Flavescence dorée

The golden yellow yellowing (French: flavescence Dorée ) is a Vine disease that belongs to the family of yellowing diseases in viticulture. It is regarded as first reported Vine disease, which is due to an infection caused by phytoplasmas. It was first observed in 1949 in the Armagnac region of the grape Baco Blanc.

As phytoplasma Candidatus phytoplasma pathogens the vitis was isolated. The only known vector is the American Rebzikade ( Scaphoideus titanus ). The pathogen multiplies in both the infested vine ( in the secondary phloem ) as well as disease carriers.

Dissemination

For a long time the spread of the American Rebzikade to the south of France ( Languedoc -Roussillon, Aquitaine, Midi -Pyrénées ) and to the north of Italy is limited .. the beginning of 1990, the spread of disease transfer agent seemed to slow down. 1999 new cases in the department of Gironde reported - but were in France in 1997. In 2004, the cicada was also first seen in Austria ( Southern Styria ). 2009, the disease in southern Styria by the Austrian Agency for Health and Food Safety (AGES ) has been demonstrated.

Symptoms

The first affected by the gold Yellow yellowing vine disease symptoms form the entire floor. In addition to the yellowing of the Reblaubs ( while the foliage of white grape varieties actually yellowed, it turns on red varieties early reddish ) there is a necrosis of the affected areas later. The new drive axles woody incomplete, so that it can come to winter damage to the young shoots. If the infestation of vine was early, there is a strong coulure of flower. Otherwise, shrink the berries and grapes dry up. When shrinking the berries provides, moreover, a very bitter taste.

The extent of the observable symptoms depends on several factors:

  • The severity of the infection,
  • The vigor of the rootstock,
  • The Bordeaux grape varieties Cabernet Sauvignon and Sauvignon Blanc, as well as Sangiovese, Chardonnay, Aramon and Alicante Bouschet show symptoms in a pronounced manner, while Merlot and Semillon react only weakly.

A final indication of the disease provides a laboratory test such as ELISA ( = the immunological methods enzyme-linked immunosorbent assay). Can be mistaken for the Yellow Gold yellowing with black wood disease.

The symptoms are not yet visible in the infection. They occur at the earliest in the following year, sometimes even only 5 years later. Seemingly healthy vines can thus have long ago become infected with the phytoplasma. Rootstocks usually show no symptoms, so that an inspection prior to the sale of goods is urgently indicated.

Follow

All infected vines must be removed from the vineyard. The carriers of disease, the American Rebzikade can be controlled by insecticides. In France and Italy, a combat Yellow Gold yellowing is required by law because the economic damage can be significant.

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