Survey for the presence of Xylella fastidiosa subsp. pauca (strain CoDiRO) in some forestry and ornamental species in the Salento Peninsula

Xylella fastidiosa (Xf) is a xylem-inhabiting, vector-transmitted bacterium and the agent of a variety of diseases in a broad range of plant hosts. A destructive Xf outbreak has recently emerged in some olive groves of the province of Lecce (south-eastern Italy), caused by a strain (called CoDiRO from the Italian for Rapid desiccation complex of olive) of Xf subsp. pauca, a pathogen known to infect coffee and citrus in South America. Taking into account that this is the first confirmed record of the presence of Xf in the European Union (EU) territory and fairing its possible spread from the affected site, the EU has issued the Commission Implementing Decision L 45/29- 31 (February 24, 2014), which prohibits the transfer from the province of Lecce of all plant genera and species not listed in the Annex I of the cited Decision. A survey was therefore initiated to verify the health status of a number of ornamental and forestry plants growing mostly in nurseries, but also in public and private gardens, which are or can be naturally exposed to high inoculum pressure. Samples collected from 207 conifers, 105 members of the family Arecaceae, Musaceae and Cycadaceae, and 208 succulent plants (totalling 520) were comparatively examined by serological (DAS-ELISA) and molecular (PCR) methods. None of the tested plant species proved to be infected, providing a strong indication that they may not be susceptible to field infection by the Xf subsp. pauca strain currently present in the province of Lecce.