A disease that ravaged California’s vines in the early 2000s has been found for the first time in two French olive trees. No vine infections have yet been seen in France or Europe, but a September 6th statement from the French Agriculture Ministry described the Xylella fastidiosa bacteria as potentially deadly for a range of plants. Currently, no cure exists.
The statement said the two infected trees were found in the Provencal towns of Antibes and Menton. Both are being uprooted to prevent further spread.
In Europe the bacteria, which kills by choking a plant’s hydration system, is known for the damage it has done to Italy’s olive groves. Cases have also been found in Spanish olive trees and Portuguese lavender plants.
Both the French government and the European Commission, which calls it “one of the most dangerous plant bacteria worldwide” remain on high alert for infections. In Australia – which remains fastidiosa free – one vineyard organisation describes the bacteria as the “number one unwanted pest”.
While several subspecies of Xylella exist, the most common are fastidiosa, pauca, multiplex and sandyi. In California infections are known as Pierce’s Disease or California Vine Disease.
It’s believed one reason Europe’s vines remain uninfected to date is the absence of a suitable carrier insect. In California this job is often done by the glassy winged sharpshooter. Eradication of carriers is one method used to control the disease.
Jean-Jacques Balikian who follows the bacteria’s developments and is the director of the Sainte Victoire Vine Association in Côtes-De-Provence, said the absence of the disease in French vineyards would therefore depend on two factors. The continued carrier absence is one. “The other thing is that we apparently don’t have a suitable climate for the carrier,” he said.
But that could change. The global movement of plants around the world could bring potential carriers and changing climate patterns might make conditions more hospitable, he said.
Given the unknowns, Balikian called for more research. “We need more research into why we don’t have any vine infections, even though we have the bacteria.”