Bacteria behind lethal vine disease found on French soil

Bacteria known to cause Pierce's Disease that has blighted California vineyards for years has been found in France for the first time.

The Xylella fastidiosa bacteria has been discovered on the island of Corsica, just over 18 months after its first recorded appearance in Europe, in olive groves in Italy.

News of its spread to Corsica prompted a fierce reaction from Europe’s plant protection organisation (EPPO), which said this week that ‘eradication measures have been immediately implemented’.

It is a potentially worrying development for wine producers – and wine drinkers.

Xylella fastidiosa is the source of Pierce’s Disease, a lethal vine disease that has caused serious damage in California’s vineyards, where it costs $104m annually. European Union officials said the bacteria ‘represents a major risk to EU territory’.

But, French government vine expert Jacques Grosman told the Vitisphere.com website that there was currently ‘a low risk of contamination in France’.

• See also: Deadly vine diseases now top priority for French winemakers

In California, xylella fastidiosa is transferred by the blue-green sharpshooter. In Europe, all sap-feeding insects are considered to be potential vectors. It is not know how the bacteria arrived in Italy, where it has killed swathes of olive trees in Puglia.

Pierce’s Disease was discovered in 1892 by Newton B. Pierce (1856–1916) on grapes in California near Anaheim. There is no cure and there are no resistant Vitis Vinifera grape varieties. Chardonnay and Pinot Noir are especially sensitive while Riesling, Sylvaner and Chenin are more resistant.

Infected vines appear water stressed, according to researchers at UC Davis in California. ‘Leaves become red or yellow in mid-summer, berries shrivel [and] dried leaves fall,’ its guidance says.