Heringocrania Unimaculella
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Susceptibility of different provenances of birch in Iceland to Heringocrania unimaculella Brynja Hrafnkelsdóttir Edda S. Oddsdóttir Icelandic Forest Research Downy birch Betula pubescens • The only native forest forming species in Iceland • Birch forest and woodland covered 25- 40% of Iceland's land area around 870 • Today the cover is about 1.5 % • An important tree species in Icelandic forestry Insect herbivores birch in Iceland • A total of 80 insect pests species are found on woody plants in Iceland • 31 found on birch • 21 native (before 1900) • 10 introduced (after 1900) Introduced insect pests on birch in Iceland from 1900 Scolioneura betuleti 33 Argyresthia goedartella .. Tipula paludosa 31 Iceland in Operophtera brumata Philaenus spumarius 29 birch Epinotia solandriana Otiorhynchus singularis on pests 27 insect Heringocrania unimaculella of 25 number 23 Otiorhyncus ovaturovatus Barypeithes pellucidus Total 21 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year of Introduction Insect herbivores birch in Iceland • Effects vary between insect species and years • No or minor damage: Only visible damage • Moderate damage: Tree growth and vigor • Serios damage: Tree death Introduced invasive insect pests on birch in Iceland from 1900 Scolioneura betuleti Introduced invasive insect pests on birch in Iceland from 1900 Scolioneura betuleti 33 33 Argyresthia goedartella Meindýr..Meindýr.. á á birki birki Tipula paludosa Argyresthia goedartella 31 Tipula paludosa •31•8080 insects insects herbivores herbivores species species on on woody woody plants plants in in Iceland Operophtera brumata Philaenus spumarius Iceland Iceland Operophtera brumata Philaenus spumarius in Iceland 29in Epinotia solandriana •29ThereEpinotia of solandrianaare 30 found on birch Otiorhynchus singularis birch • There of are 30 found on birch Otiorhynchus singularis birch on •on The damage is 27• The damage is 27 pests • Valda mismiklu tjóni pests • Valda mismiklu tjóni • Tree death Heringocrania unimaculella insect 25 • Tree death Heringocrania unimaculella insect of 25 • Tree growth and vigor of • Tree growth and vigor • •OnlyOnly útlitslegur útlitslegur 23 Number 23 Otiorhyncus ovaturovatus Number Barypeithes pellucidus Otiorhyncus ovaturovatus Barypeithes pellucidus 21 211900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year of Introduction Year of Introduction Introduced invasive insect pests on birch in Iceland from 1900 Scolioneura betuleti Introduced invasive insect pests on birch in Iceland from 1900 Scolioneura betuleti 33 33 Argyresthia goedartella Meindýr..Meindýr.. á á birki birki Tipula paludosa Argyresthia goedartella 31 Tipula paludosa •31•8080 insects insects herbivores herbivores species species on on woody woody plants plants in in Iceland Operophtera brumata Philaenus spumarius Iceland Iceland Operophtera brumata Philaenus spumarius in Iceland 29in Epinotia solandriana •29ThereEpinotia of solandrianaare 30 found on birch Otiorhynchus singularis birch • There of are 30 found on birch Otiorhynchus singularis birch on •on The damage is 27• The damage is 27 pests • Valda mismiklu tjóni pests • Valda mismiklu tjóni • Tree death Heringocrania unimaculella insect 25 • Tree death Heringocrania unimaculella insect of 25 • Tree growth and vigor of • Tree growth and vigor • •OnlyOnly útlitslegur útlitslegur 23 Number 23 Otiorhyncus ovaturovatus Number Barypeithes pellucidus Otiorhyncus ovaturovatus Barypeithes pellucidus 21 211900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year of Introduction Year of Introduction Heringocrania unimaculella • Small moth • Larvae feeds inside birch leaves • First recorded in Iceland in 2005 • Since then it´s distribution area has been expanding • 2005 • 2017 • 2019 Distribution observations Heringocrania unimaculella Heringocrania unimaculella • Adult emerge from soil in in spring (early April) • Egg laying occurs right after bud burst • Larvae mines inside of leaf until late June • Causes blotch on leaves that later turn brown as the mining continues – changes appearance • The first leafmining species on birch in Iceland Heringocrania unimaculella (2005) Scolioneura betuleti (2016) Heringocrania unimaculella (2005) ..two leafmining insects on birch in Iceland Scolioneura betuleti (2016) Effects of leafmining on birch • The effect on birch growth and vigor are not known • Is likely affecting the trees photosynthesis abilities • Increase susceptibility to other stresses? • Ecolgical impact on natural systems? Susceptibility of different provenances of birch in Iceland to Heringocrania unimaculella • Started in 2017 • Birch trial in Varmidalur, South Iceland • Planted in 1998 • 42 different provenances measured • 5 blocks • 3150 birch plants • Height of trees and damage on leaves were measured Varmidalur Rating scale 0 → No damage 1 → 1-10% damage 2 → 10-25% damage 0 1 2 3 → 25-50% damage 4 →50-75% damage 5 →75-100% damage 3 4 5 The relationship between damage and mean height 5 R2= 0,443 4 damage damage 3 2 1 Heringocrania unimaculella unimaculella Heringocrania 0 0 50 100 150 200 250 300 350 400 Mean height (cm) • H. unimaculella was first found in Varmidalur in 2017 SambandHeringocrania kembuskemmda unimaculella og hæðar birkis Samband annarra skemmda og hæðar birkis 5 Other insect damage 5 4 4 3 3 2 2 Aðrarlaufskemmdir Other Other insect damage 1 Heringocrania unimacuella damage unimacuella Heringocrania 1 0 0 50 100 150 200 250 300 350 400 0 0 50 100 150 200 250 300 350 400 Height (cm) MeðalhæðHeight (cm) (cm) 311 287 285 270 263 256 244 244 238 236 234 229 227 218 210 207 height 201 195 195 193 Average 192 191 Provenances 188 187 187 186 186 185 183 179 179 178 174 160 146 140 132 124 Damage KvæmiProvenances HeightHæð 2. EmblaEmbla (fyrrv. (fyrrv. Bæjarstaðarskógur) Bæjarstaðarskógur) 311 311 1. Bæjarstaðarskógur,Bæjarstaðarskógur, A-Skaft. A-Skaft. 287 287 3. MógilsáMógilsá (fyrrv. (fyrrv. Bæjarstaðarskógur) Bæjarstaðarskógur) 285 285 7. Þórsmörk,Þórsmörk, Rangárv.s. Rangárv.s. 270 270 4. Núpsstaðaskógur,Núpsstaðaskógur, V-Skaft. V-Skaft. 263 263 41. Hallormsstaður,Hallormsstaður, S-Múlas. S-Múlas. 256 256 10a. Haukadalur, Haukadalur, Árness. Árness. (fv. Bæjarst.)(fv. Bæjarst.)244 244 height Provenances Average ProvenancesKvæmi HeightHæð 26.46. Hrollleifsdalur,Gauksstaðir, Jökuldal Skagafj.s. 124 178 21.47. Teigsskógur,Aðalból, Hrafnkelsdal Barðastr.s. 132 174 50.25. BæjarstaðarúrvalNorðdalur, Strandas. (pl.2000) 140 160 40.40. Egilsstaðaskógur,Egilsstaðaskógur, S -S-Múlas.Múlas. 146 146 25.50. Norðdalur,Bæjarstaðarúrval Strandas. (pl.2000) 160 140 47.21. Aðalból,Teigsskógur, Hrafnkelsdal Barðastr.s. 174 132 46.26. Gauksstaðir,Hrollleifsdalur, Jökuldal Skagafj.s. 178 124 Damage Provenances Damage Average height Significant different Significant Can we explain this different between provenances? • Optimal Oviposition Theory or “preference–performance hypothesis” implies that females undergo a strong selection pressure to choose oviposition sites in an optimal way • “The mother know best” • Fast growing trees with bigger leave area → More food for larvae • Oviposition of Heringocrania unimaculella takes place early in spring, right after bud burst Summary • Since Heringocrania unimaculella was first found in Iceland, its distribution range has been expanding and outbreaks occurred • First findings show that H. unimaculella is attracted to provenances of birch that are fast growing • There was no relationship found between birch height and damage of other Lepidoptera larvae • Plants with early bud burst seems to be more damaged than those with late bud bust • Could be useful information for birch provenances selection in Icelandic forestry in the future Thanks! • Guðmundur Halldórsson • Halldór Sverrisson • Funded by Framleiðnisjóður landbúnaðarins .