Emergence of Xylella fastidiosa in Balearic Islands, Spain: Current situation

During official surveys in late autumn 2016 in Mallorca Island, Spain, the bacterium was first detected in a garden center near the locality of Manacor. Since then, as of April 24, 2017, a total of 189 positive samples in 11 different host species have been found in different foci in Mallorca (124), Menorca (16) and Ibiza (49) islands. Sequence analysis of the RNA polymerase sigma 70 factor sequence and MLST typing revealed the presence of X. fastidiosa subsp. fastidiosa ST1 and X. fastidiosa subsp. multiplex ST6*(a new ST with the closest being ST6) and ST7 in Mallorca island, X. fastidiosa subsp. multiplex ST6* in Menorca island and X. fastidiosa subsp. pauca ST80 (a new ST) in Ibiza island. Polygala myrtifolia was found to be infected by all subspecies and ST types. Altogether, these results suggest that the emergence of X. fastidiosa in Balearic Islands is likely due to several introduction events of diverse strains from different subspecies. Eradication measures were taken in the garden center according to the Spanish contingency plan and EU legislation. Following the Commission Decision 2015/789/EU if establishing a radius of 10 km to delimit the buffer zone for each infected foci 80%, 50% and 90% of the territory of Mallorca, Menorca and Ibiza islands, respectively, are considered as demarcated areas. Consequently, the best strategy to control the different outbreaks is under study.

Acknowledgment
This work has received funding from the European Union’s Horizon 2020 research and innovation
programme under grant agreement N. 635646 “Pest Organisms Threatening Europe POnTE” and
grant agreement N. 727987 “Xylella fastidiosa Active Containment Through a multidisciplinary-
Oriented Research Strategy XF-ACTORS”.
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