Main symptoms

Eutypa lata can develop several years in wood before leaf symptoms, attributed to toxin production, appear and signal the presence of the disease.

• Arm and trunk

Cross sections in the arms or the trunk of diseased stumps make it possible to observe a necrosis wood hard , brown in color, always sectorial and well delimited in the extension of a wound or a pruning area (figures 1 and 2). The wood gradually degrades to a dry, cubic-type rot and breaks very easily. The break obtained is reminiscent of that observed in the case of a core cut in half manually. In areas of dead wood, where the bark has exfoliated, grayish to blackish, bumpy areas are observed which contain globular fruiting bodies of the fungus, and in particular the perithecia (Figures 3 and 4).

• Vegetation and young herbaceous twigs

Unlike esca, the first noticeable symptoms during vegetation are observed in spring on young herbaceous twigs . All shoots from an infected arm or only a few show slow growth with short and more or less regular internodes (Figure 5). The leaves are, in general, small, often chlorotic, frizzy or twisted, sometimes jagged. Necrotic spots also form on the leaf blade which may then spread to the entire leaf. At a more advanced stage of the disease, the twigs often bear leaf blanks or even lack them altogether. At a final stage, the arm carrying stunted twigs may wither during the season.

• Inflorescences and clusters

The inflorescences sometimes dry out before flowering. Otherwise, they show an erect habit, show symptoms of coulure or millerandage. The clusters formed consist of small berries that are often apyrenic.