This vine disease, which occurs mainly in very young vines, was first described in France in 1961. It is caused by a fungal complex of the genera Campylocarpon, Cylindrocarpon, Cylindrocladiella and Ilyonectria. The fungi colonize the xylem(leading tissue) and clog it. The effects are weaker shoot growth, reduced leaf mass and shortened internodes with chlorotic leaves. The roots are black-red discoloured with soft areas and may subsequently rot. The wood inside the rootstock may be discoloured red or violet.
The symptom that gives the wood its name only becomes visible when the trunk is cross sectioned. The inner xylem tissue turns black and often shows a brown spongy consistency. The name refers to the black-coloured, necrotic central cylinder of the base (see picture on the right). As a defence mechanism, the plant can develop secondary roots. Petri's disease shows similar symptoms. There are no effective measures to fight the disease effectively. It is promoted by stagnant wet, loamy soils and excessively fertilized vines. See also under fungi and vine enemies.
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