Wine's world

The descent of polar air in the middle of last week swept across France and caused important destructions in vineyards and orchards.

More than the intensity of the cold, it is the extent (from the north to the south of France, including Corsica) and the duration (three consecutive mornings) that make this spring frost exceptional:

- on April 6: -5.0°C in Blois, -4.9°C in Chalon sur Saône, -4.8°C in Angers...

- on April 7: -5.4°C in Chalon sur Saône, -4.9°C in Tusson (Cognac), -3.2°C in Vendays (Médoc)...

- on April 8: -5.5°C in Prades (Hérault), -4.6°C in Castillon, -4.4°C in Mâcon, -4.2°C in Avignon...

The damage is certainly considerable, especially since the development of the vines had been accelerated by the summer heat of the last days of March (26.0°C in Paris on March 31).

The final results of these frosts - and of those in progress this week - will not be known before a fortnight when the buds will start growing again (or not?). But we already know that the Côte Rôtie appellation has been devastated with expected losses of -70% to -90%.

Two studies have recently demonstrated a protective effect of wine compounds against coronavirus:

- American researchers discovered last January that polyphenols in grapes and wine prevent the virus from attaching to human cells (www.vitisphere.com/news-93204).

- More recently, the Taiwan Medical University found that tannins in wine inhibit two key enzymes of the virus, preventing it from entering cell tissue.

No hasty conclusion about the benefits of a hydro-alcoholic solution for internal use...

The Ministry of Agriculture [source Agreste] has published the quantity of plant protection products used per unit of surface area in vineyards in 2016.

Here are the results per wine-growing region (IFT = treatment indicator) :

- 21.50 IFT in Champagne, penalized by its chalky soil which retains moisture
- 18.00 IFT in Burgundy
- 16.40 IFT in Beaujolais
- 15.50 IFT in the Gers (Armagnac)
- 14.70 IFT in Charente (Cognac)
- 14.30 IFT in Bordeaux
- 13.60 IFT in Alsace
- 13.10 IFT in the Val de Loire
- 12.20 IFT in Dordogne

Then come the Mediterranean regions, favoured by their warmer, dryer and windier climate, less suitable for mildew and oïdium:
- 10.60 IFT in Languedoc
- 8.90 IFT in Provence and Southern Rhône (Châteauneuf du Pape)
- 7.60 IFT in Bouches du Rhône (Bandol)
- 6.90 IFT in Roussillon