Scientists recently updated the pest survey card that was prepared in the context of the European Food Safety Authority (EFSA) mandate on plant pest surveillance at the request of the European Commission.
The authors say in the introduction to the document that its purpose is to guide the Member States in preparing data and information required for surveys of the causal agent of the zebra chip disease ‘Candidatus Liberibacter solanacearum’ (Lso) and its associated insect vector the psyllid Bactericera cockerelli. These are required to design statistically sound and risk-based pest surveys in line with current international standards.
‘Candidatus Liberibacter solanacearum’ is a regulated non-quarantine pest while the psyllid Bactericera cockerelli, vector of the haplotypes A, B and presumably F, is a Union quarantine pest, also listed as a priority pest. Both organisms are associated with solanaceous host plants. Different haplotypes of Lso have different distribution and hosts. Lso haplotypes A, B and F, and B. cockerelli (able to transmit haplotypes A, B and presumably F) are not known to be present in the EU.
The EFSA scientists say the limiting factor for the spread of the bacterium is the presence of the vector. Import and trade of host plants for planting to and within the EU are the main pathway for introduction and spread of both Lso, especially haplotypes A, B or (presumably) F, and B. cockerelli. Once introduced, local spread of Lso is determined by both the movement of plants and the insect dispersal.
The authors of the EFSA updated document point out that Lso can be detected in leaves and stems of symptomatic plants. Since symptoms are not always easily distinguishable from those associated with phytoplasmas and other biotic and abiotic factors, detection of Lso in plants and insects relies on molecular methods, (real-time polymerase chain reaction (PCR) test). Bactericera cockerelli can be detected effectively by trapping, collecting insects from plants and identified morphologically or molecularly.
Source: EFSA. More information and the full document can be found here.
Authors: European Food Safety Authority (EFSA), Marianne Loiseau, Gritta Schrader, Melanie Camilleri, Alice Delbianco, Makrina Diakaki, Ignazio Graziosi, Sybren Vos
Photo: EFSA – Wiley Online Library – Wiley