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In the Portuguese municipality of Fundão, control services have already detected Xylella fastidiosa on a 20-year-old grapevine on 25 March. This is the first time the bacterium has been found on a grapevine in continental Europe. In 2016, infected vines had already been discovered on the Spanish island of Mallorca.
The pathogen Xylella fastidiosa is the bacterium that is also known for destroying olive trees in southern Apulia. However, the infected vine in Portugal is a different subspecies, Xylella fastidiosa fastidiosa ST1, which is responsible for Pierce's vine disease. It is not identical to the bacterial strain Xylella fastidiosa pauca ST53, which destroys hectares of olive trees in Salento, Italy.
The finding in Portugal is causing great concern among growers and phytopathological services across Europe. Currently, Xylella is one of the top ten quarantine organisms with the highest risk. Pierce's disease, which has been causing severe losses in Californian vineyards for several years, is initially manifested by yellowing of the leaves, which in the course of the disease can lead to the death of entire shoots as well as the vine. It is transmitted via cicadas. Generally, infected plants do not survive longer than one or two years.
Xylella fastidiosa subsp. fastidiosa, like most bacterial diseases, is incurable. The only way to contain its spread is through surveillance, demarcation of areas, eradication by destroying infected plants, and vector insect control.
(ru / source: Mille Vigne)