BRUSSELS – From 2012 to 2017, Xylella fastidiosa has seriously damaged approximately 6.5 million olive trees in Puglia. These are some of the new estimates on the impact of the bacterium presented at the second conference on Xylella of the European Food Safety Authority (EFSA), in Ajaccio. From 28 to 30 October in the Corsican capital, over 350 scientists, institutional representatives and trade associations of farmers and nurserymen met to take stock of the fight against new plant pathogens. Mainly Xylella fastidiosa, considered by the EU as public enemy number one. The parasite detected for the first time in 2013 by researchers from the Institute for Sustainable Plant Protection (Ipsp) of the CNR in Bari is the one with the greatest potential impact in economic, social and environmental terms in Europe, as certified by a study by the Joint Research Centre of the Commission. The ‘three-day’ event opened with the final conference of the Ponte research project, the first funded by the EU to also investigate Xylella, which since 2015 has involved 25 organisations from Europe and third countries.

Ponte has made it possible, among other things, to experiment with remote early detection methods and to start testing resistant olive varieties in Puglia. This work will continue with the EU XF-Actors project, whose preliminary results were discussed at the second EFSA conference on 29 and 30 October. On resistant varieties, a simulation by Wageningen University has shown how in the current situation the economic damage for olive growers alone, not counting the oil industry, in Greece, Italy and Spain could reach nine billion euros in 50 years. With replanting, it would go down to 4. On the control of Xylella, encouraging data comes from California, where bacteria capable of substantially reducing infection on vines are being tested.

Researchers from the Ipsp-Cnr of Bari are testing the same type of solutions on olive trees and have presented evidence in Ajaccio that the Apulian strain of the bacterium does not infect vines, laying the foundations for the free marketing of 26 varieties from nurseries in the infected area in Puglia. “Since the first conference two years ago, research has expanded,” says Giuseppe Stancanelli of Efsa, “today we know much more about the vectors that transmit the bacterium, the development of the disease and its control.” Also known and broader is the range of subspecies and strains that have colonized different territories in Europe, with different impacts. In short, if in the years following 2013 Xylella fastidiosa was seen as a unique specimen, now the situation is more complex. Based on new knowledge, in the first months of 2020 the European Commission should present a proposal to EU countries to update the control measures on the pathogen.