The olive quick decline syndrome in south-east Italy: a threatening phytosanitary emergency

The olive quick decline syndrome (OQDS) is a disease that appeared suddenly a few years ago in the province of Lecce (Salento peninsula, southeastern Italy). Among the factors that may be involved in its aetiology, the most relevant is Xylella fastidiosa, a quarantine pathogen of American origin, whose presence in Italy represents its first confirmed record in the European Union. X. fastidiosa is a Gram-negative bacterium that invades the xylem of a wide range of hosts, from which it is acquired by xylem-feeding insect vectors and transferred to other plants. The bacterium multiplies within the plant vessels and occludes them, thus impairing water uptake. Besides olive, the Salentian strain of X. fastidiosa infects in nature a number of woody (almond, cherry) and shrubby (oleander, broom, Acacia saligna, Polygala myrtifolia, Westringia fruticosa, Rosmarinus officinalis, Rhamnus elaternus, Myrtus communis) hosts, with no evidence for grapevines or citrus being hosts. The bacterium was isolated in culture and identified as a genotype of X. fastidiosa subsp. pauca, molecularly identical to an isolate from Costa Rica. Philaenus spumarius (meadow spittlebug), a froghopper quite common in the Salento area where it thrives on olive, was identified as the main vector. Disease eradication and sanitation of infected olives are unfeasible. However, strategies are being enacted for restraining the spread of pathogen and vector(s) within the boundaries of the currently infected zone.

[1]  F. Palmisano,et al.  NEW HOSTS OF XYLELLA FASTIDIOSA STRAIN CoDiRO IN APULIA , 2014 .

[2]  S. Lindow,et al.  Living in two worlds: the plant and insect lifestyles of Xylella fastidiosa. , 2008, Annual review of phytopathology.

[3]  F. Porcelli,et al.  Infectivity and Transmission of Xylella fastidiosa by Philaenus spumarius (Hemiptera: Aphrophoridae) in Apulia, Italy , 2014, Journal of economic entomology.

[4]  M. Forim,et al.  N-Acetylcysteine in Agriculture, a Novel Use for an Old Molecule: Focus on Controlling the Plant–Pathogen Xylella fastidiosa , 2013, PloS one.

[5]  A. Italiano,et al.  Draft Genome Sequence of the Xylella fastidiosa CoDiRO Strain , 2015, Genome Announcements.

[6]  A. Obradović,et al.  XYLELLA FASTIDIOSA: ITS BIOLOGY, DIAGNOSIS, CONTROL AND RISKS , 2010 .

[7]  R. Haelterman,et al.  FIRST PRESUMPTIVE DIAGNOSIS OF XYLELLA FASTIDIOSA CAUSING OLIVE SCORCH IN ARGENTINA , 2015 .

[8]  D. Hopkins,et al.  Fastidious xylem-limited bacterial plant pathogens. , 1996, Annual review of phytopathology.

[9]  M. Achtman,et al.  Multilocus sequence typing: a portable approach to the identification of clones within populations of pathogenic microorganisms. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[10]  D. Makowski,et al.  Scientific Opinion on the risk to plant health posed by Xylella fastidiosa in the EU territory, with the identification and evaluation of risk reduction options , 2015 .

[11]  J. Wells,et al.  Xylella fastidiosa gen. nov., sp. nov.: Gram-negative, xylem-limited, fastidious plant bacteria related to Xanthomonas spp. , 1987 .

[12]  F. Porcelli,et al.  Survey of the Auchenorrhyncha in the Salento peninsula in search of putative vectors of Xylella fastidiosa strain CoDiRO , 2014 .

[13]  D. Stenger,et al.  Evaluation of Olive as a Host of Xylella fastidiosa and Associated Sharpshooter Vectors. , 2014, Plant disease.

[14]  Karyn L. Newman,et al.  Production of Xylella fastidiosa diffusible signal factor in transgenic grape causes pathogen confusion and reduction in severity of Pierce's disease. , 2014, Molecular plant-microbe interactions : MPMI.

[15]  R. Redak,et al.  The biology of xylem fluid-feeding insect vectors of Xylella fastidiosa and their relation to disease epidemiology. , 2004, Annual review of entomology.

[16]  Donald L. Hopkins,et al.  Xylella Fastidiosa: Xylem-Limited Bacterial Pathogen of Plants , 1989 .

[17]  A. Purcell.  Paradigms: examples from the bacterium Xylella fastidiosa. , 2013, Annual review of phytopathology.

[18]  Oepp Eppo.  EPPO data sheets on quarantine pests : tomato spotted wilt tospovirus , 1999 .

[19]  K. Djelouah,et al.  DETECTION OF XYLELLA FASTIDIOSA IN OLIVE TREES BY MOLECULAR AND SEROLOGICAL METHODS , 2014 .

[20]  Franco Valentini,et al.  Direct tissue blot immunoassay for detection of Xylella fastidiosa in olive trees , 2014 .

[21]  F. Nigro,et al.  FUNGAL SPECIES ASSOCIATED WITH A SEVERE DECLINE OF OLIVE IN SOUTHERN ITALY , 2013 .

[22]  G. Martelli,et al.  First report of almond leaf scorch in Turkey. , 2005 .

[23]  G. P. Martelli,et al.  IDENTIFICATION OF DNA SEQUENCES RELATED TO XYLELLA FASTIDIOSA IN OLEANDER, ALMOND AND OLIVE TREES EXHIBITING LEAF SCORCH SYMPTOMS IN APULIA (SOUTHERN ITALY) , 2013 .

[24]  F. Porcelli,et al.  ISOLATION OF A XYLELLA FASTIDIOSA STRAIN INFECTING OLIVE AND OLEANDER IN APULIA, ITALY , 2014 .

[25]  G. Martelli,et al.  Survey for the presence of Xylella fastidiosa subsp. pauca (strain CoDiRo) in some forestry and ornamental species in the Salento peninsula. , 2015 .

[26]  A. Purcell,et al.  XYLELLA FASTIDIOSA , A REGIONAL PROBLEM OR GLOBAL THREAT? , 1997 .

[27]  L. Nunney,et al.  The Complex Biogeography of the Plant Pathogen Xylella fastidiosa: Genetic Evidence of Introductions and Subspecific Introgression in Central America , 2014, PloS one.