Andrew Burgess, by email, asks: I was planning to sneak back a few vine cuttings from a trip to France, but on my local radio gardening programme recently, they issued a serious warning not to bring back any plant material from Europe this year, as there is a bad problem with an infection called Xylella.
Does it pose a real threat to vineyards?
Stephen Skelton MW, a UK-based viticulture consultant, replies: Xylella fastidiosa is an incurable disease that affects about 150 mainly hardwood species, the most common being olives, vines, rosemary and oleander.
It was first seen on vines in California in the 1880s and today it is widespread in that state and known as Pierce’s disease.
It is carried from plant to plant by what are called vectors: insects that feed off the plants. In Europe it has done huge damage to olive trees in Italy and Corsica and is responsible for the death of more than a million olive trees in Puglia.
As the climate is warming, Xylella is moving northwards, and it has been found in olive groves and vineyards in Spain and the Balearic Islands.
It has also been found in southern France and Corsica, although only on wild and garden species, and not yet in commercial plantations.
To date, it has been found in the UK on one imported plant. The Department for Environment, Food and Rural Affairs says that there is ‘some concern about the risk of introduction to the UK via infected host plants imported as plants for planting considered to be the most likely pathway for entry’. They also recommend checking country of origin when buying any plants.
This question first appeared in the September 2020 issue of Decanter magazine.