Xylella fastidiosa is a disease that threatens olive crops in a number of European countries and in our country. This is a very dangerous bacterium that destroys olive trees and spreads like wildfire, especially in Spain, France and Portugal.

The disease causes rapid drying of trees and is one of the biggest common threats to global agriculture as well as to the ancient landscapes in which generations of southern European villages grew up.

Blanca Landa was recently named head of an international program aimed at stopping the spread of a microbe that, when it enters a new region, turns it into a kind of “Chernobyl plant”.

Suffocation in olive trees

The Xylella bacterium is native to the Americas and mainly causes asphyxiation in tree branches.

Insects of the Cicadellidae family, known as Cicadelids, are responsible for carrying the microbe from one plant to another. The bacterium arrived in southern Italy in 2008, traveling through coffee plants from Costa Rica. By the time scientists spotted it in 2013, it was already too late. In just a few years, the bacterium destroyed more than six million trees.

“I remember old farmers crying while hugging their olive trees,” says Blanca Landa, emphasizing that in order for an olive grower to get rid of bacteria, he must prune the specific tree, as well as trees within a 50-metre radius.

“Xylella is capable of infecting up to 600 different plant species. It “travels” around the world and affects mainly olive trees, vines, almond trees, citrus and stone fruit trees.

So far, the microbe is “winning the war,” Landa said.

“You have to learn to live with the bacteria and minimize the damage. What manufacturers want is to stop pesticides and the problem will just disappear, it will never happen,” he says.

Teaching dogs to detect bacteria

The international project, which received funding of 7 million euros from the European Union, is mainly focused on developing methods for detecting the microbe.

“The best way to fight a bacterium is to keep it away,” Landa says, pointing out that three Italian organizations are training dogs to detect bacteria in infected plants and trees.

On the other hand, Spanish researcher Pablo Zakro and his team at the University of Melbourne are improving a system with cameras that will detect trees affected by the bacterium.

Another biologist on the team, Manuel Anguita, undertook to study the more than 2,000 species of “good” bacteria that live inside olives.

“Our goal is to develop a cocktail of beneficial bacteria that can be injected into small trees and prevent the spread of the killer microbe,” he says.

The orange has the taste of life, the olive has the taste of time.

Finally, Landa points out that the preservation of olive trees also protects an important part of history and culture.

“One of the oldest olive groves in the world, known as Farga del Arion, is located in the municipality of Uldecona in Tarragona, Spain. It was planted by Roman farmers in AD 314, during the time of Emperor Constantine, scientifically dated to be over 1700 years old. As you understand, the cost is not only financial, but also historical. As the poet Miguel Hernandez said: “The orange tree has the taste of life, and the olive tree the taste of time.”

Source: El Pais