Pest categorisation of .

Following a request from the European Commission, the EFSA Plant Health (PLH) Panel performed a pest categorisation of , a well-defined and distinguishable fungus of the family Xylariaceae native to North America. The species was moved from the genus to the genus following a revision of the genus. The former species name is used in the Council Directive 2000/29/EC. is the causal agent of Hypoxylon canker of quaking aspen () and other poplars ( spp.). The pathogen has been reported in 16 EU Member States (MS), without apparent limiting ecoclimatic factors, but mostly (with the exception of Sweden) with a restricted distribution. is a protected zone (PZ) quarantine pest (Annex IIB) for Ireland and the UK (Northern Ireland). The main hosts present in the EU (, and hybrid poplars) are widespread throughout most of the risk assessment area, including the PZ. The main means of spread are wind-blown ascospores, plants for planting and wood with bark. is not currently reported to be of significant economic importance in the EU MS where the pathogen is reported, but has been shown to cause significant damage in the USA. Risk reduction options include appropriate site selection for poplar plantations, avoiding wounds, and debarking wood. The main uncertainties concern the distribution of the pathogen in the EU, the susceptibility of cultivated hybrid poplars to the pathogen and thus the potential damage to poplar plantations in the RA area. The criteria assessed by the Panel for consideration as potential PZ quarantine pest are met. The criterion of plants for planting being the main pathway for spread for regulated non-quarantine pests is not met: plants for planting are only one of the means of spread of the pathogen.