In October 2013 Xylella fastidiosa was detected in olive trees in Lecce province in Apulia, Italy. It was the first outbreak of X. fastidiosa under field conditions to be reported in the European Union. In November of the same year EFSA provided the European Commission with urgent scientific advice and technical assistance on X. fastidiosa.
Following publication of EFSA’s advice, in February 2014 the European Commission put in place emergency measures to combat the spread and further introduction of the organism into the EU. These measures were further strengthened in May and October 2015.
In January 2015 EFSA published a full pest risk assessment and evaluation of risk reduction options for X. fastidiosa in the EU. The scientific opinion included a list of host plants and European vectors of the bacterium. In March 2015, EFSA published a report categorising plants for planting, excluding seeds, according to the risk of introduction of X. fastidiosa.
In April EFSA responded to a claim by an Italian non-governmental organisation that a series of fungi – rather than X. fastidiosa – are the main causal agents of olive decline in Apulia. EFSA concluded that there was no scientific evidence that tracheomycotic fungi are the primary cause of olive die-back in Apulia.
A Scientific Opinion published by EFSA in September indicated that hot water treatment – whereby dormant plants and plant parts are submerged for 45 minutes in water heated to 50C – is a reliable method for controlling X. fastidiosa in dormant grapevine planting material.
In November 2015, more than 100 scientists from around the world attended a workshop hosted by EFSA to identify the main knowledge gaps and discuss research priorities for X. fastidiosa. In the same month, EFSA evaluated the results of ongoing studies and experiments carried out in Apulia, concluding that grapevine cannot be ruled out as a potential host of X. fastidiosa.
In February 2016 EFSA’s database of host plants was updated to include 44 new species. The majority of the new species (70%) were identified in southern Italy (Apulia), Corsica and southern France (Provence-Alpes-Côte d'Azur region).