Esca (and similar fatal wood diseases) is said to be affecting already at least 12% of France’s vineyards in the Mediterranean, the Loire and across the South West of France including Bordeaux, Armagnac and Cognac. Also found in California as Black Measles.
It particularly affects the Sauvignon Blanc and Cabernet Sauvignon grape varieties.
It is not a new disease. This wood-rotting fungus is ‘as old as the vine itself’ but its rate is increasing by 7% per year.
With intensive spraying affecting the immunity of the vine (and other crops such as olives) and with no available cure, it is spreading fast. Often in the prime of their life, the vine’s leaves turn yellow, yields fall and slowly the vine Withers and dies having already affected its neighbouring vines.
The only way of controlling the disease, the very toxic Sodium Arsenite, has been banned since 2001 and the French Agricultural Research Institute (INRA) and the French Vine Institute (IVF) are trying hard to find an alternative cure.
Meanwhile vineyards are being uprooted in an attempt to starve the fungus and avoid further contamination.
It seems that the disease is more prevalent in vinyards planted in soil devoid of any microbial bacteria due to years of eradiation due to conventional spraying. The higher the rate of Mycorization (the fungal activity on the roots of plants which enables the vines to live healthily with strong immune systems) the lower the risk of esca.
Vibration caused by electronic music is said to reduce the disease.