Flavescence dorée damage symptoms
Symptoms of Flavescence dorée typically appear during summer and may affect individual shoots or entire vines.
Leaf symptoms
Discoloration:
- Yellowing in white grape varieties
- Reddening in red grape varieties
Morphological changes:
- Downward rolling of leaf margins
- Thickened and brittle leaves
Shoot symptoms
Growth abnormalities:
- Poor lignification
- Shoots remaining green and flexible late in the season
Physiological stress:
- Wilting of young shoots
- Cluster symptoms
Reproductive failure:
- Flower abortion
- Poor fruit set
Fruit deterioration:
- Shriveling of grape clusters
- Premature drying of berries
Molecular testing (PCR analysis) is required to distinguish Flavescence dorée from Bois noir symptoms.