The relatively new vine disease, also known as "Grapevine flavescence dorée phytoplasma", was presumably followed in the 1940s from the area of the Great Lakes in eastern North America Europe introduced. She first entered here in the early 1950s France - Armagnac and then spread epidemically across southern France, Italy and Spain out. Was hit particularly hard Corsica, because here especially vulnerable varieties be cultivated. It seems to occur preferentially in warmer regions, the widespread distribution is possibly also due to climate changes or climate change due. There were also individual observations with similar symptoms in Germany,
The disease is caused by phytoplasmas (Bacteria-like microorganisms ), which are also the cause of the yellowing of the elm. The pathogens are probably transmitted by at least two leaf hoppers (American vine leafhopper and oriental leafhopper) broadcast. The larvae mostly stay the same Rebstock and stay on the underside of the leaf. The adult cicadas, on the other hand, are very mobile and can cause the disease to spread quickly over long distances. Especially the grape varieties Alicante Henri Bouschet. Aramon Noir. Baco Blanc. Chardonnay. Riesling and Sangiovese seem vulnerable. The pictures show the advanced stage of the disease in the grape variety Scheurebe (Seedling 88).
The first signs appear in early summer on the Scroll the vines. These curl down, turn bright golden yellow for white varieties (hence the name "golden yellow yellowing") and red for red varieties. The banknotes trickle very hard and can dry out completely. To the Inter Nodien (Parts between the nodes of a shoot) black pustules and sometimes longitudinal cracks (see picture above). The shoots hang limp as if they were wilting. In autumn the main leaf veins form necrosis, If the infestation occurs early, the grapes can fall off. At least the berries shrink and take you bitter Taste. Sensitive vine varieties can die completely as little as one year after an infestation. Pathogens and cicada eggs are spread through planting material. The cicadas are fought by insecticides, A similar disease, also transmitted by cicadas, is Pierce Disease,
golden yellow leaves: © H. Reisenzein - AGES Vienna
withered leaves: By Josef Klement, CC BY 2.0 at , Link
Drive symptoms: By Josef Klement CC BY 2.0 at , Link
Leaf symptoms: By Josef Klement CC BY 2.0 at , Link