The situation of elms and Dutch Elm disease in Estonia LIINA JÜRISOO & REIN DRENKHAN LUKE, Helsinki 14.11.2019 Elms in Estonia • 0,1 % of the total volume of forest trees • Ulmus glabra is spread scarcely allover Estonia • Ulmus laevis is much rarely, mostly next to the rivers • common and valuable amenity trees Ulmus laevis fall colour RESISTA® ‘New Horizon’ 2016 planted in Narva 2015 Euroroute R1 From France to St. Petersburg RESISTA® ‘New Horizon’ 2019 Tartu Elms’ health •Significantly worse since 2013 in Tallinn •Relatively better in other regions •Comparison of the vitality of Ulmus glabra during 24 months, in 2014 and 2016. Locations of sampling sites Tallinn 1225 trees; 109 repetitively Monitoring the health status of elms 1 2 3 4 5 Vitality classes Health of Ulmus spp. Probability of changing of vitality 5 4 2016 3 class 2 Vitality A1+B1 A1 B1 1 1 2 3 4 5 Vitality class 2014 Relative incidence of symptoms of DED depending on vitality class Ulmus glabra+ U. laevis Symptoms of DED yellowing flagging compartmentalisation tylosis Dead elms in Vana-Vastseliina South-East Estonia DED in Estonia registered already in 1930-s (Lepik, 1940) Ophiostoma ulmi DED pathogens in Estonia • Ophiostoma ulmi is reported in EPPO lists since 1979 • 2000 – unsubstantial in Mycobiota of Estonia (ed. K. Kalamees) • O. novo-ulmi – identified in 2006 by M. Hanso Identification of the pathogen species • DNA was extracted from isolations • The pathogen confirmation was done by ITS sequencing Ophiostoma novo-ulmi Identification of subspecies • Gene col1 species-specific primed PCR (Konrad et al. 2002) • Ophiostoma novo-ulmi subsp. novo-ulmi • Ophiostoma novo-ulmi subsp. americana • Difference in 6 nucleotides between the subspecies Identification of hybrids • The cu gene region was amplified with the primers (Pipe et al. 1997) • Digested by restriction enzyme Hph I • The PCR products were visualized on 1% agarose gels under UV light Ophiostoma novo-ulmi hybrids in Estonia? Gene col1 Gene cu subsp. novo-ulmi subsp. novo-ulmi subsp. americana subsp. americana NO HYBRIDS Ophiostoma novo-ulmi subsp. in sampling sites Tallinn subsp. americana Tartu subsp. novo-ulmi Conclusions (Estonia) • For the first time Ophiostoma novo-ulmi with its both subspecies: • subsp. novo-ulmi • subsp. americana • DED is more devastating to Ulmus glabra than to U. laevis. Conclusions 2 (Estonia) • O. novo-ulmi subsp. americana demonstrated higher aggressiveness towards elms, its victims died 2 times faster than ones infected by O. novo- ulmi subsp. novo-ulmi. • the mean probability of elm trees to die for DED was 20.4% per year. ARTICLE Health of elms and Dutch elm disease in Estonia Saint Petersburg Leningrad Region DED pathogens in Russia • In west regions of USSR and South-West of Asia in 1936 – Ophiostoma ulmi • Ophiostoma ulmi - reported in EPPO lists since 1979 Health of elms in St. Petersburg • worsened substantially since 1995 YEAR Afflicted plots 2002 29 2006 42 2007 76 2015 700 • In 2015, 5000< dead elms were cut down Some bacground • Since 2006, Resista elms had been planted in several parks and alleys in Saint Petersburg. • Ulmus davidiana var. japonica × U. pumila ‘New Horizon’ • U. glabra `Exoniensis' x U. wallichiana 'Dodoens' Sampling plots in Russia Assessed 683 trees in 2016 • Ulmus glabra • Ulmus laevis • Ulmus spp. • ’New Horison’ (Ulmus japonica x U. pumila) • ‘Dodoens’ (U. glabra `Exoniensis' x U. wallichiana) DED agents in Russia • Ophiostoma novo-ulmi subsp. • novo-ulmi • americana • novo-ulmi x americana • americana x novo-ulmi Diameter , cm 9 am x nu 8 nu x am 7 am 6 nu 5 4 3 2 1 0 0 5 10 Time, day Vectors of the pathogen in Estonia in Saint-Petersburg • Scolytus scolytus • Scolytus scolytus • S. multistriatus • S. multistriatus • S. triarmatus • S. pygmaeus Scolytus Entry holes “Patterns” of Scolytus larvae Hummuli, Estonia Ulmus laevis in St. Petersburg (2019) Collected samples 2019 in Estonia 2018 2019 New records in 2019 ACKNOWLEDGEMENTS • Supervisor – prof. Rein Drenkhan • Co-authors – dr Kalev Adamson, Allar Padari • Advisor – dr Märt Hanso • Everybody, who helped to collect the data and samples Research is supported by grants PSG136 IUT21-04 SHORT SCIENTIFIC VISITS ‘Camperdownii’.