Health of elms and Dutch elm disease in Estonia

  • Liina Jürisoo
  • Kalev Adamson
  • Allar Padari
  • Rein DrenkhanEmail author


During three years, 2014–2016, Dutch elm disease (further DED) was investigated on 1225 elm trees at 4 different sampling sites and 2 sub-sites in Estonia. For the first time, both subspecies of the invasive pathogen Ophiostoma novo-ulmi: O. novo-ulmi subsp. novo-ulmi, and O. novo-ulmi subsp. americana, were detected by col1 and cu genes in Estonia and north-eastern Europe. Ophiostoma novo-ulmi subsp. americana was identified only at one site in northern Estonia, in Tallinn. In addition, during our assessments, the health of elms there appeared worse than at other sampling sites: O. novo-ulmi subsp. americana demonstrated higher aggressiveness. Simultaneous occurrence of both subspecies and their hybrids was not detected. A repeat survey of 109 elms in 2014 and 2016 demonstrated ca. 22% probability of mortality within 24 months, irrespective of urban vs. rural habitat. In sub-site A1 in Tallinn, O. novo-ulmi subsp. americana has been found since 2013. DED signs were noted on 39% of all 1225 surveyed trees. Among the assessed elm species, Ulmus laevis showed higher resistance than U. glabra: 82% and 66% of trees, respectively, showed high vitality. In addition, no U. laevis trees were found dead, compared to 18% of the U. glabra.


DED Invasive species Ophiostoma novo-ulmi subsp. americana O. novo-ulmi subsp. novo-ulmi Hybrid Ulmus spp. 



This study was supported by the Estonian Science Foundation grants PSG136, IUT21-04, the Estonian Environmental Investments Centre and Estonian University of Life Sciences project P170053MIMK. We would like to thank Dr. Märt Hanso for valuable suggestions and comments to the manuscript and Mr. Terry Bush (from Wisconsin, USA) for the English revision. My very special thanks to the people who helped to collect the samples and data: Guy and Philip Meilleur, Priit Oks, Kirsika Kapp and my volleyball teammates.

Compliance with ethical standards

The authors declare that ethical standards have been followed and that no human participants or animals were involved in this research.

Conflict of interest

The authors declare that they have no competing interests.


  1. Aaspõllu, A. (1999). Lehtpuude kultivarid Eestis (Cultivars of deciduous trees in Estonia) [in Estonian], H. Sander (ed.) Dendroloogilised uurimused Eestis (Dendrological researches in Estonia) (pp. 110-137).Google Scholar
  2. Abner, O., Konsa, S., Lootus, K., & Sinijärv, U. (2007). Eesti pargid 1 (Estonian parks 1) [in Estonian]. Keskkonnaministeerium, Muinsuskaitseamet, Varrak, Tallinn. 423 p.Google Scholar
  3. Abner, O., Konsa, S., Lootus, K., & Sinijärv, U. (2012). Eesti pargid 2 (Estonian parks 2) [in Estonian]. Keskkonnaministeerium, Muinsuskaitseamet, Varrak, Tallinn. 647 p.Google Scholar
  4. Adamson, K., Drenkhan, R., & Hanso, M. (2015a). Invasive brown spot needle blight caused by Lecanosticta acicola in Estonia. Scandinavian Journal of Forest Research., 30(7), 587–593. Scholar
  5. Adamson, K., Kalvina, D., Drenkhan, R., Gaitnieks, T., & Hanso, M. (2015b). Diplodia sapinea is colonizing the native Scots pine (Pinus sylvestris) in the northern Baltics. European Journal of Plant Pathology., 143(2), 343–350. Scholar
  6. Adamson K., Laas M., Drenkhan R., & Hanso M. (2018). Quarantine pathogen Lecanosticta acicola, observed at its jump from an exotic host to the native Scots pine in Estonia. Baltic Forestry, 24(1), 36–41.Google Scholar
  7. Adamson, K., Mullett, M. S., Solheim, H., Barnes, I., Müller, M. M., Hantula, J., et al. (2018b). Looking for relationships between the populations of Dothistroma septosporum in northern Europe and Asia. Fungal Genetics and Biology, 110, 15–25. Scholar
  8. Astover, A. Kõlli, R., Roostalu, H. Reintam, L., & Leedu, E. (2012). Mullateadus (Soil Science) [in Estonian]. Estonian University of Life Sciences. 486 p.Google Scholar
  9. Atkinson, T. H. (2017). Scolytus. Bark and Ambrosia Beetles. Available online at Accessed 15 Dec 2017.
  10. Barstow, M., & Harvey-Brown, Y. (2017). Ulmus laevis. The IUCN Red list of threatened species 2017: e.T61967009A61967013. Available online at, last accessed Dec. 12, 2018.
  11. Barstow, M., & Rivers, M.C. (2017). Ulmus glabra. The IUCN Red list of threatened species 2017: e.T61966807A61966819. Available online at, last accessed Dec. 12, 2018.
  12. Barstow, M., Rivers, M. C., & Harvey-Brown, Y. (2017). Ulmus minor. The IUCN Red list of threatened species 2017: e.T19218731A69047375. Available online at, last accessed Dec. 12, 2018.
  13. Bernier, L., Aoun, M., Bouvet, G. F., Comeau, A., Dufour, J., et al. (2014). Genomics of the Dutch elm disease pathosystem: Are we there yet? iForest Biogeosciences and Forestry Collection: 3rd International Elm Conference “The elms after 100 years of Dutch Elm disease”, 8, 149-157. (A. Santini, et al., ed.) Florence, Italy.
  14. Blumenstein, K. (2015). Endophytic Fungi in Elms. PhD thesis, SLU. 84 p.Google Scholar
  15. Brasier, C. M. (2008). The biosecurity threat to the UK and global environment from international trade in plants. Plant Pathology, 57, 792–808. Scholar
  16. Brasier, C. M., & Buck, K. W. (2001) Rapid evolutionary changes in a globally invading fungal pathogen (Dutch elm disease). Biological Invasions, 3, 223–233.Google Scholar
  17. Brasier, C. M., & Kirk, S. A. (2001). Designation of the EAN and NAN races of Ophiostoma novo-ulmi as subspecies. Mycological Research, 105(5), 547–554. Scholar
  18. Brasier, C. M., & Kirk, S. A. (2010). Rapid emergence of hybrids between the two subspecies of Ophiostoma novo-ulmi with a high level of pathogenic fitness. Plant Pathology, 59, 186–199. Scholar
  19. Brasier, C., Buck, K., Paoletti, M., & Crawford, L. (2004). Molecular analysis of evolutionary changes in populations of Ophiostma novo-ulmi. Investigación agraria. Sistemas y recursos forestales, 13(1), 93–103. Scholar
  20. Brunet, J., Zalapa, J., Pecori, F., & Santini, A. (2013). Hybridization and introgression between the exotic Siberian elm, Ulmus pumila, and the native field elm, U. minor, in Italy. Biological Invasions, 15, 2717–2730. Scholar
  21. Büchel, K., Fenning, T., Gershenzon, J., Hilker, M., & Meiners, T. (2016). Elm defence against herbivores and pathogens: Morphological, chemical and molecular regulation aspects. Phytochemistry Reviews, 15, 961–983. Scholar
  22. Buiteveld, J., Van Der Werf, B., & Hiemstra, J. A. (2014). Comparison of commercial elm cultivars and promising unreleased Dutch clones for resistance to Ophiostoma novo-ulmi. iForest Biogeosciences and Forestry Collection: 3rd International Elm Conference “The elms after 100 years of Dutch Elm disease”, 8, 158-164. (A. Santini, et al., ed.) Florence, Italy.
  23. Caulton, E., Aitken, W., & Rashid, N. (1998). Aerobiological aspects of elm (Ulmus spp.) in south-East Scotland in relation to elm decline from Dutch Elm disease (1976-1996). Aerobiologia, 14, 147–153.CrossRefGoogle Scholar
  24. Collin, E. (2002). Strategies and guidelines for the conservation of the genetic resources of Ulmus spp. "Noble Hardwoods" network. In S. Borelli (Ed.), Report of the fourth and fifth meetings, Sept. 1999 and May 2001 (pp. 50–67). Rome: International Plant Genetic Resources Institute.Google Scholar
  25. Corfixen, P., & Parmasto, E. (2005). Hymenochaete ulmicola sp. nov. (Hymenochaetales). Mycotaxon, 91, 465–469.Google Scholar
  26. Dehnen-Schmutz, K., Holdenrieder, O., Jeger, M. J., & Pautasso, M. (2010). Structural change in the international horticultural industry: Some implications for plant health. Scientia Horticulturae, 125, 1–15. Scholar
  27. Dobbs, C., Martinez-Harms, M. J., & Kendal, D. (2017). The ecosystem service concept and its importance for socio-ecological systems. In Routledge handbook of urban forestry (pp. 51–64). London: Routledge.Google Scholar
  28. Drenkhan, R., Sander, H., & Hanso, M. (2014). Introduction of Mandshurian ash (Fraxinus mandshurica Rupr.) to Estonia: Is it related to the current epidemic on European ash (F. excelsior L.)? European Journal of Forest Research, 133(5), 769–781. Scholar
  29. Drenkhan, R., Adamson, K., & Hanso, M. (2015). Fraxinus sogdiana, a Central Asian ash species, is susceptible to Hymenoscyphus fraxineus&nbsp. Plant Protection Science, 51(No. 3), 150–152.Google Scholar
  30. Drenkhan, R., Riit, T., Adamson, K., & Hanso, M. (2016). The earliest samples of Hymenoscyphus albidus vs. H. fraxineus in Estonian mycological herbaria. Mycological Progress, 15, 835–844. Scholar
  31. Drenkhan, R., Solheim, H., Bogacheva, A., Riit, T., Adamson, K., Drenkhan, T., Maaten, T., & Hietala, A. M. (2017). Hymenoscyphus fraxineus is a leaf pathogen of local Fraxinus species in the Russian Far East. Plant Pathology, 66, 490–500. Scholar
  32. Dvořák, M., Tomšovský, M., Jankovský, L., & Novotný, D. (2007). Contribution to Identify the Causal Agents of Dutch Elm Disease in the Czech Republic. Plant Protection Science, 43(4), 142–145.Google Scholar
  33. EPPO (2017). EPPO Global database. Available online at; last accessed Dec. 15, 2017.
  34. Estonian Soil Map (2018). Estonian land board geoportal. Available online at, last accessed Dec. 31, 2018.
  35. Flower, C. E., Slavicek, J. M., Lesser, D., Eshita, S., & Pinchot, C. C. (2017). Canopy decline assessments in American elm after inoculation with different doses of Ophiostoma ulmi and O. novo-ulmi. In: Proceedings of the American Elm Restoration Workshop 2016. C. C. Pinchot, K. S. Knight, L. M. Haugen, C. E. Flower, & J. M. Slavicek (eds.). United States Department of Agriculture (pp. 24-29).
  36. Gardes, M., & Bruns, T. D. (1993). ITS primers with enhanced specificity for basidiomycetes – Application of the identification of mycorrhizae and rusts. Molecular Ecology, 2, 113–118. Scholar
  37. Ghelardini, L., Luchi, N., Pecori, F., Pepori, A. L., Danti, R., Rocca, G. D., et al. (2017). Ecology of invasive forest pathogens. Biological Invasions, 19, 3183–3200. Scholar
  38. Gibbs, J. N. (1978) Intercontinental Epidemiology of Dutch Elm Disease. Annual Review of Phytopathology, 16(1), 287–307.Google Scholar
  39. Gibb, E. A., & Hausner, G. (2005). Optional mitochondrial introns and evidence for a homing-endonuclease gene in the mtDNA rnl gene in Ophiostoma ulmi s. lat. Mycological Research, 109(10), 1112–1126. Scholar
  40. Guries, R. P., & Smalley, E. B. (2000). Once and future elms: Classical and molecular approaches to Dutch elm disease resistance. In C. P. Dunn (Ed.), The Elms (pp. 231–248). Boston: Springer.CrossRefGoogle Scholar
  41. Hall, T. A. (2013). Biological sequence alignment editor and analysis program for Windows 95/98/NT/2000/XP/7. BioEdit. Available online at; last accessed Dec. 15, 2017.
  42. Hannunen, S., & Marinova-Todorova, M. (2016). Pest risk assessment for Dutch elm disease. Evira. Available online at; last accessed Dec. 15, 2017.
  43. Hanso, M., & Drenkhan, R. (2007). Metsa- ja linnapuud ilmastiku äärmuste vaevas (Trees in forests and towns are suffering from the extreme weather conditions) [in Estonian]. Eesti Loodus (Estonian Nature), 58(4), 6–13.Google Scholar
  44. Hanso, M., & Drenkhan, R. (2009). Diplodia pinea is a new pathogen on Austrian pine (Pinus nigra) in Estonia. Plant Pathology, 58(4), 797–797. Scholar
  45. Hanso, M., & Drenkhan, R. (2013). Simple visualization of climate change for improving the public perception in forest pathology. Forestry Studies, 58, 37–45. Scholar
  46. Hillier N (1991). The Hillier Manual of Trees & Shrubs. J. G. Hillier, & A. J. Coombes (eds.), (pp. 508–512). Winchester: David & Charles.Google Scholar
  47. IUCN (2018). The IUCN Red list of threatened species. Version 2018-2. Available online at:, last accessed Dec.12, 2018.
  48. Jüriado, I., Liira, J., & Paal, J. (2009). Diversity of epiphytic lichens in boreo-nemoral forests on the north-Estonian limestone escarpment: The effect of tree level factors and local environmental conditions. The Lichenologist, 41(1), 81–96. Scholar
  49. Kaar, E. (2011). Jalakas ja künnapuu Eestis (elms in Estonia) [in Estonian]. Eesti Loodus (Estonian Nature)., 62(3).Google Scholar
  50. Kalamees, K. (2011). Roosa võrkheinik: Seenharuldus jalakal (wrinkled peach: Rare fungus on elms) [in Estonian]. Eesti Loodus (Estonian Nature), 62(10), 41–41.Google Scholar
  51. Kalda, A. (1995). Broadleaved forests in Estonia. Consortium Masingii. Aaviksoo, K, Kull, K., Paal, J., & Trass, H. (eds.) (pp.89-95).Google Scholar
  52. Keskkonnaagentuur (2015). Eesti meteoroloogia aastaraamat 2014 (Estonian Meteorological Yearbook 2014) [In Estonian]. A. Kallis, K. Loodla, E. Tillmann, M. Krabbi, R. Pärg, K. Vint, A. Jõeveer, & E. Juust (compilers). Eesti Meteoroloogia ja Hüdroloogia Instituut. Available online at, last accessed Dec. 15, 2017.
  53. Keskkonnaagentuur (2016). Eesti meteoroloogia aastaraamat 2015 (Estonian Meteorological Yearbook 2015 [In Estonian]. A. Kallis, K. Loodla, E. Tillmann, M. Krabbi, R. Pärg, K. Vint, & A. Jõeveer (compilers). Eesti Meteoroloogia ja Hüdroloogia Instituut. Available online at, last accessed Dec. 15, 2017.
  54. Keskkonnaagentuur (2017). Eesti meteoroloogia aastaraamat 2016 (Estonian Meteorological Yearbook 2016) [In Estonian]. K. Loodla, E. Tillmann, A. Kallis, R. Pärg, K. Vint, E. Juust, & M. Krabbi (compilers). Eesti Meteoroloogia ja Hüdroloogia Instituut. Available online at, last accessed Dec. 15, 2017.
  55. Kirisits, T. (2013). Dutch elm disease and other Ophiostoma diseases. In P. Gonthier & G. Nicolotti (Eds.), Infectious forest diseases (pp. 256–282). Wallingford: CABI Publishing.CrossRefGoogle Scholar
  56. Konrad, H., Kirisits, T., Riegler, M., Halmschla, E., & Stauffer, C. (2002). Genetic evidence for natural hybridization between the Dutch elm disease pathogens Ophiostoma novo-ulmi ssp. novo-ulmi and O. novo-ulmi ssp. americana. Plant Pathology, 51, 78–84. Scholar
  57. Kristian, J. (1939). Jalakapuistu (Elmstand) [in Estonian]. Estonian Forest (Eesti mets), 5, 171–172.Google Scholar
  58. Kukk, T., & Kull, T. (2005). Eesti taimede levikuatlas (Atlas of the Estonian Flora) [in Estonian] (p. 528). Tartu: Eesti Maaülikooli Põllumajandus- ja Keskkonnainstituut.Google Scholar
  59. La Porta, N., Capretti, P., Thomsen, I. M., Kasanen, R., Hietala, A. M., & Von Weissenberg, K. (2008). Forest pathogens with higher damage potential. In Symposium contribution: The Effects of Climate Change on Tree Diseases. Canadian Journal of Plant Pathology, 30, 177–195. Scholar
  60. Laas, E., & Treumuth, S. (2006). Voltveti mõisapargi ja Tihemetsa arboreetumi dendroloogiline inventuur (Dendrological inventory of Voltvet manor park and Tihemetsa arboretum) [in Estonian]. Tartu, 78 p.Google Scholar
  61. Laasimer, L. (1965). Eesti NSV taimkate (Vegetation of Estonian SSR) [in Estonian] (p. 421). Tallinn: Valgus.Google Scholar
  62. Łakomy, P., Kwaśna, H., Kuźmiński, R., Napierała-Filipiak, A., Filipiak, M., Behnke, K., & Behnke-Borowczyk, J. (2016). Investigation of Ophiostoma population infected elms in Poland. Dendrobiology, 76, 137–144. Scholar
  63. Leht, M. (2018). Ulmus laevis. eBiodiversity, available online at, last accessed Dec. 12, 2018.
  64. Lepik, E. (1940). Estonia: The elm disease in the country. International Bulletin of Plant Protection, International Review of Agriculture., 31, 2–2.Google Scholar
  65. Liebhold, A. M., Brockerhoff, E. G., Kalisz, S., Nuňez, M. A., Wardle, D. A., & Wingfield, M. J. (2017). Biological invasions in forest ecosystems. Biological Invasions, 19, 3437–3458. Scholar
  66. Lilleleht, V. (Ed.). (2008). Eesti Punane Raamat (Red data book of Estonia) [in Estonian]. Tartu: Commission for Nature Conservation of the Estonian Academy of Sciences.Google Scholar
  67. Martín, J. A., Solla, A., Esteban, L. G., de Palacios, P., & Gil, L. (2009). Bordered pit and ray morphology involvement in elm resistance to Ophiostoma novo-ulmi. NRC Research Press (pp. 420-429).
  68. Martín, J. A., Fuentes-Utrilla, P., Gil, L., & Witzell, J. (2010). Broadleaved forests in southern Sweden: Management for multiple goals. Ecological Bulletins, 53, 209–224.Google Scholar
  69. Martín, J. A., Solla, A., Ruiz-Villar, M., & Gil, L. (2013a). Vessel length and conductivity of Ulmus branches: Ontogenetic changes and relation to resistance to Dutch elm disease. Trees, 27, 1239–1248. Scholar
  70. Martín, J. A., Witzell, J., Blumenstein, K., Rozpedowska, E., Helander, M., Sieber, T. N., & Gil, L. (2013b). Resistance to Dutch Elm disease reduces presence of xylem endophytic fungi in elms (Ulmus spp.). PLoS ONE, 8(2), e56987. Scholar
  71. Martín, J. A., Sobrino-Plata, J., Rodríguez-Calcerrada, J., Collada, C., & Gil, L. (2018). Breeding and scientific advances in the fight against Dutch elm disease: Will they allow the use of elms in forest restoration? New Forests.
  72. Menkis, A., Östbrant, I.-L., Wågström, K., & Vasaitis, R. (2016). Dutch elm disease on the island of Gotland: Monitoring disease vector and combat measures. Scandinavian Journal of Forest Research, 31(3), 237–241. Scholar
  73. Motiejūnaitė, J., Kutorga, E., Kasparavičius, J., Lygis, V., & Norkutė, G. (2016). New records from Lithuania of fungi alien to Europe. Mycotaxon, 131, 49–60. Scholar
  74. Müller, M. M., Hamberg, L., & Hantula, J. (2016). The susceptibility of European tree species to invasive Asian pathogens: A literature based analysis. Biological Invasions, 18, 2841–2851. Scholar
  75. Paal, J. (1998). Rare and threatened plant communities of Estonia. Biodiversity and Conservation, 7, 1027–1049. Scholar
  76. Phillips, D. H., & Burdekin, D. A. (1992). Diseases of forest and ornamental trees (pp. 299–314). London, Basingstoke: Palgrave Macmillan.CrossRefGoogle Scholar
  77. Pinon, J., Husson, C., & Collin, E. (2005). Susceptibility of native French elm clones to Ophiostoma novo-ulmi. Annals of Forest Science, 62, 689–696. Scholar
  78. Pipe, N. D., Buck, K. W., & Brasier, C. M. (1997). Comparison of the cerato-ulmin (cu) gene sequences of the Himalayan Dutch elm disease fungus Ophiostoma himal-ulmi with those of O. ulmi and O. novo-ulmi suggests that the cu gene of O. novo-ulmi is unlikely to have been acquired recently from O. himal-ulmi. Mycological Research, 101(4), 415–421.CrossRefGoogle Scholar
  79. Pitney Bowes Software. (2015). MapInfo Pro Version 15.0.Google Scholar
  80. Raudsaar, M., Pärt, E., & Adermann, V. (2016). Volume of tree species in forest land. In Yearbook Forest 2014, 5, Keskkonnaagentuur (ed.) (p. 20).Google Scholar
  81. Rist, E. (2015). Tihemetsa pargi inventuur (Inventory of Tihemetsa park) [in Estonian]. Tihemetsa: Lõputöö.Google Scholar
  82. Rosenvald, R., Drenkhan, R., Riit, T., & Lõhmus, A. (2015). Towards silvicultural mitigation of the European ash (Fraxinus excelsior) dieback: The importance of acclimated trees in retention forestry. Canadian Journal of Forest Research, 45(9), 1206–1214. Scholar
  83. Rytkönen, A., Lilja, A., Petäistö, R.-L., & Hantula, J. (2008). Irrigation water and stem lesions on Betula pendula in a forest nursery. Scandinavian Journal of Forest Research, 23, 404–411. Scholar
  84. Rytkönen, A., Lilja, A., Drenkhan, R., Gaitnieks, T., & Hantula, J. (2011). First record of Chalara fraxinea in Finland and genetic variation among isolates sampled from Åland, mainland Finland, Estonia and Latvia. Forest Patholology, 41, 169–174. Scholar
  85. Saarse, L., & Veski, S. (2001). Spread of broad-leaved trees in Estonia. Proceedings of the Estonian Academy of Sciences, Geology, 50(1), 51–65.Google Scholar
  86. Sacchetti, P., Tiberi, R., & Mittempergher, L. (1990). Preference of Scolytus multistriatus Marsham in twig-crotch feeding on two elm species. Redia, 73(2), 347–354.Google Scholar
  87. Santini, A., & Faccoli, M. (2013). Dutch elm disease and elm bark beetles: A century of association. iForest Biogeosciences and Forestry Collection: 3rd International Elm Conference “The elms after 100 years of Dutch Elm disease”, 8, 126-134. (A. Santini, et al., ed.) Florence, Italy.
  88. Santini, A., Pecori, F., Pepori, A. L., Ferrini, F., & Ghelardini, L. (2010). Genotype×environment interaction and growth stability of several elm clones resistant to Dutch elm disease. Forest Ecology and Management, 260, 1017–1025.CrossRefGoogle Scholar
  89. Scheffer, R. J., Voeten, J. W., & Guries, R. P. (2008). Biological control of Dutch Elm disease. Plant Disease, 92(2), 192–200. Scholar
  90. Schmidt, O. (2006). Wood and tree fungi. Biology, damage, protection and use (pp. 168–170). Berlin, Heidelberg: Springer-Verlag.Google Scholar
  91. Solheim, H., Eriksen, R., & Hietala, A. (2011). Dutch elm disease has currently a low incidence on wych elm in Norway. Forest Pathology, 41, 182–188. Scholar
  92. Solla, A., & Gil, L. (2002). Xylem vessel diameter as a factor in resistance of Ulmus minor to Ophiostoma novo-ulmi. Forest Pathology, 32(2), 123–134. Scholar
  93. Solla, A., Bohnens, J., Collin, E., Diamandis, S., Franke, A., Gil, L., et al. (2005). Screening European elms for resistance to Ophiostoma novo-ulmi. Forest Science, 51(2), 134–141. Scholar
  94. Solla, A., Dacasa, M. C., Nasmith, C., Hubbes, M., & Gil, L. (2008). Analysis of Spanish populations of Ophiostoma ulmi and O. novo-ulmi using phenotypic characteristics and RAPD markers. Plant Pathology, 57, 33–44. Scholar
  95. Solla, A., López-Almansa, J., Martín, J., & Gil, L. (2014). Genetic variation and heritability estimates of Ulmus minor and Ulmus pumila hybrids for budburst, growth and tolerance to Ophiostoma novo-ulmi. Biogeosciences and Forestry, 8, 422–430. Scholar
  96. Süda, I. (2006). Jalaka-maltsaürask (Scolytus triarmatus (Eggers, 1912)) – uus üraskiliik Baltikumis (Scolytus triarmatus (Eggers, 1912) – A new bark beetle in the Baltics) [in Estonian]. Metsanduslikud uurimused (Forestry studies), 44, 112–117.Google Scholar
  97. Tamm, H. (2007). Taimestik ja taimkate (Vegetation and plantcover) [in Estonian]. Eesti parkide almanahh (Almanac of Estonian Parks) I. Muinsuskaitseamet, Keskkonnaministeerium (pp. 92-97).Google Scholar
  98. Thor, G., Johansson, P., & Jonsson, M. T. (2010). Lichen diversity and red-listed lichen species relationships with tree species and diameter in wooded meadows. Biodiversity and Conservation, 19, 2307–2328. Scholar
  99. Townsend, A. M. (2000). USDA genetic research on Elms. In C. P. Dunn (Ed.), The Elms (pp. 271–278). Boston: Springer.CrossRefGoogle Scholar
  100. Townsend, A. M., & Douglass, L. W. (2004). Evaluation of elm clones for tolerance to Dutch Elm disease. Journal of Arboriculture, 30(3), 179–184.Google Scholar
  101. Tziros, G. T., Nakopoulou, Z. G., Perlerou, C., & Diamandis, S. (2017) Current status of the Dutch elm disease pathogen populations affecting Ulmus minor in Greece. Forest Pathology. Available online at, last accessed Dec. 31, 2018.
  102. Venturas, M., Lopez, R., Martín, J. A., Gasco, A., & Gil, L. (2014). Heritability of Ulmus minor resistance to Dutch elm disease and its relationship to vessel size, but not to xylem vulnerability to drought. Plant Pathology, 63(3), 500–509.CrossRefGoogle Scholar
  103. Voolma, K., Õunap, H., & Süda, I. (2000). Eesti putukate levikuatlas, 2: Ürasklased – Scolytidae (Distribution maps of Estonian insects, 2: Scolytidae) [in Estonian] (p. 84). Tartu: Eesti Loodusfoto.Google Scholar
  104. Voolma, K., Mandelshtam, M. J., Shcherbakov, A. N., Yakovlev, E. B., Õunap, H., Süda, I., et al. (2004). Distribution and spread of bark beetles (Coleoptera: Scolytidae) around the Gulf of Finland: A comparative study with notes on rare species of Estonia, Finland and North-Western Russia. Entomologica Fennica, 15(4), 198–210.Google Scholar
  105. White, T. J., Bruns, T. D., Lee, S., & Taylor, J. (1990). Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In M. A. Innis, D. H. Gelfand, J. J. Sninsky, & T. J. White (Eds.), PCR protocols: A guide to methods and applications (pp. 315–322). New York: Academic Press.Google Scholar

Copyright information

© Koninklijke Nederlandse Planteziektenkundige Vereniging 2019

Authors and Affiliations

  1. 1.Institute of Forestry and Rural EngineeringEstonian University of Life SciencesTartuEstonia

Personalised recommendations