In two opinions released on Wednesday (15 May), the EU Food Safety Agency confirmed that there is still no known way to eradicate the xylella fastidiosa from a sick olive tree. Control measures can contain the disease, but they have to be applied, EFSA’s director told EURACTIV.
EFSA’s Plant Health Panel (PLH) updated the agency’s assessment of the notorious olive trees killer, publishing two opinions on the risks to plant health and on the effectiveness of in planta control measures.
The xylella bacteria mainly affect olive trees, with infected plants displaying scorched leaves, dried branches and rapid deterioration, which in the most severe cases can lead to the death of the tree.
First detected in Italy in 2013, xylella fastidiosa started to spread rapidly across Southern Europe. It reached France, where it was first identified in Corsica and Provence-Alpes-Côte d’Azur in 2015, as well as Spain, where the area currently affected by the disease amounts to more than 134.000 hectares since October 2016.
At the start of 2019, a new xylella outbreak was reported again in Italy, in the Monte Argentario in Tuscany.
Computer simulations developed by EFSA’s experts showed that most of the EU territory is potentially suitable for the establishment of xylella, although southern Europe is most at risk.
Some variations of the bacteria, like xylella fastidiosa subspecies multiplex, have greater potential to establish in northern Europe than other subspecies, the virtual modelling showed.
However, the computer simulations also illustrated the effectiveness of the emergency phytosanitary control measures, if put in place correctly and applied in time.
It is possible to limit the spread or even locally eradicate the pest with control measures like the timely removal of plants in the infected areas or efficient vector control.
EURACTIV talked about the outcomes provided by the experts with EFSA’s Executive Director Bernhard Url: “The opinions we published today are a confirmation of the science we published over the last five years,” he said.
“Although there is no cure, the disease can be contained and locally can even be eradicated with strict and fast measures,” he added.
In this regard, he highlighted that one of the main outcomes of the two scientific studies is that the different kinds of control measures are effective.
“But they have to be applied,” he said, “and the faster you are with detecting and implementing control measures, the more the disease can be contained.”
A similar remark was made by the Health Commissioner Vytenis Andriukaitis at last November’s Agrifish Council, when he said Europe was facing the consequences of the failure to identify the xylella problem at an early stage.
The Commissioner added that there is now a responsibility both for the EU and the member states to learn from the mistake and avoid repeating it in the future.
According to Bernard Url, computer simulations have shown that xylella could manifest itself in the entire EU, but Southern Europe is obviously more exposed to the bacteria.
“It is now important for the risk managers, not only in Italy, to rethink and reinforce their control measures,” he concluded.
“A wealth of new information has become available since our last opinion was published in 2015 and our understanding of this dangerous plant pest is advancing all the time,” said
Stephen Parnel, the Chair of the PLH Panel on xylella, said a “wealth of new information has become available since our last opinion was published in 2015 and our understanding of this dangerous plant pest is advancing all the time”.
But it is vital that we continue to invest in research that can help us to not only control outbreaks but anticipate them, he added.
[Edited by Zoran Radosavljevic]