Pest Categorisation of Melampsora Medusae

Pest Categorisation of Melampsora Medusae. Jeger, M., Bragard, C., Caffier, D., Candresse, T., Chatzivassiliou, E., Dehnen-Schmutz, K., Gilioli, G., Grégoire, J., Jaques Miret, J. A., MacLeod, A., Navajas Navarro, M., Niere, B., Parnell, S., Potting, R., Rafoss, T., Rossi, V., Urek, G., Van Bruggen, A., Van der Werf, W., West, J., Winter, S., Boberg, J., Gonthier, P., & Pautasso, M. 16(7):e05354+.

Paper doi abstract bibtex

Following a request from the European Commission, the EFSA Plant Health Panel performed a pest categorisation of Melampsora medusae, a well-defined and distinguishable fungal species of the family Melampsoraceae. The pathogen is regulated in Annex IAI of Council Directive 2000/29/EC as a harmful organism whose introduction into the EU is banned. M. medusae is a heteroecious rust fungus with Populus spp. as primary telial hosts and various conifers (Larix, Pinus, Pseudotsuga, Abies, Picea and Tsuga spp.) as secondary aecial hosts. M. medusae is native to North America and has spread to South America, Africa, Asia, Oceania, as well as the EU, where M. medusae f. sp. deltoidae has been reported with a restricted distribution and low impacts from Belgium, south-west France and southern Portugal. The pest could spread to other EU 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 EU. M. medusae is the most widespread and important Melampsora rust in North America. In western Canada, extensive damage has been reported to conifers and Populus spp. in nurseries and plantations as well as in woodlands. M. medusae is damaging in both Australia and New Zealand. The pest could have economic and environmental impacts in the EU if aggressive isolates of M. medusae were introduced into the EU. Import prohibition of host plants for planting is an available measure to reduce the risk of further introductions. Some resistant Populus 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 M. medusae present in the EU. 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. [Excerpt: Conclusions] [...] [::Identity of the pest] The identity of the pest as a species is clear. [] [...] [] The recent change in name from Ceratocystis fagacearum to Bretziella fagacearum may take time for acceptance by the scientific community. [...] [::Absence/presence of the pest in the EU territory] M. medusae is present, although not widespread, in the EU (and only represented by M. medusae f. sp. deltoidae). It is reported as present with few occurrences both in Belgium and France, and present with a restricted distribution in South Portugal. [...] [::Regulatory status] M. medusae is regulated by Council Directive 2000/29/EC (Annex IAI) as a harmful organism whose introduction into, and spread within, all Member States shall be banned. [] [...] [::Pest potential for entry, establishment and spread in the EU territory] Entry: the pest could enter the EU via host plants for planting and cut branches. [] Establishment: hosts and favourable climatic conditions are widespread in the risk assessment area. [] Spread: hosts and favourable climatic conditions are widespread in the risk assessment area. [] [...] [] Plants for planting are not the main means of spread, as the pathogen can also spread via cut branches and aerial dissemination of spores. [] [...] [] There is uncertainty about which factors are limiting the spread of M. medusae in the EU MS which have reported the pathogen (overwintering problems, host alternation or ecological constraints). [] There is uncertainty about the level of susceptibility of the native P. alba and P. tremula. [...] [::Potential for consequences in the EU territory] The introduction into the EU of aggressive isolates of M. medusae (of both the already present M. medusae f. sp. deltoidae and the not known to occur M. medusae f. sp. tremuloides) would have economic and environmental impacts in woodlands, poplar plantations and nurseries. [] [...] [] The introduction into the EU of aggressive isolates of M. medusae (of both the already present M. medusae f. sp. deltoidae and the not known to occur M. medusae f. sp. tremuloides) would have an impact on the intended use of plants for planting. [] [...] [] It is unclear if low pathogenicity of populations of either f. sp. of M. medusae may be due to their reduced life cycle characteristics. [...] [::Available measures] Import prohibition of host plants for planting is an available measure to reduce the risk of introduction. [] Some resistant Populus cultivars are available. Moreover, increasing host genetic diversity can prevent disease impacts. [] [...] [] Production of plants for planting in pest free areas and places of production can prevent pest presence on plants for planting. [] [...] [] The effectiveness of pest free areas for the production of clean nursery stock is uncertain, due to the long-distance dispersal potential of the rust. [...] [::Conclusion on pest categorisation] The criteria assessed by the Panel for consideration as a potential quarantine pest are met. The pathogen is present in the EU but with a restricted distribution and is under official control. [] [...] [] The criterion on plants for planting as the main pathway of spread is not met. [...] [::Aspects of assessment to focus on/scenarios to address in future if appropriate] The main knowledge gap concerns the factors responsible for the low aggressiveness of the populations of M. medusae present in Europe. [...]

@article{jegerPestCategorisationMelampsora2018,
  title = {Pest Categorisation of {{Melampsora}} Medusae},
  author = {Jeger, Michael and Bragard, Claude and Caffier, David and Candresse, Thierry and Chatzivassiliou, Elisavet and Dehnen-Schmutz, Katharina and Gilioli, Gianni and Grégoire, Jean-Claude and Jaques Miret, Josep A. and MacLeod, Alan and Navajas Navarro, Maria and Niere, Björn and Parnell, Stephen and Potting, Roel and Rafoss, Trond and Rossi, Vittorio and Urek, Gregor and Van Bruggen, Ariena and Van der Werf, Wopke and West, Jonathan and Winter, Stephan and Boberg, Johanna and Gonthier, Paolo and Pautasso, Marco},
  date = {2018-07},
  journaltitle = {EFSA Journal},
  volume = {16},
  pages = {e05354+},
  issn = {1831-4732},
  doi = {10.2903/j.efsa.2018.5354},
  url = {https://doi.org/10.2903/j.efsa.2018.5354},
  abstract = {Following a request from the European Commission, the EFSA Plant Health Panel performed a pest categorisation of Melampsora medusae, a well-defined and distinguishable fungal species of the family Melampsoraceae. The pathogen is regulated in Annex IAI of Council Directive 2000/29/EC as a harmful organism whose introduction into the EU is banned. M. medusae is a heteroecious rust fungus with Populus spp. as primary telial hosts and various conifers (Larix, Pinus, Pseudotsuga, Abies, Picea and Tsuga spp.) as secondary aecial hosts. M. medusae is native to North America and has spread to South America, Africa, Asia, Oceania, as well as the EU, where M. medusae f. sp. deltoidae has been reported with a restricted distribution and low impacts from Belgium, south-west France and southern Portugal. The pest could spread to other EU 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 EU. M. medusae is the most widespread and important Melampsora rust in North America. In western Canada, extensive damage has been reported to conifers and Populus spp. in nurseries and plantations as well as in woodlands. M. medusae is damaging in both Australia and New Zealand. The pest could have economic and environmental impacts in the EU if aggressive isolates of M. medusae were introduced into the EU. Import prohibition of host plants for planting is an available measure to reduce the risk of further introductions. Some resistant Populus 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 M. medusae present in the EU. 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.

[Excerpt: Conclusions] [...] [::Identity of the pest] The identity of the pest as a species is clear. [] [...] [] The recent change in name from Ceratocystis fagacearum to Bretziella fagacearum may take time for acceptance by the scientific community. [...]

[::Absence/presence of the pest in the EU territory] M. medusae is present, although not widespread, in the EU (and only represented by M. medusae f. sp. deltoidae). It is reported as present with few occurrences both in Belgium and France, and present with a restricted distribution in South Portugal. [...]

[::Regulatory status] M. medusae is regulated by Council Directive 2000/29/EC (Annex IAI) as a harmful organism whose introduction into, and spread within, all Member States shall be banned. [] [...]

[::Pest potential for entry, establishment and spread in the EU territory] Entry: the pest could enter the EU via host plants for planting and cut branches.

[] Establishment: hosts and favourable climatic conditions are widespread in the risk assessment area.

[] Spread: hosts and favourable climatic conditions are widespread in the risk assessment area. [] [...]

[] Plants for planting are not the main means of spread, as the pathogen can also spread via cut branches and aerial dissemination of spores. [] [...]

[] There is uncertainty about which factors are limiting the spread of M. medusae in the EU MS which have reported the pathogen (overwintering problems, host alternation or ecological constraints).

[] There is uncertainty about the level of susceptibility of the native P. alba and P. tremula. [...]

[::Potential for consequences in the EU territory] The introduction into the EU of aggressive isolates of M. medusae (of both the already present M. medusae f. sp. deltoidae and the not known to occur M. medusae f. sp. tremuloides) would have economic and environmental impacts in woodlands, poplar plantations and nurseries. [] [...] [] The introduction into the EU of aggressive isolates of M. medusae (of both the already present M. medusae f. sp. deltoidae and the not known to occur M. medusae f. sp. tremuloides) would have an impact on the intended use of plants for planting. [] [...] [] It is unclear if low pathogenicity of populations of either f. sp. of M. medusae may be due to their reduced life cycle characteristics. [...]

[::Available measures] Import prohibition of host plants for planting is an available measure to reduce the risk of introduction.

[] Some resistant Populus cultivars are available. Moreover, increasing host genetic diversity can prevent disease impacts. [] [...]

[] Production of plants for planting in pest free areas and places of production can prevent pest presence on plants for planting. [] [...]

[] The effectiveness of pest free areas for the production of clean nursery stock is uncertain, due to the long-distance dispersal potential of the rust. [...]

[::Conclusion on pest categorisation] The criteria assessed by the Panel for consideration as a potential quarantine pest are met. The pathogen is present in the EU but with a restricted distribution and is under official control. [] [...]

[] The criterion on plants for planting as the main pathway of spread is not met. [...]

[::Aspects of assessment to focus on/scenarios to address in future if appropriate] The main knowledge gap concerns the factors responsible for the low aggressiveness of the populations of M. medusae present in Europe. [...]},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-14636135,~to-add-doi-URL,abies-spp,disturbances,efsa,efsa-scientific-opinion,europe,forest-pests,forest-resources,fungal-diseases,fungi,larix-spp,melampsora-medusae,picea-spp,pinus-spp,plant-pests,populus-spp,pseudotsuga-spp,tsuga-spp},
  number = {7}
}

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