Grape wilt

from Wikipedia, the free encyclopedia
Wilted berries on a grape of the Zweigelt variety damaged by wilting

The grapes wilt , even Beer wilt or Zweigelt disease called, is in the 1990s for the first time in the grape variety Zweigelt in Burgenland occurred. During the ripening of the grapes, it leads to sudden slackening of the grapes and disturbances of ripeness. These grapes are no longer suitable for winemaking . This results in a sometimes considerable economic damage, which is not limited to the Zweigelt variety. These wilting phenomena already occur in several grape varieties from Europe and America. The disease is a physiological disorder and is classified as wilt diseases .

Damage

The typical damage caused by grape wilts are malfunctions in the ripeness of the grapes (poor color, lower must weight and increased acidity), sudden slackening of the berries (loss of turgescence) and discoloration of the leaves on individual shoots. This disease affects the grapes from the start of ripening. The first characteristic can be delayed or poor coloration of the berries. Often diseased grapes are also small berries. The grapes can also develop normally, but in the event of an illness, the turgescence (occurring during the entire ripening phase of the grapes) diminishes more or less quickly , causing the berries to wilt. Often the loss of turgescence comes before the slack becomes visually noticeable. This loss can be felt by touching the grapes. The withering of the berries can occur on the whole grape or on parts of the grape (especially the tip of the grape). In contrast to the symptoms of stalk paralysis, no external necrosis can be found on the stalk structure . When the grapes are ripe for reading, the grape structure and the berry stalks z. T. dries up and the berries fall off easily. It is also noteworthy that both healthy and diseased grapes can be found on a fruit cane.

If the disease is severe, the leaves usually also show symptoms. In some cases, necroses (signs of death) form between the leaf veins, which are surrounded by a red border in red wine varieties. This damage pattern is similar to Esca disease , which can be confused. Depending on the circumstances or the nutrient supply, the symptoms of a potassium deficiency can be determined.

The disease occurs annually with very different intensity and regionality. The occurrence in vineyards is also subject to annual fluctuations, affected vines can bear completely healthy grapes in the following year and vice versa. Even in locations with a good supply of potassium and magnesium, the grapes can wilt.

Due to the characteristics of this disease (low must weights, increased acidity of the diseased grapes), these grapes are not suitable for processing.

  • Wilted Zweigelt grapes are cut to the ground during harvest.

  • Typical leaf symptom on a vine where grape wilt occurs heavily (Zweigelt)

  • Typical leaf symptom of a vine that is infected by ESCA

  • ESCA infestation of a vine - typical of the infestation is that parts or d. entire floor are affected.

causes

The cause of grape wilt is a physiological disturbance in the development and ripening of the grapes, which is controlled in a complex manner. Depending on the location and soil conditions, the causes are different. One factor acts at one location and another factor as the trigger (cause) of grape wilting at another.

The cause is varied and is made up of several factors (complex of causes). Therefore the elimination is not easy to carry out or successful. In addition, the cause complex has not yet been adequately researched. The following are currently known as causes or triggering factors or their interaction: The listed order has no preference for the cause.

  • Insufficient supply of potassium particularly in the subsoil
  • Unfavorable (potassium / magnesium) K / Mg ratio of less than 1.7: 1, especially in the subsoil (if the K / Mg ratio is between 1.7: 1 and 5: 1, this is to be assessed as favorable)
  • low or inharmonious supply of nutrients due to insufficient fertilization and / or difficult nutrient absorption conditions due to prolonged drought (drought stress , nutrient stress )
  • Hidden (latent) potassium deficiency can be triggered by excessive nitrogen supply (strong growth) or an unfavorable nitrogen: potassium ratio.
  • unfavorable nitrogen / potassium ratio
  • excessive water supply
  • strong growth
  • Extreme weather situations (strong energy irradiation with simultaneously low air humidity during the berry size development or severe overheating of the grapes in the ripening phase with short-term insufficient water replenishment, longer stress phase, e.g. several days of rain or persistent cool weather)
  • Water and nutrient competition if the greenery is not adapted to the soil and weather conditions
  • Stress due to constant overloading of the cane for several years (low reserve material potential)
  • Soil compaction (limited root space or growth, lack of oxygen)
  • Stress from intensive interventions in the canopy wall - unfavorable leaf / fruit ratio, especially if the BFV rises above 0.8.
  • Compared to Kober 5 BB, the underlay type SO4 is more sensitive to drought stress and has a lower magnesium absorption capacity; this makes it more susceptible to grape wilt (if it is dry) and stalk paralysis (if there is a magnesium deficiency).
  • Indications that global warming is a contributory cause of grape wilt have not yet been confirmed and are currently excluded.
  • Annual weather pattern

The complex of causes is currently the subject of intensive research in Europe and the United States.

Elimination

The complex of causes makes rectification difficult. Depending on the given situation, very good, but also no reductions at all could be achieved. It requires a multifaceted approach, where the aim is to bring those factors into an optimal balance, where maintenance measures can be used to influence (nutrient supply, yield load, soil maintenance, foliage work) and natural stress factors (increased energy radiation, heat, rapid drainage of Extreme weather conditions, drought, excessive soil moisture) to mitigate their negative impact as far as possible. If the vineyard is given optimal development conditions, stress due to high yields, excessive defoliation and the root system can develop well in the soil, store sufficient reserves and, especially around the flowering period, can supply enough water and nutrients - special potassium - there is no grape wilt. A frequent cause is also an insufficient supply of nutrients to the subsoil (30 - 60 cm). An increase in the supply of nutrients in the subsoil is not possible in an existing vineyard. Only before setting up the vineyard is it possible to achieve optimal storage by turning the soil deeply. Particular attention must be paid to the nutrient potassium.

See also

Portal: Wine  - Overview of Wikipedia content on the subject of wine

literature

  • Karl Bauer, Ferdinand Regner , Barbara Schildberger: Viticulture . 9th edition. avBook published by Cadmos Verlag, Vienna 2013, ISBN 978-3-7040-2284-4 .
  • Horst Diedrich Mohr: color atlas diseases, pests and beneficial insects on the grapevine . Eugen Ulmer, 2005, ISBN 3-8001-4148-5 .
  • Helga Reisenzein, Friedrich Polesny, Erhard Höbaus: Diseases, pests and beneficial insects in viticulture. 5th edition. Österreichischer Agrarverlag, Vienna 2008, ISBN 978-3-7040-2319-3 .
  • Guidelines for appropriate fertilization in viticulture. 1st edition. AGES Institute for Soil Management, Vienna 2003.

Web links

Individual evidence

  1. ↑ Markus Keller: Grape wilt: also unsolved in the USA. In: Switzerland. Z. fruit growing. 7, 2008, pp. 6-8.
  2. ↑ Helga Reisenzein: The Zweigelt disease a new vine disease? In: The winemaker. No. 5, 1995, pp. 7-9.
  3. ↑ Helga Reisenzein: Zweigelt disease - occurrence, malicious image control. In: The winemaker. No. 6, 1999, pp. 25-26.
  4. ↑ Adel Fardossi: Strong presence of potassium deficiency in various wine regions in Austria. In: The winemaker. No. 10, 2000, pp. 6-12.
  5. ↑ Fardossi Adel: Physiological studies on vineyards and orchards with special attention to stress factors. Final project report. 2005.
  6. ↑ Helmut Redl: The grape wilt on the track. In: Deutsches Weinbau-Jahrbuch 2005. (56), Verlag Eugen Ulmer, pp. 83-90.
  7. ^ Karl Bauer, Ferdinand Regner, Barbara Schildberger: Viticulture. 9th edition. avBook published by Cadmos Verlag, Vienna 2013, ISBN 978-3-7040-2284-4 , pp. 425-429.
  8. ↑ M. Erhardt: Investigations on grape wilt. Thesis. University of Hohenheim, 2010.
  9. ↑ Helga Reisenzein, Norbert Berger: Studies on the Zweigelt disease in Austrian wine. In: Plant Protection Reports. Vol. 59, No. 2, 2001, pp. 67-78.
  10. ↑ Ferdinand Regner, Martin Mehofer: The grape wilt of the vine - background to the frequent occurrence. LFZ Klosterneuburg. In: The winemaker. No. 2, 2010.
  11. ↑ Guidelines for proper fertilization in viticulture. 1st edition. AGES Institute for Soil Management, Vienna 2003.
  12. ↑ Martin Mehofer, Ferdinand Regner: The grape wilt of the vine - background to the frequent occurrence. In: The winemaker. No. 2, 2010. (der-winzer.at)
  13. ^ T. Leichtfried, J. Altenburger, N. Berger, W. Fickert: Thinning and grape wilt. In: The winemaker. No. 6, 2010, Austrian Agency for Health and Food Safety, Institute for Plant Health; Vienna (der-winzer.at)
  14. ↑ E. Kührer, C. Gabler: The leaf wall on the test stand: The grape wilt and the leaf-fruit ratio. Viticulture School and Wine Management Krems, Austria. In: The winemaker. Volume 67, No. 5, 2011, pp. 24-27.
  15. ↑ Barbara Raifer: Findings on the occurrence of grape wilt in South Tyrolean viticulture. Land- und Forstwirtschaftliches Versuchszentrum Laimburg, 2011 Auer, Italy (rebschutzdienst.at ( Memento of the original dated December 1, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and remove then this note. , PDF; 48 kB), PP (rebschutzdienst.at ( memento of the original dated February 1, 2016 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to instructions and then remove this note. , PDF; 607 kB) @1@ 2Template: Webachiv / IABot / www.rebschutzdienst.at @1@ 2Template: Webachiv / IABot / www.rebschutzdienst.at
  16. ↑ Erhard Kührer: Possible influencing factors for the occurrence of symptoms of grape wilt. Weinbauschule Krems, Austria 2011. (rebschutzdienst.at  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this note. , PDF; 38 kB), PP (rebschutzdienst.at  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this note. , PDF; 4.3 MB)@1@ 2Template: Toter Link / www.rebschutzdienst.at  @1@ 2Template: Toter Link / www.rebschutzdienst.at  
  17. ↑ Kristina Bachteler, Monika Riedel: Studies on grape wilt and stem paralysis in southern Germany. Staatliches Weinbauinstitut Freiburg, Universität Hohenheim, Stuttgart, Staatliches Weinbauinstitut Freiburg 2011. (rebschutzdienst.at  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. pdf), PP (rebschutzdienst.at  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , PDF; 1.9 MB)@1@ 2Template: Toter Link / www.rebschutzdienst.at  @1@ 2Template: Toter Link / www.rebschutzdienst.at  
  18. ↑ Michaela Griesser, David Kreil, Astrid Forneck: Grape wilt near Zweigelt - first results of a transcriptome analysis. University of Natural Resources and Life Sciences, Vienna . pdf  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , PP . pdf  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Toter Link / www.rebschutzdienst.at  @1@ 2Template: Toter Link / www.rebschutzdienst.at  
  19. ↑ H. Redl: The grape wilt on the track. In: The winemaker. No. 6, 2008, pp. 6-10.
  20. ^ M. Knoll, D. Achleitner, H. Redl: Sugar accumulation in "Zweigelt" grapes as affected by "Grape wilt". In: Vitis. 49, 2010, pp. 101-106.
  21. ↑ Astrid Forneck, Michaela Griesser: State of research on grape wilt - Austrian and international update. University of Natural Resources and Life Sciences, Vienna. In: The winemaker. No. 3, 2009 der-winzer.at