Following a request from the European Commission, the EFSA Panel on Plant Health performed a pest
categorisation of Gymnosporangium spp. (non-EU), a well-defined and distinguishable group of fungal
plant pathogens of the family Pucciniaceae affecting woody species. Many different Gymnosporangium
species are recognised, of which at least 14 species are considered not to be native in the European
Union. All the non-EU Gymnosporangium species are not known to be present in the EU and are
regulated in Council Directive 2000/29/EC (Annex IAI) as harmful organisms whose introduction into
the EU is banned. Gymnosporangium spp. are biotrophic obligate plant pathogens. These rust fungi
are heteroecious as they require Juniperus, Libocedrus, Callitropsis, Chamaecyparis or Cupressus (telial
hosts) and rosaceous plants of subfamily Pomoideae (aecial hosts) to complete their life cycle. The
pathogens could enter the EU via host plants for planting (including artificially dwarfed woody plants)
and cut branches. They could establish in the EU, as climatic conditions are favourable and hosts are
common. They would be able to spread following establishment by movement of host plants for
planting and cut branches, as well as by natural dispersal. Should Gymnosporangium spp. (non-EU) be
introduced in the EU, impacts can be expected in orchards, ornamental trees and nurseries. On telial
hosts, these pathogens cause galls on stems, twigs and branches, and fusiform swellings on stems.
Foliar infections on aecial hosts may lead to severe defoliations. The main knowledge gap concerns the
limited available information on the biology, distribution range and impact of several non-EU
Gymnosporangium spp. The criteria assessed by the Panel for consideration of Gymnosporangium spp.
(non-EU) as potential quarantine pests are met, while, for regulated non-quarantine pests, the
criterion on the pest presence in the EU is not met