Golden yellowing
The golden yellowing ( French flavescence dorée ) is a vine disease that belongs to the family of yellowing diseases in viticulture . It is considered to be the first known vine disease to be traced back to an infection by phytoplasms . It was first observed in 1949 in the Armagnac region on the Baco Blanc grape variety .
The Phytoplasma Candidatus Phytoplasma vitis was isolated as the pathogen . The only known vector is the American vine leafhopper ( Scaphoideus titanus ). The pathogen multiplies both in the infected vine (in the secondary phloem ) and in the pathogen.
Symptoms
The vines affected by the golden yellowing initially develop symptoms of disease all over the vine. In addition to the yellowing of the vine leaves (while the leaves of white grape varieties actually turn yellow, red varieties turn red at an early stage), the infested areas later become necrotic . The new shoot axes lignify only incompletely, so that the young shoots can be damaged in winter. If the grapevine was infested early, there will be heavy trickling of the grain. Otherwise the berries will shrink and the grapes will dry out. When the berries shrink, they also have a very bitter taste.
The extent of the noticeable symptoms depends on several factors:
- the severity of the infection,
- the vigor of the rootstock ,
- the Bordeaux grape varieties Cabernet Sauvignon and Sauvignon Blanc , but also Sangiovese , Chardonnay , Aramon and Alicante Bouschet show the symptoms in a pronounced way, while Merlot and Sémillon react only weakly.
A laboratory test such as B. ELISA (= the immunological detection method enzyme-linked immunosorbent assay). The golden yellowing can be confused with the blackwood disease .
The symptoms are not yet visible in the year of infection. They appear in the following year at the earliest, sometimes even 5 years later. Apparently healthy vines can therefore be infected with phytoplasms for a long time. Rootstocks usually show no symptoms, so that a check is urgently indicated before the goods are sold.
Quarantine measures
All infected vines must be removed from the vineyard. The disease vector, the American vine leafhopper , can be combated with insecticides. In France, Italy and Austria, the fight against golden yellow is required by law as the economic damage can be considerable. For the plant disease , the pathogens and the vectors , movement bans and other measures for quarantine pests apply within the EU .
literature
- Jancis Robinson : The Oxford Wine Lexicon . Hallwag, Gräfe and Unzer, Munich 2006, ISBN 3-8338-0691-5 .
- Horst Diedrich Mohr (Hrsg.): Color atlas diseases, pests and beneficial insects on the grapevine . Eugen Ulmer, Stuttgart 2005, ISBN 3-8001-4148-5 .
- Pierre Galet : Les maladies et les parasites de la vigne, Volume 1 . Imprimerie du Paysan du Midi, Montpellier 1977, ISBN 2-87777-038-9 .
Web links
- Austrian Agency for Health and Food Safety (AGES), ages.at: golden yellow yellowing
- Badische-zeitung.de , Ortenaukreis , February 16, 2015: After the cherry vinegar fly, the vine leafhopper threatens
- proplanta.de: Protected area regarding golden yellow yellowing
- rebschutzdienst.at: Golden yellow yellowing
Individual evidence
- ↑ Notifiable organisms according to Directive 2000/29 / EG ANNEX II , pages 55 and 61 ( Memento of July 21, 2019 in the Internet Archive )