Heringocrania Unimaculella

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

birch Epinotia solandriana Otiorhynchus singularis on

pests 27

insect Heringocrania unimaculella

of 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 of 25 • Tree growth and vigor of 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

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

damage damage

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 insectdamage 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) Provenances Damage

Average height 192 193 195 195 201 207 210 218 227 229 234 236 238 244 244 256 263 270 285 287 311 124 132 140 146 160 174 178 179 179 183 185 186 186 187 187 188 191 Provenances Damage

Average height 46. Gauksstaðir, Jökuldal Hrafnkelsdal47. Aðalból, 25. Norðdalur,Strandas. 40. Egilsstaðaskógur, S 50. Bæjarstaðarúrval (pl.2000) 21. Teigsskógur, Barðastr.s. 26. Hrollleifsdalur,Skagafj.s. Provenances 10a. Haukadalur, (fv. Árness. Bæjarst.) 41. Hallormsstaður, S-Múlas. 4. Núpsstaðaskógur, V-Skaft. 7. Þórsmörk, Rangárv.s. 3. Mógilsá (fyrrv. Bæjarstaðarskógur) 1. Bæjarstaðarskógur, A-Skaft. 2. Embla (fyrrv. Bæjarstaðarskógur) Kvæmi 10a. Haukadalur, (fv.Árness. Bæjarst.) Hallormsstaður,41. S 4. Núpsstaðaskógur, V 7. Þórsmörk,Rangárv.s. 3. Mógilsá (fyrrv.Bæjarstaðarskógur) 1. Bæjarstaðarskógur,A (fyrrv.2. Embla Bæjarstaðarskógur) Provenances 26. Hrollleifsdalur, Skagafj.s. 21. Teigsskógur, Barðastr.s. 50. Bæjarstaðarúrval (pl.2000) 40. Egilsstaðaskógur, S-Múlas. 25. Norðdalur, Strandas. 47. Aðalból, Hrafnkelsdal 46. Gauksstaðir, Jökuldal Kvæmi - Múlas. - Skaft. - Skaft. - Múlas. 178 174 160 146 140 132 124 Height 244 256 263 270 285 287 311 Height Hæð Hæð 124 132 140 146 160 174 178 244 256 263 270 285 287 311 Provenances Damage

Average height Significantdifferent 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