Plant plague at Portugal’s door: 73 tree species at risk

A new ‘plant plague’ – particularly attacking trees and vines – is at Portugal’s ‘door’, having cut a deadly swathe through southern Europe.

There is no cure for Xylella fastidiosa, say reports – and in spite of a debate in Évora recently, bringing together an impressive number of agricultural experts, Portugal doesn’t appear to have any idea how to deal with the threat of its imminent arrival.

Says tabloid Correio da Manhã in a special feature on what it dubs “the silent threat”, some experts recommend the cutting down of all trees within a 100 metre radius at the first sign of the disease.

Others consider this far too radical, and favour instead “living with the disease” – which attacks vines, as much as it can wipe out fruit orchards and olive and almond groves.

“We could be facing an economic drama”, warns CM – explaining that the blight is a bacteria disseminated by insects.

In Spain and Italy it has already caused havoc for olive oil producers, after arriving purportedly via diseased almond trees imported from California.

2013 seems to be the date that Xylella fastidiosa first showed itself to be active in southern Europe, and since then it has been all downhill.

The bacteria apparently “multiplies in layers, producing a kind of glue”, explains CM.

With its progression, plant cells become blocked, “prohibiting nutrients travelling up through the roots to leaves”.

Brown marks appear on affected areas, but even so, detecting the disease with the naked eye at the early stages is “very difficult”.

CM’s exposé today suggests that Portugal’s signature trees and plants are likely victims: medronho, almond, cork oaks and vines.

Our climate works against us: the winters are simply not harsh enough to kill the bacteria, and it flourishes in hot, dry conditions.

And while investigation is underway to try and find a cure, it may come too late. Says CM, “if the country is worried, producers are terrified” as the disease will “condemn many to bankruptcy”.

“What producer will have the courage to say they have it on their plantation”, queried Francisco Pavão of the Confederation of Portuguese Farmers taking part in the Évora debate, “if the consequence will be to cull all trees within a 100 metre radius and have nothing more to do with his land?”

Pavão is recommending the formation of a special Xylella group to try and find answers.

He told the seminar that just in the area of Trás-os-Montes there are 37,000 businesses – “the majority producing olives and almonds”, two of the commonly susceptible species.

The consensus emerging is that scientific research is the only way forwards, but even so, Xylella fastidiosa’s inevitable arrival heralds “major economic impacts”.

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