An Overview of the Emergence of Plant Pathogen ‘Candidatus Liberibacter solanacearum’ in Europe

Abstract

In this paper, a comprehensive overview of the ‘Candidatus Liberibacter solanacearum’ presence in Europe was provided. The analyzed findings revealed that, since the first appearance of this pathogen in Finland and Spain in 2008, it has spread to 13 new European countries. Therefore, ‘Ca. L. solanacearum’ has spread very quickly across the European continent, as evident from the emergence of new host plants within the Apiaceae, Urticaceae, and Polygonaceae families, as well as new haplotypes of this pathogen. Thus far, 5 of the 15 ‘Ca. L. solanacearum’ haplotypes determined across the globe have been confirmed in Europe (haplotypes C, D, E, U, and H). Fully competent ‘Ca. L. solanacearum’ vectors include Bactericera cockerelli, Trioza apicalis, and B. trigonica; however, only T. apicalis and B. trigonica are presently established in Europe and are very important for plants from the Apiaceae family in particular. Moreover, psyllid species such as B. tremblayi, T. urticae, and T. anthrisci have also been confirmed positive for ‘Ca. L. solanacearum’. Constant monitoring of its spread in the field (in both symptomatic and asymptomatic plants), use of sensitive molecular diagnostic techniques, and application of timely management strategies are, therefore, of utmost importance for the control of this destructive pathogen.

First Report of the Association of the Psyllid Vector Bactericera trigonica (Hemiptera: Triozidae) with ‘Candidatus Liberibacter Solanacearum’ in Italy

“…Aside from being responsible for direct damage, such as leaf curling and discoloration and plants' stunted growth, psyllids are also efficient vectors of phytoplasmas and phloem-limited bacteria [1,2]. In this context, several psyllid species belonging to the families Triozidae and Aphalaridae are known to transmit Candidatus Liberibacter solanacearum (Lso) in a persistent and propagative manner [3,4]. Candidatus Liberibacter solanacearum is a Gram-negative bacterium infecting a variety of crops in the families Apiaceae and Solanaceae.…”

“…In addition to yield losses in the field, infection in potato crops results in typical post-harvest symptoms, such as the discoloration of tubers and vascular necrosis, particularly evidenced after frying (disease called "zebra chip") [6]. Lso A and B and their known psyllid vector Bactericera cockerelli (Šulc) are EPPO A1-quarantine pests, and their presence in Europe has not been confirmed yet [4,7].…”