Xylella fastidiosa disease could cost olive oil producing regions billions of euros over the next 50 years, according to new research. Scientists from the University of Wageningen have developed an economic model to predict the potential future impact of olive tree blight Xylella fastidiosa ​in Southern Europe.

According to their findings, Italy, Greece and Spain are expected to lose “billions of euros”. In a best-case scenario, whereby replanting with resistant varieties is feasible, Italy could lose between €0,6 billion and €1,6 billion. In a worst-case scenario, in which production ceases after orchards die off, the impact could reach €5,2 billion.

In Greece, a best-case scenario was estimated at a loss of €0,09 billion, and worst-case €1,94 billion. In Spain, a best-case scenario could see the industry lose €0,39 billion. A worst-case scenario, however, could see producers lose up to €16,86 billion.

Dangerous plant pathogenic bacteria

Notorious olive blight Xylella fastidiosa ​is regarded one of the most dangerous plant pathogenic bacteria worldwide.

The University of Wageningen’s study focused on a subspecies of the bacteria known as Xylella fastidiosa pauca​ (Xfp​).

The bacterium is naturally transmitted by insect vectors, which feed on the xylem of host plants. Symptoms include leaf loss, dieback, and delayed growth. When the bacterium sufficiently obstructs the xylem, and water is unable to flow through the host, trees eventually die.

Xfp ​was first detected in olive trees in Europe in 2013. While efforts were made to control vectors and fell trees, the researchers believe the size of the area currently affected, and the presence of symptomless but infectious host plants, is “likely to hinder any attempts of disease eradication”.

Currently, Xfp ​is present in Portugal, Italy, France, and Spain. This latest study focused on the latter three, however, as these countries account for around 95% of European olive oil production.

European olive oil industry

Even under slow disease spread, and the ability to replant infected trees with Xfp​-resistant replacements, the researchers expect the disease to have a detrimental impact on the olive oil industry.

Moving forward, the scientists stressed the necessity of ongoing research into cultivar resistance traits, alongside vector control and inoculum suppression, to limit the disease’s spread.

According to IRI data, the European olive oil market is worth €3 billion, with extra virgin oil accounting for €1,2 billion and standard olive oil around €0,75 billion.

Europe is the leading producer, consumer and exporter of olive oil, producing roughly 67% of the world’s total. Approximately four million hectares – predominantly in Southern Europe – are dedicated to the cultivation of olive trees.

Concerning consumption, Italy and Spain have the greatest annual intake, at around 500 000 tons each. Greece, meanwhile, has the largest European Union (EU) consumption per capita, at around 12kg per person per year.

In terms of trade, the EU accounts for roughly 65% of world exports, with the main destinations for EU olive oil being the United States, Brazil and Japan. – Food Navigator