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Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a pest categorisation of Stegophora ulmea, a well-defined and distinguishable fungal species of the family Sydowiellaceae. S. ulmea causes a tree disease known as black spot of elm (Ulmus spp.). The pathogen is reported from North America (native range) and Asia (Far-East Russia and China), but not from the EU. S. ulmea is regulated in Council Directive 2000/29/EC (Annex IIAI) as a harmful organism whose introduction into the EU is banned on plants of Ulmus L. and Zelkova L., intended for planting, other than seeds. The pathogen has been occasionally intercepted on imported bonsai plants (and then destroyed) in the Netherlands and the UK. It could enter the EU and spread within it via plants for planting (including bonsai) and cut branches. Hosts and favourable climatic conditions are common in the EU. The European native elm species Ulmus glabra and Ulmus laevis were found to be more susceptible to the disease than North American elm species, but information is lacking on Ulmus minor. The disease is rarely fatal, but S. ulmea can cause considerable damage, particularly in wet summers. Reduction of inoculum by the removal of leaf debris and avoiding overhead watering in nurseries can reduce the risk of spread of the pathogen. The main knowledge gaps concern (i) the distribution of the pest in Asian countries, (ii) the relative role of the means of entry/spread and (iii) the potential consequences in mature tree plantations and native woodland. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated non-quarantine pests, the criterion on the pest presence in the EU is not met.

The Panel on Plant health performed a pest categorisation of the larch web-spinning sawfly Cephalcia lariciphila (Hymenoptera: Pamphiliidae) for the EU. The insect has been reported in 11 EU Member States (MSs). It is a quarantine pest listed in Annex IIB of Council Directive 2000/29/EC. Protected zones are in place in Ireland and the UK (Northern Ireland, Isle of Man and Jersey). C. lariciphila can feed on all species of the genus Larix. There have been reported outbreaks in the Czech Republic, Germany, the Netherlands and the UK (England and Wales) in plantations of European larch (Larix decidua) and Japanese larch (Larix kaempferi = Larix leptolepis). C. lariciphila is absent in the protected zones. The pest can enter the protected zones by human-assisted spread or by natural spread from EU areas where the pest is present. Plants for planting are considered the most important pathway for the pest. The pest can establish in the protected zones because the climatic conditions are similar to those of the 11 MSs where C. lariciphila is established, and the pest’s main host plants are present. The prepupae overwinter in the litter, the adults emerge during May–June, and each female lays 30–40 eggs in slits in mature needles. The larvae feed on the needles through four instars. There is one generation per year; some of the prepupae undergo prolonged diapause for more than 1 year. The impact where the pest occurs is mainly related to the loss of tree growth following defoliation, while tree mortality was locally observed only after repeated defoliation. However, impact is likely to be mitigated by local biological control agents. All criteria assessed by EFSA above for consideration as a potential protected zone quarantine pest and as a potential regulated non-quarantine pest were met.

The Panel on Plant Health performed a pest categorisation of Elsinoe fawcettii and E. australis, the causal agents of citrus scab diseases, for the EU. The identities of the pests are well-established and reliable methods exist for their detection/identification. The pests are listed in Annex IIAI of Directive 2000/29/EC as Elsinoe spp. and are not known to occur in the EU. Species and hybrids of citrus (Family Rutaceae) are affected by E. fawcettii and E. australis, with the latter having a more restricted host range and geographical distribution compared to the former. The status of Simmondsia chinensis (jojoba) as a host of E. australis is uncertain. The pests could potentially enter the EU on host plants for planting and fruit originating in infested Third countries. The current distribution of the pests, climate matching and the use of irrigation in the EU citrus-growing areas suggest that the pests could establish and spread in the EU citrus-growing areas. Uncertainty exists on whether cultural practices and control methods, currently applied in the EU, would prevent the establishment of the pests. In the infested areas, the pests cause scab pustules on host leaves and fruit resulting in yield/quality losses. It is expected that the introduction and spread of the pests in the EU could impact citrus production. Cultural practices and chemical control measures may reduce the inoculum sources and to some extent the disease incidence, but they cannot eliminate the pests. Phytosanitary measures are available to mitigate the risk of introduction and spread of the pests in the EU. E. fawcettii and E. australis meet all the criteria assessed by EFSA for consideration as potential Union quarantine pests. As those pests are not known to occur in the EU, this criterion to consider them as Union regulated non-quarantine pests is not met.

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) performed a pest categorisation of Davidsoniella virescens, a well-defined and distinguishable fungal species of the family Ceratocystidaceae. The species was moved from the genus Ceratocystis to the genus Davidsoniella following a revision of the family. The former species name Ceratocystis virescens is used in the Council Directive 2000/29/EC. The pathogen is regulated in Annex IIAI as a harmful organism whose introduction into the EU is banned on plants (other than fruit and seeds) and wood (including wood which has not kept its natural round surface) of Acer saccharum, originating in the USA and Canada. The fungus is native to eastern North America and causes symptoms mainly on A. saccharum, but also on Liriodendron tulipifera. The fungus is also reported as a saprotroph on various hardwood species. The pest could enter the EU via wood, plants for planting and cut branches. Hosts and favourable climatic conditions are widespread in the EU. The pest would be able to spread following establishment through sap-feeding insects, root grafts and movement of infected wood and plants for planting. The pest introduction could have impacts on Acer spp. and L. tulipifera trees in the EU, by causing wilting, yellowing and the development of small leaves, as well as dieback of branches and, eventually, the death of trees. Avoiding damaging trees (as wounding facilitates infection of the fungus) and maintaining healthy trees (as tree stress facilitates the disease) are available measures to reduce impacts. The main knowledge gaps concern (i) the biology and epidemiology of the pathogen (including the saprotrophic form), (ii) the role of insect vectors for entry and spread, and (iii) the susceptibility of Acer spp. either native to or more recently established in Europe. The criteria assessed by the Panel for consideration as potential quarantine pest are met. For regulated non-quarantine pe