Italian olive trees are withering from this deadly bacteria

GWEN IFILL:

Next: Olive oil is a staple in many of America's kitchens, and much of it is produced in Italy. But a mysterious infection is now threatening that industry and a way of life.

Jeffrey Brown recently traveled to the olive groves of Southern Italy.

JEFFREY BROWN:

It's the heel of Italy's boot. The Salento region may be less known than the country's more famous tourist areas. But it boasts beautiful port towns and idyllic country roads lined with farms, vineyards and, most of all, its renowned olive groves, some thousands of years old.

GIOVANNI MELCARNE, Oliver Grower (through interpreter):

For us, these are not only trees that produce olive oil, but they are the Salento landscape itself. Without these trees, the Salento will no longer exist.

JEFFREY BROWN:

A deadly bacteria dubbed an olive Ebola has infected some million trees so far, about 10 percent of the trees in the larger Puglia province. Some of those olive groves have been in families for generations.

That's the case for Giovanni Melcarne, a grower who believes 500 of his 5,000 trees are now infected.

But you're fairly certain that all of this will be lost.

GIOVANNI MELCARNE (through interpreter):

By what we have seen so far in the past few months, yes.

JEFFREY BROWN:

The bacteria is Xylella fastidiosa, and for years has been found in a variety of plants in Brazil and California. It is commonly known as Pierce's disease.

But this strain was discovered two years ago in Italy by Donato Boscia, a virologist at the National Research Council in Bari, while he was visiting his father-in-law's farm.

DONATO BOSCIA, Virologist:

My father in law said, "Donato, please, tomorrow, we can go in the field. I want to show you some abnormal — of the olive trees." And I went there and I was shocked.

JEFFREY BROWN:

The first signs of infection are dried-out leaves, known as leaf scorching.

Eventually, the whole tree withers. It's thought to have come to Italy via Costa Rica, hitching a ride on a decorative coffee plant. And it's spread by insects feeding on tree tissue. Boscia's team is monitoring that spread by confirming samples, studying its carriers, and testing the live bacteria on various olive subspecies to see which might be resistant.

DONATO BOSCIA:

We are sure that the only tool that we have at the moment available to try to prevent the appearance of this disease, of this quick decline of olive is try to prevent the arrival of the bacteria.

JEFFREY BROWN:

Italians take their food very seriously, and on nearly every table is a bottle of good olive oil. On average, Italy trails only Spain in oil production, responsible for 15 percent of the world's virgin olive oil and half of U.S. imports in an industry that pulls in more than $2 billion a year to the country.

Its popularity has only grown, as it's been touted for a range of health benefits, including reducing the risk of heart disease. With so much at stake, for Italy and the rest of Europe, the European Union earlier this year established a buffer zone to contain the bacteria to one province in the south, a controversial move that left many growers angry.

GIOVANNI MELCARNE (through interpreter):

We are very dissatisfied. The E.U. is only interested in blocking the advance of the bacteria to the north. This area, the area of the breakout, has been left to its fate.

JEFFREY BROWN:

The measure required the cutting down of infected trees and even seemingly healthy ones nearby.

GIUSEPPE SILLETTI, Regional Director, Italian Forestry (through interpreter):

My job would be a lot easier if not for all the misunderstanding. Every group has different thoughts on how to tackle the problem.

JEFFREY BROWN:

Giuseppe Silletti, regional director of Italy's Forestry Service, is the man tasked with implementing that plan for the Italian government and E.U. But he says he's not getting the help he needs from farmers.

GIUSEPPE SILLETTI (through interpreter):

I have news that the owners do everything they can to hide the disease. If they have a tree with symptoms, they prune the plants, so they look healthy. This is very bad, because it prevents us from being able to identify how much the disease is spreading.

JEFFREY BROWN:

In fact, many farmers and activists are skeptical of both the government response and the scientific research on the bacteria.

Virologist Donato Boscia was even accused of introducing the bacteria into Italy.

DONATO BOSCIA:

Saying to these people, sorry, but we are, how to say, a cancer, like that, so something that you can not cure, that your time is limited, there are — no therapy, is something that is difficult to accept.

JEFFREY BROWN:

Some, like olive grower Roberto Polo, believe a variety of factors, including pesticides, are to blame.

ROBERTO POLO, Olive Grower (through interpreter):

I believe that it is not only the bacteria to blame for the rapid drying out of the olive trees, but a combination of causes which have compromised the immune system of the trees. In practice, we have seen a reduction in the ability of the trees to defend themselves from external attacks of any kind.

ROBERTO ZILETTI, Business Owner:

It's a matter of time. It will come.

JEFFREY BROWN:

Polo's neighbor, Roberto Ziletti, owns the Antica Masseria del Fano, an old farm that's been converted into a bed and breakfast with its own prize-winning olive oil production.

ROBERTO ZILETTI:

Historically, there are people that believe that these things always happen, and it will — as it arrives, it will go away, alone.

JEFFREY BROWN:

Just naturally.

ROBERTO ZILETTI:

Naturally.

JEFFREY BROWN:

Yes.

ROBERTO ZILETTI:

I don't know if this is true. Probably, it's true, but the matter is that these days the problem is very, very big.

JEFFREY BROWN:

The government has been attempting to enlist more cooperation from farmers by paying them to cut down their own infected trees. That plan was dealt a blow last month when a regional Italian court temporarily halted the removal of outwardly healthy trees in the infected zone, until the bacteria could be proven as the cause of the disease.

Researcher Boscia responds this way:

DONATO BOSCIA:

We do not have the proof that the bacterium alone can cause the disease, but the disease appear only when the bacterium arrive there.

JEFFREY BROWN:

Also unknown is the incubation period, meaning many more trees could be infected and not yet symptomatic.

GIOVANNI MELCARNE (through interpreter):

In Italy, we have 100 different opinions. But what is certain is that these plants are dying, that these plants are drying, and we don't know what the future will be. And we don't even know that there's a solution to this situation.

JEFFREY BROWN:

And there are already signs the bacteria has spread farther north, even to France and Corsica, though not yet infecting olive trees, suggesting this problem isn't going anywhere anytime soon.

From the boot of Southern Italy, I'm Jeffrey Brown for the PBS NewsHour.