Ringspot disease of elm

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• Select section Ringspot disease of elm

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  Ringspot disease of elm

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  Kira Köpke, Susanne von Bargen, Artemis Rumbou, Carmen Büttner

  Humboldt-Universität zu Berlin, Albrecht Daniel Thaer-Institute, Division Phytomedicine, Berlin, Germany

  

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      General Information

      Urban pest & disease

      Ringspot disease of elm (Ulmus laevis) - Carlavirus ulmi (elm carlavirus)
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      Symptoms

      Chlorosis as chlorotic spot and ring spots, vein yellowing and vein banding, necrosis

      

      Carlavirus ulmi-associated leaf symptoms on infected elms. a) Chlorotic/necrotic spot, vein banding, vein yellowing, ringspots on leaves of trunk sprout; b) ringspots, chlorotic line pattern; c) ringspots, chlorotic line pattern; d) vein banding; e) +f) ringspots; g) +h) vein yellowing; i) chlorotic spots
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      Biology

      Elm carlavirus has been detected in the urban forest, as well as in natural and commercial forests. Most carlavirus species are transmitted naturally by aphids in the non-persistent manner; cowpea mild mottle virus is transmitted by whiteflies (Bemisia tabaci), pea streak virus, red clover vein mosaic virus and cowpea mild mottle virus are seedborne in their leguminous hosts. All carlaviruses are mechanically transmissible; some (e.g. carnation latent virus and passiflora latent virus) are sufficiently infectious to be transmitted this way in the field (ICTV, 2023). Nevertheless, mechanical inoculation of carlavirus fagi on Nicotiana benthamiana, Chenopodium amaranticolor and C. quinoa was not successful.
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      Hosts

      European white elm (Ulmus laevis Pall.) was found to be a natural host (Eisold, 2017).
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      Actions/ Management Recommendations

      The use of virus-tested plant material is highly recommended, especially if the beech trees are planted as street trees in cities, where growth under adverse environmental conditions have to be expected (Bandte et al. 2022). As also other viruses have been reported to infect Ulmus spp. (Büttner et al. 2023) and induce virus-like symptoms on leaves, reliable diagnosis of carlavirus ulmi should be done by molecular means, for instance virus-specific RT-PCR from symptom-bearing leaf material.
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      Quarantine

      Not regulated within the EU
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      Geography

      Carlavirus ulmi has been confirmed in Germany in (urban) forest trees.
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      Research & Science

      Elm carlavirus (genus: Carlavirus, family Betaflexiviridae) is a single stranded RNA-virus with a positive orientation. Phylogenetic analysis of open reading frames of the polymerase gene and coat protein gene confirm that the virus is a typical member of the genus and a novel species. Many epidemiological questions regarding the disease are still open. The virus is still not confirmed to be the causal agent of the observed ringspot-disease in elm, although virus detection correlates very well with the described typical symptoms. Carlaviruses have been reported to infect a wide range of plant species. However, the host range of individual species is usually limited.
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      References

      1.    Bandte M, von Bargen S, Landgraf M, Rybak M, Büttner C., 2022. Neue Erkenntnisse zu Viruserkrankungen an Bäumen und Konsequenzen für die Baumpflege. In: Dujesiefken D. (Ed.), Jahrbuch der Baumpflege 2022, Haymarket Media, Braunschweig, 143-161.

      2.    Betaflexiviridae | ICTV [WWW Document], n.d. URL https://ictv.global/report_9th/RNApos/Betaflexiviridae (accessed 5.5.23)

      3.    Büttner C, Landgraf M, Fernandez Colino HL, von Bargen S, Bandte M, 2023. Virus diseases of forest and urban trees. Chapter 3. In: Asiegbu F & Kovalchuk A (Eds.): Forest Microbiology. Tree diseases and pests, Volume 3. Elsevier 2023, London, United Kingdom, 61-97.

      4.    Eisold, A.-M.E., 2017. Molecular characterization of a new Carlavirus detected in German Ulmus laevis (Pall.) by Illumina high throughput sequencing. Communications in agricultural and applied biological sciences 82, 337–346. https://doi.org/10.18452/19940

      5.    Rumbou, A.; Vainio, E.J.; Büttner, C., 2021. Towards the Forest Virome: High-Throughput Sequencing Drastically Expands Our Understanding on Virosphere in Temperate Forest Ecosystems. Microorganisms, 9, 1730. https://doi.org/10.3390/microorganisms9081730

      6.    Vainio, E.J., Rumbou, A., Diez, J.J., Büttner, C., 2024. Forest Tree Virome as a Source of Tree Diseases and Biological Control Agents. Curr. For. Rep. 10, 153–174. https://doi.org/10.1007/s40725-024-00214-8