English name (short RW) for a group of vine wood diseases, presumably by virus caused. These include cork bark disease, stem scarring, as well as woodiness or sting pitting. The causes are not yet fully understood, presumably they are virus groups such as Grapevine clostrovirus A and B and various leaf roll Virus complexes. All these diseases at least lead to return - Reduction and significantly reduced lifespan vines, The transmission or spread of the diseases takes place (at least in Europe) mostly in the finishing through infected documents (Rhizomes) or scions (Top parts). Only in Mexico and the southern one United States is also one cochineal as transmitter (at Corky bark). The symptoms of the various diseases are very similar because wood and the bark are affected by the infection.
This is extremely dangerous because it is usually deadly to the vine. It seems to exist only in the US so far, but in Italy a similar disease called Legno Riccio (Wood-Locke) is known. Particularly typical is the swelling of the Inter Nodien at the engine base, associated with cracking. The leaves turn yellow and in red wine intensively red and roll (similar to the Leaf roll disease ) down. But they stay longer compared to healthy plants on the vine and fall off later. The wood is maturing very badly. The outer layers of the bark on the trunk are degraded. At the graft site swelling occurs, the upper part dies, while the rhizome often survives.
The disease manifests itself by exceptionally delayed expulsion, less growth with dwarfism and death of woody parts. The typical symptoms are thickening and cranking especially on older vines, a thick bark with a coarse surface and in the longitudinal direction scars, grooves (grooving), wrinkles or pitting (pitting). Here, too, the leaves turn intense red in red wines. If one peels the bark from the trunk in the area of the refining point, caverns (cavities) in the wood show up above all with the underlay. Due to a lack of reserve resources, the affected vines go to less favorable weather mostly one.
Disease is determined by the test procedure ELISA. Indexing or by means of PCR method, An accurate diagnosis is only possible by a test-processing on a specific sensitive (hypersensitive) pad. Most successful are the so-called green finishes, in which a green scion is grafted onto a likewise green, unrooted base. The symptoms of the disease are relatively rapid. In infested plants must have a clearing done in order to determine the disease accurately. The most suitable control method is health selection. In Austria was already in 1993 the project Certification of vines started. This should be done by appropriate analysis and selection of the most healthy vine material (certified Clones ) the quality is increased in the long term.
all pictures: WineLand South Africa