OLIVE quick decline syndrome, which is affecting trees across Europe, could cost billions over the next 50 years, according to a new study.

Spread by insects, the bacterial plant pathogen Xylella fastidiosa causes the death of infected olive trees. To determine the economic impact of the bacterial strain, lead author Kevin Schneider from Wageningen University in the Netherlands and colleagues developed a bioeconomic model of the pathogen's future spread and impact.

Factoring in economics of different cultivation systems in Greece, Italy, and Spain, the authors modelled economic losses under a scenario in which all growing ceased due to tree death, compared with a scenario in which replanting with resistant varieties occurred.

The authors report that in Italy, for example, cessation of production after orchard die-off would result in an economic impact of up to 5.2 billion euros, and replanting orchards with resistant varieties can lower the impact to around 1.6 billion euros.

The authors modelled a radial spread based on the distribution of olive orchards from land cover data and found that slowing the spread with measures such as removal of infected plants could save up to 1.3 billion euros. The findings underscore the potential economic impacts of a major bacterial pathogen of olive trees, according to the authors.

Dr Maria Saponari, from the CNR Institute for Sustainable Plant Protection in Italy, told the BBC: "The damage to the olives also causes a depreciation of the value of the land, and to the touristic attractiveness of this region.

"It's had a severe impact on the local economy and jobs connected with agriculture."

The study has been published in the journal Proceedings of the National Academy of Sciences (PNAS) and is available here.