Commodity risk assessment of Castanea sativa plants from the United Kingdom.

The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by graftwood, whips, bare root plants and potted plants of Castanea sativa imported from the United Kingdom. The assessment was performed considering the available scientific information, including the technical information provided by the UK. All pests associated with the commodities were evaluated against specific criteria. Three EU regulated pests (Cryphonectria parasitica, Dryocosmus kuriphilus, Phytophthora ramorum), present in the UK and associated with the commodity, were considered relevant for this opinion. One pest that is not regulated in the EU (Phytophthora kernoviae) fulfilled all relevant criteria and was selected for further evaluation. For the selected pest, the risk mitigation measures described in the submitted technical dossier were evaluated. An expert judgement was given on the likelihood of pest freedom taking into consideration the risk mitigation measures acting on the pest, including uncertainties associated with the assessment. The degree of pest freedom varied among the commodities evaluated, with P. kernoviae being most frequently expected on the imported bare root and potted plants. The Expert Knowledge Elicitation indicated with 95% certainty that 9060 or more units per 10,000 will be free from P. kernoviae.