Primo En Primeur knowledge last week from Emerson Ewald, Miranda Gustafson and Andres Larin. While I agree that eventually the system will go away, I don't think it's going to happen anytime soon as the courtiers hold a lot of power over the market still.
This week: Esca
How is this transmitted? What effects does it have on the vine? What are the solutions?
Esca is a fungal disease caused by multiple different fungi and it likely enters the vines through pruning wounds – it settles in the vascular tissue. Dark red and yellow stripes on the leaves is a sign of Esca, the disease can cause the wood of the plant to weaken and, eventually, crumble, killing the vine. Sodium arsenate was long used as a solution, but was banned in Europe in 2003. Some other solutions include Guyot-Poussard pruning which uses smaller cuts, removing the entire plant to keep it from spreading, and Fosetyl-Al (hoping someone on here knows more about this one and can explain it!).
Also worth noting that Esca can be spread through sloppy work in the nursery surrounding grafting just as effectively as through pruning, and like most fungal diseases can be spread by the spores kicked up in heavy rain or wind.
Esca, also called 'black measles', 'grape measles' and 'apoplexy', typically occurs in older vines (10 years and older). The fungi are somewhat weak and attack only wounded tissue thus the connection with pruning practices already mentioned.
Esca as of 2018 is the most problematic threat in the french vineyards, (Champagne and Loire valley especially). The only cure, since Sodium Arsenite has been banned (in 2001) & the rise of natural treatment, is to use a saw. Slicing through the root to extract the contaminated area and see if it survives. It touches mostly young vine up to 10 years and old vines +30 years in average. It has impacted 11% of the national grape vines. This rate continues its upward trend and has spread trough Europe (Spain, Central & South Italy) where 60-80% of the older vineyards are ravaged by it.
When I was in Chablis where this is also a huge problem Domain Laroche showed me how they use the saw method to remove infected material. They're having a pretty high success rate with this method.