“Life gives us much to worry about; and wine makes the worries disappear.”Johann Wolfgang von Goethe-
The Coronavirus has the whole world in its grip.
And how about viruses in the vineyard? What do we know about them?
In the vineyard, the winegrower has to deal every day with viruses and fungi that threaten his vines and grapes. In both cases, it’s the question: how do you prevent those viruses and how do you fight them. In this article, I will limit myself to the viruses in wine growing.
Most people know that there was once a major disaster that almost completely destroyed European vineyards, the Phylloxera. This took place in the 19th century. This was a grape louse that fed on the roots of the vines. The bite wounds he inflicted infected the vines in those areas and they died within a few years. There was a solution. American grapevines that evolved with this grape lice had developed a natural defense mechanism. A sticky juice that was released after a bite and stuck to the mouth of the grape louse and placed a protective layer over the bite wound at the same time. Enting the European grape varieties onto these American vines has largely curbed that danger.
Viruses on vines
Viruses on vines are usually not fatal but often affect the ability of the vine to function properly so that there is often no other option than to dig up the vines and disinfect the soil. Usually, viruses in the vineyard are spread through cuttings or microscopic worms that attack the roots. With cuttings of vines (also called clones), you create plants with the same characteristics. The risk is that you also multiply the viruses present. A modern solution is the cloning of the grape via tissue on culture. Here, virus-free growing tops are cloned in a laboratory. You can then graft it on a vine that is resistant to these small worms.
Insects and bacteria
What other dangers threaten the vine? Insects such as the sharpshooter, a family member of the cicada, transmit bacteria that can affect the grapevine by sucking the plant juices. There is little that can be done about this. Fortunately, vineyards in colder climates that sometimes have to deal with frost do not suffer from these insects. It is possible that natural enemies also can be used, such as the parasitic wasp, but I have not found any data on this yet.
And then there are the fungal diseases that can attack the vine. This mainly occurs when there are hot and humid environments. In Maritime climates, this situation naturally occurs as a standard. Mildew and Downy Mildew are fungi that a winegrower does not like to see on his green parts of the vine and on his grapes. Affected grapes taste less fruity and will taste moldy and bitter. As a solution, the winegrower can use a chemical spray. He normally uses this about twice or three times a season. Natural agents such as sulfur and copper dissolved in water are also available (the so-called “Bordeaux porridge”). This is even allowed being a natural substance in organic wine growing. The disadvantage is that you have to spray again after every moment of rain because otherwise these products are rinsed off the leaves. During a season it is necessary to spray about 12 to 16 times. Of course, this sulfur and copper also enter the soil and are undoubtedly absorbed by the vine. I’ll leave it to the consumer to judge what method is preferred.
The most important means is still the selection of the right grape variety for the particular climate and vineyard. It is wise to choose the grape variety that thrives best. With the right vine rootstock and clone variant. That’s all a winegrower can do. Except of course take good care of his vineyard and ensure that his vines are healthy.
Cheers, and take good care of yourself.
In addition, here are a number of articles that I found on the Internet.
1. On the Winespectator website, there is an article that indicates a signal when the sense of smell is decreasing. This could indicate an early indication of having Corona, according to the article. ( English)
2. The well-known wine exhibition center La Cité du Vin (www.laciteduvin.com/fr), in Bordeaux, has closed due to the Corona crisis. But they still have a lot of information online. A lot can be heard about the wine culture in the world. ( English and French) Watch and listen: https://soundcloud.com/laciteduvin
3. On the website of De Wijnhoek, I found a lot of information about damage to wine grapes. (Also in English.) http://www.dewijnhoek.nl/database/info83.html