Development of a pest risk analysis for Phytophthora ramorum for the European Union; the key deliverable from the EU-Funded project RAPRA

Abstract

Pest Risk Analysis (PRA) is an internationally recognized, structured process of determining whether plant pests and pathogens that are absent from a country or area could enter, establish, and cause an economic or environmental risk that is deemed unacceptable. PRA is also used to help identify phytosanitary measures to reduce risks to an acceptable level. United Kingdom (U.K.) PRAs for Phytophthora ramorum have been produced and developed since 2000, starting with the unknown Phytophthora causing sudden oak death in California, United States (U.S.). Other European Union (EU) Member States (MS) have also assessed the risk. As a result of the PRAs, P. ramorum was identified as posing a risk to the environment, private and managed gardens, and woodlands as well as to the ornamental plant trade in the U.K./EU/EPPO region. The prediction that heathland habitats were at risk (based upon host range testing and climatic matching) has now been proven by recent findings of P. ramorum (and P. kernoviae) on bilberry (Vaccinium myrtillus) in heathland in the U.K. Supported by the PRAs, emergency legislation was implemented in the U.K. and subsequently in the EU, allowing action to be taken against P. ramorum whenever it was found. National research projects were commissioned in the U.K. and elsewhere to help fill the gaps in the PRAs; these were inevitable, given the lack of knowledge on this newly identified species.

A major, multi-faceted EU-funded research project ‘RAPRA’ (Risk Analysis for Phytophthora ramorum) commenced in 2004 (http://rapra.csl.gov.uk/). The overall aim was to develop a European-wide PRA for P. ramorum for the 27 MS of the EU; this was to be based on the project’s research findings as well as those emerging in the scientific literature. The project documented the increasing host range and geographical distribution of P. ramorum, including the distribution of mating types; helped determine the potential for sexual recombination; and investigated the potential future host range and aspects of epidemiology related to establishment risk. Refinement of the risk of establishment within the PRA accounted for these findings as well as the results of climatic matching and mapping using several methods. Economic impacts were difficult to assess since currently in the EU P. ramorum affects the commercial plant trade, the natural environment, and historic gardens - with secondary effects on tourism, particularly for southwest England. Commercial forestry is not yet affected, but may be at risk. Recommendations for future management of the risk of entry (for pathways identified from an earlier European and Mediterranean Plant Protection Organization [EPPO] PRA for P. lateralis and by evaluating trade data and existing phytosanitary legislation) were made. Potential measures for managing outbreaks in the EU that were proposed in the PRA were based on a review of existing measures as well as experimental results for disease management. This PRA is the key output from RAPRA and isbeing used in 2009 to review existing EU phytosanitary policy for P. ramorum. This paper summarizes some of the processes for determining the risk of entry, establishment and impacts posed by P. ramorum to the EU, and highlights areas of uncertainty. Full details are available in the PRA at http://rapra.csl.gov.uk/

Parent Publication

• Proceedings of the Sudden Oak Death Fourth Science Symposium

Citation

Sansford, Claire; Inman, Alan; Webber, Joan. 2010. Development of a Pest Risk Analysis for Phytophthora ramorum for the European Union; the Key Deliverable from the EU-Funded Project RAPRA . In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M. 2010. Proceedings of the Sudden Oak Death Fourth Science Symposium. Gen. Tech. Rep. PSW-GTR-229. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 139-153