodosities are also present in large numbers in most American species such as Vitis cinerea var. Helleri (Vitis berlandieri), Vitis riparia and Vitis rupestris formed, but a phylloxera infestation induces no tuberosities there. As long as only nodosities are formed, the survives Rebstock the phylloxera infestation mostly relatively unscathed.
This is not just for the American but also for the European species. The phylloxera can feed on the Nodositäten very well and multiply in abundance and infest also older roots if necessary. Refined vines tolerate the phylloxera, but they are therefore not free of it, but may even have a very high infestation, without causing root damage. Therefore, the susceptibility to nodosities in the selection of new documents previously not respected or too little.
Since it is feared that more aggressive phylloxera strains could soon develop, which could also damage the roots of grafted vines, one tries to breed more resistant to rape. Especially suitable as crossing partners are the two species Vitis rotundifolia and Vitis cinerea which, in contrast to most of the others mentioned above, do not form any nodosities or tuberosities, ie completely resistant are so that the phylloxera can no longer feed on their roots. Since the grafting on documents of Vitis rotundifolia does not work, because the scions Vitis cinerea has become increasingly prominent. One of the few proven in the practice and successfully introduced documents based on the species Vitis cinerea with complete resistance to phylloxera is the variety Börner, after their breeder Carl Börner (1880-1953) is named and by Dr. med. Helmut Becker (1927-1990) was tested and introduced. This base is 100% resistant to re-flow, but also very sensitive to limescale and can therefore only be used on lime-poor soils.