Identification Symptoms
- This fungus can infect all green parts of the vine including
leaves, tendrils, new shoots, as well as berries. However, mature leaves
and ripe fruit are not susceptible. Infections of leaves first appear as
red spots on the upper leaf surface in late spring.
- These circular spots enlarge and become tan to light brown with
distinct, dark borders. Small, pinpoint black fruiting structures of the
fungus often develop in the centers of these spots.
- Most serious damage usually occurs on the berries. On the fruit,
infections first appear as whitish spots which enlarge to sunken areas
with dark borders. Significant infections usually occur when the grape is
pea-size or larger. As infection progresses, the fruit becomes black,
wrinkled, mummified, and look like raisins. Infected grapes often
shatter,leaving only the stem.