Also referred to as "Grapevine flavescence dorée phytoplasma", this relatively new vine disease probably evolved from the Great North Sea region of eastern North America in the 1940s Europe introduced. Massively she came here for the first time in the early 1950s in France - Armagnac on and then spread epidemically across southern France, Italy and Spain out. Especially hard hit Corsica because here are particularly vulnerable varieties be cultivated. It seems to be preferred in warmer areas, the strong spread may also be due to climate change or the climate change due. There were also several observations with similar symptoms Germany,
The disease is going through phytoplasmas (Bacteria-like microorganisms ), which are also the causative agent of elm yellowing. The pathogens are thought to be transmitted by at least two leaf hoppers (American varietal and oriental cicada) transmitted. The larvae stay mostly at the same time Rebstock and stay on the leaf undersides. The adult cicadas, however, are very mobile and can cause a rapid spread of the disease over long distances. Especially the grape varieties Alicante Henri Bouschet. Aramon Noir. Baco Blanc. Chardonnay. Riesling and Sangiovese seem to be vulnerable. The pictures show the advanced stage of the disease in the grape variety Scheurebe (Seedling 88).
The first signs show up in the early summer on the Scroll of the vines. These curl downwards and become bright golden yellow (hence the name "golden yellow yellowing") for white varieties and red for red varieties. The bills are very trickling and can completely dry out. To the Inter Nodien (Parts between the nodes of a shoot) form black pustules and sometimes also longitudinal cracks (see picture above). The shoots hang limp down as if they were wilting. In autumn form at the leaf main veins necrosis, If the infestation occurs in early growth, the grapes can also fall off. At least the berries shrink and take one bitter Taste. Delicate vine varieties can die completely one year after an infestation. Pathogens and cicada eggs are spread by seedlings. The cicadas are combated insecticides, A similar disease transmitted by cicadas is Pierce Disease,
golden yellow leaves: © H. Reisenzein - AGES Vienna
withered leaves: By Josef Klement, CC BY 2.0 at , Link
Instinctual Symptoms: By Josef Klement CC BY 2.0 at , Link
Leaf Symptoms: By Josef Klement CC BY 2.0 at , Link