Friday, January 9, 2015

Europe’s olive trees threatened by spread of deadly bacteria

Arthur Neslen in the Guardian (UK): First it was Europe’s ash trees under threat from disease. Now it’s the continent’s olives in the firing line. A killer pathogen that has established itself in southern Italy is now “very likely” to spread, posing a major risk to European olive trees, according to an assessment by the European Food Safety Authority (Efsa).

Xylella fastidiosa, also known as olive leaf scorch, has taken hold in the Apulia region at the southernmost tip of Italy, where several thousand hectares of olive plantations are now affected. The bacterium kills infected plants by preventing water movement in trees, causing leaves to turn yellow and brown before falling off, their branches following soon after.

Its “establishment and spread in the EU is very likely,” the scientists’ report says. “The consequences are considered to be major because yield losses and other damage would be high and require costly control measures.”

The disease’s impact comes on top of a particularly bad year for Spanish and Italian olive growers in 2014 due to pests and the weather, with harvests in Italy down 40-50%. Spain and Italy account for 70% of Europe’s olive output, leading to warnings that olive oil prices will rise. “The outbreak in Apulia is very severe,” said Giuseppe Stancanelli, one of the report’s advisors. “The bacteria is deadly and many plants in Lecce province are dying because of it.”

Xylella is an exotic pathogen common in the Americas and the Middle East, which is thought to have been brought to Europe by infected insects carried with plant commodities, or travelling as stowaways....

An olive tree, shot by Anna Anichkova, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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