Pest categorisation of Melampsora medusae

摘要

Following a request from the European Commission, the Plant Health Panel performed a pest categorisation of , a well‐defined and distinguishable fungal species of the family Melampsoraceae. The pathogen is regulated in Annex of Council Directive 2000/29/ as a harmful organism whose introduction into the is banned. is a heteroecious rust fungus with spp. as primary telial hosts and various conifers ( , , , , and spp.) as secondary aecial hosts. is native to North America and has spread to South America, Africa, Asia, Oceania, as well as the , where f. sp. has been reported with a restricted distribution and low impacts from Belgium, south‐west France and southern Portugal. The pest could spread to other countries, via dissemination of spores, movement of host plants for planting and cut branches. Climate is assumed not to be a limiting factor for the establishment of the pathogen in the . is the most widespread and important Melampsora rust in North America. In western Canada, extensive damage has been reported to conifers and spp. in nurseries and plantations as well as in woodlands. is damaging in both Australia and New Zealand. The pest could have economic and environmental impacts in the if aggressive isolates of were introduced into the . Import prohibition of host plants for planting is an available measure to reduce the risk of further introductions. Some resistant cultivars are available. Moreover, increasing the genetic diversity of poplar plantations can prevent disease impacts. The main uncertainty concerns the factors explaining the low pathogenicity of the populations of present in the . The criteria assessed by the Panel for consideration as a potential quarantine pest are met (the pest is present, but with a restricted distribution, and is officially under control). Given that plants for planting are not the main pathway of spread, not all criteria for consideration as a regulated non‐quarantine pest are met.