Ash Trees: They have problems

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Ash Trees They have problems!

• Laura Jesse
• Plant Insect Diagnostic Clinic
• Iowa State University

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Ash anthracnose

• Fungal leaf disease
• Can cause leaf drop

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Ash anthracnose

• Brown lesions on leaves
• Curled distorted leaves
• Management
• Rake up fallen leaves
• Fungicides rarely needed

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Verticillium Wilt

• Fungal disease that affects many tree species
• Symptoms appears in June - July
• Sudden wilting of leaves on one or several twigs
• Branch or crown eventually wilts
• Decline or dieback of new twigs
• Yellowing foliage
• Sapwood discoloration
• More common on stressed trees
• Management Remove infected trees

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Ash Decline

• Observed since 1930s
• Primarily white and green ash
• Unexplained progressive decline

http//www.colostate.edu/Dept/CoopExt/4DMG/images/
decline.jpg
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Ash / Lilac Borer
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Ash/lilac Borer

• Symptoms
• Exit holes
• Sawdust and frass
• Swelling and cracking
• Management
• How extensive is the damage
• Three insecticide treatments starting mid-May
• Pheromone traps available

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Other Borers

• Longhorned beetles
• Redheaded ash borer
• Banded ash borer

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• Roundheaded borers

• Emerald ash borer

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Other borers

• Eastern ash bark beetle

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1) Do you know the tree(s) are ash, Fraxinus
species?
Client Reporting a Stressed Ash Tree
http//www.extension.iastate.edu/pages/tree/key.ht
ml
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http//emeraldashborer.info/files/E2942.pdf
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2) Does the tree have thinning crown? Are
branches dying?

• How old is the tree?
• How long has client observed the problem
• Several years or very recently
• Age of tree
• Appearance of individual leaves

http//www.snr.missouri.edu/images/forestry/emeral
dash/thin-canopy.jpg
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3) Are there suckers / watersprouts growths on
the trunk?
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4) Are woodpeckers working on the tree?
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• Are there S-shaped feeding galleries under the
  bark? Near top of tree

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4) Loose bark with S-shaped feeding galleries
under the bark? Starts near top of tree.
Credit M. H. Shour, ISU Extension
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5) Are there D-shaped exit holes (1/8th inch
diameter)?
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If you cannot eliminate EAB as a possibility or
client wants a diagnosis

• Send samples to
• Plant Insect Diagnostic Clinic
• 327 Bessey Hall
• Ames, IA 50011
• Send digital images of the tree to
  insects_at_iastate.edu

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Client reports they have caught an adult beetle

• EAB is most likely to be detected in an ash tree
  in the larval stage. However, many reports will
  involve a client seeing suspected adults.
• If the client has not collected a specimen
• Show them pictures of look-alike insects to see
  if they think maybe it was something besides an
  EAB.
• Ask them to try to capture a specimen next time
  they see one.

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http//www.extension.umn.edu/distribution/horticul
ture/M1242.html
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• If the citizen has the insect
• Mail the insect to
• Plant Insect Diagnostic Clinic
• 327 Bessey Hall
• Ames, IA 50011
• E-mail pictures to
• insects_at_iastate.edu

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Thank You!

• Plant Insect Diagnostic Clinic
• 327 Bessey Hall
• Ames, IA 50011
• 515/294-0581
• insects_at_iastate.edu
• ljesse_at_iastate.edu