Risk assessment and reduction options for Cryphonectria parasitica in the EU

Following a request from the European Commission, the EFSA Plant Health (PLH) Panel performed arisk assessment forCryphonectria parasiticain the EU with the aim to assess the current EUphytosanitary requirements and identify the risk reduction options (RROs), which would preserve theprotected zone (PZ) status in some parts of the EU, where the pathogen is not known to occur.C. parasitica, a bark-inhabiting fungus causing blight of chestnut trees (Castaneaspp.), has a widedistribution in the EU (non-PZs). Three regulatory scenarios were considered for the whole riskassessment (RA) area: the current situation in non-PZs (scenario A0), the situation in the EU withoutmeasures (A1) and the current situation in PZs with additional RROs (A2). The Panel considered boththe risk of potential spread to PZs ofC. parasiticastrains currently present in the non-PZs and the riskof introduction from Third Countries and spread in non-PZs of new, virulent strains that would be ableto jeopardise the currently effective hypovirulence and cause severe impact. The number of newintroductions ofC. parasiticainto the EU is reduced by approximately a factor 5,000 (median values) inscenario A2compared to scenario A0. Under the A0,A1and A2scenarios, 2, 3.5 and 0.5 (medianvalues) EU Member States, respectively, are expected to be affected in the next 10 years due tospread ofC. parasiticastrains. The estimated relative impact on ecosystem services, due to theintroduction and spread in the EU of new, virulent strains, is higher for scenario A1compared toscenarios A0and A2. The current EU requirements and the additional RROs considered in scenario A2were assessed to be effective in reducing the risk of introduction and spread ofC. parasitica, thuspreserving the PZ status in some parts of the EU.