Pest categorisation of Melampsora medusae

Jeger, Michael; Bragard, Claude; Caffier, David; Candresse, Thierry; Chatzivassiliou, Elisavet; Dehnen‐Schmutz, Katharina; Gilioli, Gianni; Grégoire, Jean‐Claude; Miret, Josep Anton Jaques; MacLeod, Alan; Navarro, María Navajas; Niere, Björn; Parnell, Stephen; Potting, Roel; Rafoss, Trond; Rossi, Vittorio; Urek, Gregor; Bruggen, Ariena Van; Werf, Wopke Van der; West, Jon S.; Winter, Stephan; Boberg, Johanna; Gonthier, Paolo; Pautasso, Marco

doi:10.2903/j.efsa.2018.5354

Cited by 2 publications

(1 citation statement)

References 33 publications

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“…For more information on the biology of the pest see the EPPO Datasheet (EPPO, 2023b) and in the Scientific Opinion on the pest categorization of Melampsora medusae (EFSA, 2018).…”

Section: Introductionmentioning

confidence: 99%

PM 7/93 (2) Melampsora medusae

2023

EPPO Bulletin

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Melampsora medusae is a heteroecious rust fungus with Populus spp. as telial hosts (primary hosts on which uredinia and telia are produced) and various conifers as aecial hosts (on which spermagonia and aecia are pro duced). As is the case for other Melampsora species in fecting poplars, M. medusae causes abundant uredinia production on leaves, which can lead to premature de foliation and growth reduction. After several years of severe infection leading to repeated defoliation, the dis ease may predispose the trees to dieback or, for younger trees, even lead to death. Shain (1988) showed evidence of the existence of two formae speciales within M. medusae and named them M. medusae f. sp. deltoidae (syn deltoidis) and M. medusae f. sp. tremuloidae (syn 'tremuloidis'). Unlike M. medusae f. sp. deltoidae which is pathogenic on the poplars of the sections Aigeiros and Tacamahaca, i.e. Populus nigra, P. deltoides, P. trichocarpa, P. balsamifera, P. maximowiczii and their interspecific hybrids (P. × canadensis, P. × generosa and P. × jackii) (Frey et al., 2005; Vialle et al., 2011), the only telial host of M. medusae f. sp. tremuloidae with reported infections in nature in North America is P. tremuloides, belonging to the section Populus (EPPO, 2023a; Vialle et al., 2011).Melampsora medusae originates from North America. Since M. medusae was only reported in Europe on pop lars from the sections Aigeiros and Tacamahaca, and in respect with the host specialization, it can be concluded that only M. medusae f. sp. deltoidae has been reported in Europe so far (EPPO, 2023a; Pinon, 1991; Pinon & Frey, 2005).In addition to M. medusae f. sp. deltoidae, eight Melampsora species have been reported on poplars in Europe to date (Cellerino, 1999; Pinon, 1973; Vialle et al., 2011 Vialle et al., , 2013. Two of them, namely M. laricis-populina and M. allii-populina are pathogenic on the poplars of the sections Aigeiros and Tacamahaca. The six other species, namely M. aecidioides, M. laricis-tremulae, M. magnusiana, M. pinitorqua, M. pulcherrima and M. rostrupii, are only pathogenic on species of the sec tion Populus, i.e. P. alba, P. tremula and their interspe cific hybrids (Frey et al., 2005; Vialle et al., 2011). The eight other Melampsora species have been described on poplar in Europe are also present in other parts of the world (Vialle et al., 2011).For more information on the biology of the pest see the EPPO Datasheet (EPPO, 2023b) and in the Scientific Opinion on the pest categorization of Melampsora medusae (EFSA, 2018).A Flow diagram describing the diagnostic procedure for Melampsora medusae (including the specific diagnostic of M. medusae f. sp. tremuloidae) is presented in Figure 1. | I DEN T I T YName: Melampsora medusae Thümen. Other Scientific Names: Melampsora albertensis J.C. Ar thur, Uredo medusae Thümen (uredinial stage). Caeoma faulliana Hunter (aecial stage) is considered as a syn onym in Global Database. Taxonomic position: Fungi: Basidiomycota: Uredinales. Notes on taxonomy and nomenclature: Note on the name ...

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“…For more information on the biology of the pest see the EPPO Datasheet (EPPO, 2023b) and in the Scientific Opinion on the pest categorization of Melampsora medusae (EFSA, 2018).…”

Section: Introductionmentioning

confidence: 99%

PM 7/93 (2) Melampsora medusae

2023

EPPO Bulletin

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Pest categorisation of Melampsora medusae

Jeger¹,

Bragard²,

Caffier³

et al. 2018

EFS2

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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.

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Pest categorisation of Melampsora medusae

Cited by 2 publications

References 33 publications

PM 7/93 (2) Melampsora medusae

PM 7/93 (2) Melampsora medusae

Pest categorisation of Melampsora medusae

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