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Emerald Ash Borer

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Emerald Ash BorerWhat is the Emerald Ash Borer?

The Emerald Ash Borer (EAB) is an invasive beetle from Asia that has quickly become one of the most destructive and costly forest insects in urban forest history. Adults are small, iridescent green beetles that live outside of trees during the summer months. The larvae are grub, or worm-like, and live underneath the bark of ash trees.

Effects of the EAB

EAB larvae feed on the inner bark of ash trees, which disrupts the tree‘s ability to transport water and nutrients. Once an ash tree is infested, it has almost zero chance of survival and will generally die within one to three year.

Is EAB in St. Louis Park?

In mid-June 2019, the Minnesota Department of Agriculture confirmed the presence of emerald ash borer (EAB) in St. Louis Park. It has also been confirmed in the bordering cities of Minneapolis (2010), Plymouth (2015) and Edina (2018).

Visit the interactive EAB status map to view the most up-to-date information on confirmed locations.

Signs of EAB infestation

Emerald ash borer tree damageSigns that an ESB has infested your ash tree include:

  • Woodpecker damage: Woodpeckers feed on EAB larvae and often reveal infested trees during the winter months. These trees become covered in light-colored "flecking" as woodpeckers remove the outer bark.
  • Bark cracks: EAB larvae tunneling under the bark can cause the bark to split open, revealing s-shaped or curvy tunnels underneath.
  • D-shaped exit holes: Emerging adult beetles chew 1/8-inch, D-shaped exit holes. The holes can be difficult to find because of their small size and frequently high location in the tree.
  • Suckers on tree trunks

For more information on signs of EAB infestation, view the Minnesota Department of Agriculture’s video on evaluating trees for EAB infestation.

How to identify an ash tree

Characteristics of ash trees include:

  • Branches that grow directly across the trunk from each other
  • Leaves are compounded (joined by a stalk or wood stem) and include 5-11 leaflets
  • Leaflets have smooth or finely toothed margins
  • On older trees, the bark is tight and in a diamond-shaped pattern. Younger trees have relatively smooth bark.
  • Seeds are dry and oar-shaped

View the Minnesota Department of Agriculture’s website or ash tree identification guide for more information.

Choices for your ash trees

If you have an ash tree on your property, you can choose to treat the tree or remove it.


St. Louis Park is encouraging residents to treat large, well-placed, healthy private ash trees as part of an EAB treatment program. Treating an ash tree is more cost effective than removal and replacement. It also maintains the tree benefits and value of a mature tree to your property!

St. Louis Park’s discounted EAB treatment program

The City of St. Louis Park has contracted with Rainbow Treecare to treat public ash trees growing along streets and in parks.

As part of this partnership, a citywide discount will be offered through 2020 to St. Louis Park homeowners to treat privately owned trees that are at least 10 inches in diameter and in good physical condition. The citywide bulk discount provides homeowners with an affordable option for managing their ash trees for long-term protection.

For more information about the discount program or to schedule a free consultation, visit the Rainbow Treecare website, email or call 952.767.6920.


To remove a tree from your property, you can hire a tree service company that is licensed by the city. You can also choose to remove it yourself if the tree is small. If you remove it yourself, the wood must be disposed of at the city’s brush drop-off site or in your weekly yard waste collection if under 4 inches in diameter.

Do not remove any ash trees or ash wood from your property without first contacting the city’s natural resources division at 952.924.2699 or

The best time of year to remove an ash tree is between October and May when adult EAB beetles are dormant and not flying.

Note: It is against the law to move any ash tree or portion of it out of EAB-quarantined counties — Hennepin County is a quarantined county. Visit the interactive EAB status map for quarantined areas.

EAB prevention

There are many things you can do to help prevent the spread of EAB.

  • Don't import materials to Minnesota that could harbor EAB, such as ash firewood.
  • Don't move firewood unless it's MDA-certified firewood (look for the MDA certified seal).
  • Remember that it is illegal to move all hardwood firewood outside of EAB quarantine areas.
  • Become knowledgeable about recognizing EAB.
  • Be observant about the condition of your ash trees.
  • If you think you may have EAB contact the natural resources division at 952.924.2562.