Quantitative Assessment of Consequences of Quarantine Plant Pathogen Introductions: From Crop Losses to Environmental Impact

Pest risk assessments are required to take phytosanitary measures to protect plant health. In the European Union, the Scientific Panel on Plant Health (PLH) of the European Food Safety Authority was established in 2006 as the reference body for risk assessment in the plant health area. Risk assessments address four steps: introduction, establishment, spread and consequences. Until recently, the PLH Panel had made risk assessments requested by the European Commission using qualitative approaches which typically gave risk and associated uncertainty ratings based on ordinal scales. The PLH Panel has now developed guidance on a methodology for quantitative assessment of these four stages. In this chapter, we outline key features of this methodology when applied to assessment of consequences, including both crop and environmental impacts, of the introduction and spread of quarantine plant pathogens into new territories. The methodology is then applied to four case studies Diaporthe vaccinii, Cryphonectria parasitica, Ditylenchus destructor, and the Flavescence dorée phytoplasma – plant pathogens representing a range of taxa, host types and cropping systems.