Main symptoms
Elsinoë ampelina is responsible for symptoms on vines quite comparable to those caused by excoriose , so beware.
- Leaves
This fungus first causes small wet spots on young leaves, a few millimeters in diameter (1 to 4 mm) and brown to chocolate brown in color (Figures 1 to 3). These are subsequently circular to angular, extend progressively and can reach half a centimeter (figure 4). They remain isolated or converge and cover important sectors of the limbus (Figure 5). They sometimes present a more or less marked chlorotic halo.
These spots are often localized along the veins (Figure 2). At the end of the development, the central tissues tend to necrosis, lighten (greyish-white coloration) (figure 6) and dry out. They eventually fall off, giving the blade a riddled appearance (Figure 7). On young leaves, when numerous lesions develop along the veins, more or less severe leaf deformations and / or mortalities may be observed.
- Young shoots and twigs
Localized and elongated lesions form on young herbaceous twigs which are particularly sensitive; moist, elliptical in shape and varying in color between brown, black and purple, they can modify the development of young shoots (Figure 8). They extend and progress in depth, reaching the marrow. At the end of the development, these lesions spread and become clearer in their center (figure 9); they can give rise to more or less marked and severe hollow cankers, making the twigs more brittle or causing them to dry out and die (Figures 10 and 11). Lesions on petioles and tendrils are identical (Figure 12). Such lesions can be observed on woods in winter (figure 13).
Confusion of diagnosis can occur with hail damage.
- Bunches and berries
Circular and slightly concave brown spots appear on the young berries disrupting their growth (Figure 14). They have the shape of a bird's eye (the Anglo-Saxons speak of bird's eye rot); sometimes lighter in their center, they have a rather purplish black color on the periphery. When attacked early, young clusters can turn black and dry out (Figures 15-17).
High mortalities of inflorescences (figure 18) and twigs were observed.