This disease originating from the Middle East has long been known in Europe and the most widespread Rebvirose. It is caused by the Grapevine leafroll associated virus (GLRaV), which is found in the phloem of the leading tissue settles. Viruses as a cause of illness recognized the German vines breeder Georg Shy (1879-1949). The different ones virus (Closterviruses) are designated with a number, so far seven of them have been discovered (GLRaV1-7). The disease manifests itself in Europe starting in July, the symptoms are ever vine different pronounced. The leaves begin to discolor in all shades - red in dark and yellow in white grape varieties. A narrow strip along the leaf veins remains green. The sorts Blue Portuguese. Cabernet Franc. Chardonnay. Müller-Thurgau. Pinot Noir. Sylvaner and Traminer exhibit the characteristic symptoms at American vines but they are not visible.
Later, the leaves roll down so that in September, they only look like narrow triangles from the top. By the way, on the leaves too necrosis educated. Diseased vines form ever shorter and thinner ones shoots out. The flowers are strong Verrieseln, The negative effects include an increased blossom sensitivity, a delay of maturity, a lesser Mostgewicht as well as one Income reduction of 50% and more. The wine is re alcohol content. colour and taste negatively affected. When the for vascular disease and brushwood disease the responsible viruses can occur together, the disease symptoms can be much stronger.
The spread is made by infected documents and scions, as well as by virus transmission of Wollläusen and Vine mealybugs (the species Pseudococcus, Planococcus and Pulvinaria). A transmission by nematodes is excluded. The vines but are not destroyed and a stunt occurs rather slowly. Therefore, the dangerous disease is underestimated and fought too late. A direct fight in the stock is not possible. Indirect control is provided by careful control of the propagating stocks and exclusive use of healthy plant material. See also below Vine enemies,
Pictures and source: Maree et al. 2018 - Frontiers in Microbiology