Definition - What does Lesion mean?
A lesion is a small area of visibly dead plant tissue. Lesions tend to indicate when there is a problem with the vines. A wide variety of diseases, from fungi to bacteria, produce lesions as one of their symptoms. The appearance of a lesion is what will help the winemaker determine what type of disease the vine is facing, so that he or she can take the appropriate steps to save their crop.
WineFrog explains Lesion
Lesions are a symptom of various vineyard diseases. The following diseases produce lesions as a symptom, which appear on the vines as follows:
- Anthracnose (Bird’s eye rot) Elsinore Ampelina - dark red or grey lesions on the grapes; lesions also appear on the leaves, shoots, tendrils, fruit tens and leaf stems
- Black rot Guignardia bidwellii - brown lesions on the leaves
- Botrytis bunch rot (Gray mold) Botrytis cinerea - brown lesions on the stem early in the season
- Leaf spot (Phomopsis cane) Phomopsis viticola - dark lesions on canes and leaves; lesions on shoots
- Young vine decline Phaeoacremonium, Togninmia minima, Togninmia californica - purple lesions on fruit
Winemakers use the color and location of the lesions to determine the cause and then develop a treatment plan.