Emerald Ash Borer

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Emerald Ash BorerWhat is EAB?

EAB stands for emerald ash borer. It is an insect that attacks and kills all species of ash trees that grow in Minnesota. The beetle is a small (less than ½ inch) iridescent green bug that feeds on ash trees during the summer. It lays eggs underneath the bark and as the eggs develop into larvae they feed on the cambium underneath the bark denying the tree the nutrients it needs to survive. Ultimately the tree dies over a two to three year period.

Symptoms of EAB Infestation

  • Crown dieback from the top
  • New epicormic (the lower trunk) shoots or growth
  • D-shaped exit holes
  • Bark splitting
  • S-shaped or serpentine shaped galleries formed under the bark
  • Extensive woodpecker damage


On April 4th, 2017 the Parks & Recreation Committee of Council (Braucks*, Folch, Leifeld) met and discussed boulevard tree maintenance requirements.  The meeting's packet materials provide background along with current ordinance and policies.  The meeting follow up summarizes the Committee's action.

On May 1st, 2017 the City Council discussed and adopted the boulevard tree maintenance recommendation forwarded by the Parks & Recreation Committee of Council.  Parks & Recreation Director, Chris Jenkins also provided a brief presentation related to EAB including a map of ash trees in boulevards.

What can be done?

  • Positively identify trees and have them professionally evaluated.
  • Proactively treat ash trees with insecticides.
    • Professional tree care services offer injection treatments.
    • Property owners can purchase and apply soil drench insecticides.  Follow the instructions on the label, it is the law.
    • If you treat a boulevard tree, save your receipts!
  • Tree removals effectively eliminate EAB's food source.D-Shaped Exit Hole
    • Trees on private property can be removed at any time and does not require coordination with the City Forester.
    • Removal of trees within boulevard spaces must be authorized by the City Forester, and the removal must be done through a licensed tree removal service.
  • Monitor the condition of all trees on your property, keep an eye out for damage and pests.

What is the City going to do?

  •  A complete boulevard and park tree inventory has been completed.
    • Approximately 1,000 ash trees are within boulevard spaces, this represents 22% of all boulevard trees.
    • Approximately 500 desirable ash trees exist with parks and open spaces.
  • The City Forester will be treating ash trees within parks and open spaces beginning in 2017.
    • The approved treatment plan will treat 1/3rd of the ash trees each year.
    • The treatment plan is anticipated to run for 10 years.
  • The City will work with professional tree care services in hopes of establishing a "not to exceed" price per inch for treating ash trees in Hastings.
    • The agreements will require willing participants.
    • The agreements will allow residents to take advantage of lower treatment costs for boulevard and private property ash trees.
  • The City will continue to communicate with residents on City efforts and the importance of proactive/preventative control efforts.

What else?

  • S-Shaped Galleries Under the BarkDo not buy or move firewood if you do not know its identity or source. Movement of infested wood has been the most prevalent way of transporting the pests from infested to uninfested areas.
  • Avoid pruning Ash trees until late fall or winter when trees are dormant.
  • Look for the symptoms of EAB in Ash trees and if you have questions or concerns, contact the City Forester, Paul Mahoney, at 651-480-6177 or call a tree care professional.