🦠 Pierce's disease

Pierce's disease is a grape disease caused by the bacterium Xylella fastidiosa. The bacterium settles in the vine's vessels and blocks them. Water and nutrients stop reaching the leaves and berries. Leaves yellow and dry at the edges, berries shrivel, and the vine eventually dies.

The bacterium is carried by insects. These are leafhoppers (sharpshooters) that feed on plant sap. They fly from plant to plant and pass on the disease. The disease is especially known in California and other warm parts of the Americas, where it does great damage to vineyards. An infected vine cannot yet be cured.

Pierce's disease is counted among vine diseases. It is fought by controlling leafhoppers, removing sick vines and choosing resistant varieties. The bacterium has also appeared in some areas of Europe, and is monitored. It is dangerous only for plants; it is harmless to humans, and wine from healthy grapes is safe.