Esca is a destructive disease that affects grapevines and can cause significant damage to vineyards. It is caused by a complex of fungi and can lead to the decline and death of grapevines. Here are some symptoms of Esca that you should look out for in grapes:
- Leaf Symptoms: Esca typically causes various leaf symptoms, including discoloration, necrosis (death of leaf tissue), and the development of brown or reddish-brown streaks or patches on the leaves. These symptoms often start at the base of the shoot and progress towards the tip.
- Wood Symptoms: Another characteristic symptom of Esca is the presence of dark streaks or necrotic lesions in the wood of the grapevine. These streaks may extend from the trunk into the cordons and canes.
- Fruit Symptoms: Esca can also affect the grape clusters. Infected berries may show discoloration, browning, or blackening of the rachis (the stem of the cluster). In some cases, the entire cluster may wither or shrivel prematurely.
- Trunk Symptoms: As Esca progresses, it can cause visible symptoms on the trunk of the grapevine. These symptoms include wood discoloration, formation of black sunken lesions, and white mycelial fans (fungal growth) at the base of the trunk.
- “Tiger Stripes” or “Tiger Leaves”: Some grapevine varieties may exhibit distinct striping patterns on the leaves, resembling tiger stripes. These patterns are caused by the blockage of vascular tissues within the vine due to fungal infection, leading to irregular water and nutrient distribution.
It’s important to note that these symptoms may not always be definitive indicators of Esca, as they can resemble symptoms of other grapevine diseases. If you suspect Esca in your vineyard, it is recommended to consult with a professional viticulturist or plant pathologist for a proper diagnosis and appropriate management strategies.
