Eutypa lata  (Pers.) Tul. & C. Tul. 1863

Eutypiose

The most recent molecular identifications have revealed a great variability between isolates which have been organized into groups of haplotypes, rather than suggesting distinct species or subspecies.
Eutypiosis is one of the most recent diseases identified in grapevine. This wasting disease is caused by the growth in wood of the woody fungus E. lata *. It has been reported in most of the major wine-growing countries of the world. Its incidence and severity fluctuate depending on the region, they seem to be closely linked to:

• The rainfall which governs the wetting of the wood and therefore the formation of perithecia
• The sensitivity of the grape varieties
• Rigor in the application of prophylactic measures.

This disease "exploded" over the entire French vineyard at the end of the 1970s. Over the period 2004-2008, the results of the National Observatory "Wood diseases" show that 50% of the vineyard plots visited show leaf symptoms of eutypia. The average frequency per plot of vines expressing symptoms varies between 3% and 4%. This relatively low average in fact masks a very great variability in the expression of eutypiosis depending on the plots, the age of the vines, the grape varieties and the years. For example, in the Cognac region between 2004 and 2006, more than 20% of Ugni blanc vines showed leaf symptoms.

Eutypiosis, also called in English "disease of the dying arm", is an economically expensive disease especially for winegrowers concerned with maintaining the qualitative potential of their wine heritage (purchase of complants, cost of prophylaxis). Indeed, this disease obliges them to cut the diseased parts or to replace the dead vines. The plots become heterogeneous, sometimes too rejuvenated or unbalanced grape varieties (introduction of resistant grape variety) which contributes to depreciating the quality of the wines. Even more serious, the harvest volume is often maintained by overproducing healthy vines, despite many missing strains.

Note that eutypiosis would also lead to a loss of varietal aromas in Sauvignon, even slightly affected. 

- Classification : Fungi, Ascomycota, Pezizomycotina, Sordariomycetes, Xylariomycetidae, Xylariales, Diatrypaceae
- Synonyraes : Sphaeria broad Pen., (1796) ; Eutypa apricot Matsush. 1005 & Carter, (1957)
- English denominations : Eutypa dieback, Eutypa, dying arm disease, toothache, eutypiosis

* Recent studies carried out in the United States, Australia and South Africa have shown that other pathogenic species belonging to the Diatrypacae family were isolated from vines: Diatrypella spp. , Eutypa leptoplaca (Mont.) Rappaz 1987, Cryptovalsa ampelina (Nitschke) Fuckel 1870, complicating the parasitic context of wood diseases.