“In early 2016, Giovanni Melcarne, an agronomist and the owner of an extra virgin olive oil farm in Gagliano del Capo, walked through the southern Italian countryside of Puglia. He was with a fellow olive-oil farmer who had called and told him there was something he had to see.
The two approached a centuries-old olive tree growing at the edge of the street along a traditional stone wall. All around, the old olive trees that covered the red clay were either dead or in an advanced state of decay, filling the landscape with an unnatural greyness. Melcarne was not surprised: At least 2 million olive trees in Puglia looked this way, including many of his own.
The cause of the blight was Xylella fastidiosa, a bacteria that researchers believe arrived around 2010 from Latin America, possibly from Costa Rica on an imported ornamental plant. Today, Xylella has infected at least one-third of the 60 million olive trees in Puglia, which produces 12 percent of the world’s olive oil. The bacteria leaves no chance of survival: Once a plant is infected, it’s doomed to die in a handful of years. Today, Xylella is spreading fast across Puglia, crossing into other Italian regions and Mediterranean countries, and upending the production of olives and olive oil, the symbols of the Mediterranean.
When the two reached the tree, the olive farmer pointed at a live, green bough on the otherwise dead trunk.
“The man told me that his father had grafted the tree with a Barese olive variety, which is good for eating,” Melcarne says. Grafting is common practice in the area: People take a twig of a different variety and insert it on the trunk of an older tree, where it will grow and bear the kind of olives of the tree it came from. Melcarne immediately suspected that the grafted branch was resistant to Xylella. It seemed to be keeping the olive tree alive.
“And then I thought, ‘Could it be that grafts could save the oldest and grandest olive trees’?” Melcarne says.
At the time, efforts to contain the Xylella blight were going poorly: Italian media and politics was dominated by vicious fights, accusations, and conspiracy theories that prevented a coordinated response. But seeing that bit of green, Melcarne felt hopeful. The agronomist was already exploring ways to fight the disease with a team of scientists, and that visit showed that there might be some hope against the olive-tree apocalypse.
“If today we don’t try to save at least some of the monumental olive trees,” Melcarne asks, “what identity will be left to this region?”
Whether you are in New York, London, or Melbourne, chances are good that the extra virgin olive oil you use to dress your salad, finish a fresh mozzarella, or sear a sea bass comes from Puglia. It is either explicitly labeled as such or, in many cases, disguised under the branding of other estates that didn’t quite yield the harvest they were expecting.
In Puglia, olive trees are everywhere. They have populated these lands since 1,000 BC, when the ancient Greeks brought them. Some trees still growing today saw ancient Romans passing by or welcomed Emperor Frederik II on his way to the Sixth Crusade, while many more were already old when Christopher Columbus stumbled upon the Americas. The trees have always been present in their corrugated fairy shapes, and they are an inherent part of the local culture. Each family owns a few olive trees and treats them like family, like immortal grandparents. Pugliesi have taken their presence for granted for a long time, but Xylella is now crushing that timeless, idyllic reality.
Xylella fastidiosa is carried by a sap-feeding insect, a spittlebug called Philaenus spumarius. When the insect bites an infected leaf, it involuntarily takes the bacteria on its saliva, giving Xylella a free ride to the next plant it feeds on. Through the bite, the bacteria enter the xylem––the plants’ vascular tissue, where water and nutrients flow––traveling countercurrent towards the roots. As the bacteria reproduce, they create a gel that clogs the channels, preventing water and nutrients from passing through. Once the plant is infected, it slowly starts dying.
The disease’s symptoms first appeared around 2010, but Italians didn’t know what was killing their trees. In 2013, scientists realized that it was Xylella. It was the first detection in Europe, and the European Union and Italian government immediately pushed for containment measures that implied the eradication of the infected trees. Speed was crucial: Stopping the spread would only get harder as it dispersed across Italy.But many Pugliesi could not believe that a bacteria could kill these eternal trees. So thousands of people campaigned to stop the uprootings. Farmers chained themselves to infected trees, stopped railways, protested in city centers, and got full support from TV personalities, singers, and politicians, including Michele Emiliano, the region’s governor.
Much like the millions of people who would later resist pandemic lockdowns or call Covid-19 a hoax, the protesters believed that what was happening was part of a conspiracy. Some believed it was Monsanto’s fault and that the agrochemical company wanted to sell seeds for immune, genetically modified olive trees to farmers. Others said it was entrepreneurs and the Mafia, who wanted to build indiscriminately where the trees stood. A few more blamed chemtrails. The enraged public opinion led by an anti-science movement got so much momentum that in December 2015, government prosecutors from the city of Lecce started investigating the scientists studying the disease, blaming them for having brought it to Puglia. (After four years of investigations, all charges were dropped.)
“I do not expect to be thanked, but being pilloried by the media for having done my work with passion is a paradox,” says Donato Boscia, a plant pathologist and head researcher for Xylella at the National Research Council of Italy (CNR).
While conspiracies flourished, the disease advanced north at a speed of 30 km (18.6 miles) a year. Xylella is present in several countries worldwide, including the U.S., where it has been known for more than a century for attacking grapevines. But before arriving in Puglia, Xylella had never been detected on olive trees before.
“We could not wait for somebody else to deal with it,” says Pierfederico La Notte, an agronomist and researcher working on Xylella at CNR with Donato Boscia. While they studied how Xylella impacted the olive trees, Boscia and La Notte met with Giovanni Melcarne, the olive oil producer from Gagliano del Capo. Melcarne had noticed that in Salento, the lower tip of Puglia, certain olive trees were still alive between an ocean of death. It was 2016, and Melcarne brought the scientists to Gallipoli to check the green and thriving graft his fellow farmer had shown him, which later turned out to be Leccino––one of the only two olive varieties known to be resistant to the bacteria.
“That plant lightened up lots of lightbulbs,” La Notte says. Grafting, a technique as old as agriculture, seemed to show promise, just like it did a century ago when it saved European grapevines from Phylloxera, a tiny aphid that nearly destroyed the continent’s wine industry. If a resistant variety of olives could be grafted on the millenary trunks, the plant appeared to have a chance of survival.
In April 2016, while local politicians were delaying scientific research by withholding funding, Melcarne invested 130,000 euros––around $156,000, his lifetime savings––to graft 14 hectares of his olive trees. His family had been in the olive business since the 1500s, so Melcarne took the enormous financial risk not only to save his company, but to maintain his family’s tradition. He and the CNR researchers wanted to see if the varieties known to be resistant to Xylella––Leccino and Favolosa––could be grafted on older trees, and if other types had some resistance too. Lanotte called on greenhouses, collections, and producers from every corner of the globe, and this international community of scientists and farmers responded by shipping samples of their olive varieties to Puglia. In a short time, they grafted 270 different olive varieties on Melcarne’s fields….”
View the whole story here: https://www.atlasobscura.com/articles/olive-oil-disease-italy