Emerald Ash Borer

What is EAB?

The emerald ash borer (EAB) is a small invasive green beetle that infests and kills all species of ash (Fraxinus) trees. EAB are native to eastern Asia but were discovered in Michigan and Ontario in 2002. The larvae (shown on the right) of these shiny green beetles tunnel beneath the bark of ash trees and gnaws away at the living tissue of ash trees until the tree eventually dies, usually 2 to 4 years after being infected.

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Not every green bug is an Emerald Ash Borer.

At this time, the city encourages residents to learn more about EAB, its symptoms and its common insect "lookalikes" by visiting the Minnesota Department of Agriculture website and the University of Minnesota Forest Resources Extension website. Below is a side-by-side comparison of an Emerald Ash Borer and the Six-Spotted Tiger Beetle (native insect).

compare eab to tiger beetle

Has the Emerald Ash Borer Arrived in Wayzata?

The Emerald Ash Borer (EAB) has not been discovered in Wayzata yet, but it is likely only a matter of time until this unwelcome guest shows up at our doorstep. However, EAB infestations have been confirmed less than one mile away from Wayzata in Orono.

To see where Emerald Ash Borers have been found in Minnesota, check out the Minnesota Department of Agriculture's EAB Status Map.

Hennepin County under EAB Quarantine

The US and Minnesota Department of Agriculture (MDA) are the lead agencies handling EAB. Per the state EAB Response plan, the city of Wayzata will be notified directly once quarantines are established. Because the insect is so difficult to detect, once EAB is detected in an ash tree, it has likely been in an area for 3 to 5 years.

Left to their own devices, EAB spread at a rate of ½ to 2 miles per year. However, the human spread of firewood and goods has accelerated the rate at which it is establishing in new areas. The mature beetles can fly 2 to 6 miles in its short 3-week life span.

Because of the EAB discovery, Hennepin County has been added to the MDA's list of quarantined counties. The quarantine restricts the movement ash trees, ash limbs and branches, ash stumps and roots, ash logs, ash lumber, ash wood, or ash bark chips from a quarantined county into a non-quarantined county.

In addition, hardwood firewood of any kind (ash, oak, etc.) may not be moved from a quarantined county into a non-quarantine county. More details about the quarantine can be found on the Emerald Ash Borer - Minnesota Quarantine website.

Damage to Ash Population

According to the Minnesota Department of Agriculture (MDA) no evidence to date of resistance against EAB has been found in any native North American ash populations. In areas where EAB has become established in North America, ash tree mortality rates approach 100%. Insecticide treatments are available that can in some situations protect individual trees from EAB attack. The damaging agent is the immature stage, the larvae, of the insect.

Symptoms & Treatment

The larvae kill ash trees as they feed on the living tissue under the bark. Sometimes the symptoms can be very subtle. Contact a local consulting certified arborist for an inspection and treatment options. Timing is crucial to any treatments and trees that are already infested may not survive.

Does the City of Wayzata have a plan to deal with EAB?

The City of Wayzata approved a plan in April 2014 to protect a portion of the City's trees from the invasive Emerald Ash Borer. The City of Wayzata's Emerald ash borer (EAB) management plan dedicates funding to treat "legacy" public ash trees in parks and boulevards, remove others that are in poor condition or become infested, and plant new trees. In 2016, the City removed public ash trees on public right of way in the spring and in the fall will plant with bare root trees.

Read the synopsis of the management plan: City of Wayzata Emerald Ash Borer Management Plan.

Ash Injection Program and Treatment of Private Ash Trees

In preparation of the inevitable arrival of EAB, the City of Wayzata has contracted with Rainbow Treecare to treat public ash trees growing along streets and in parks. A city-wide bulk discount is being offered to Wayzata homeowners for trees on private property that are at least 10" in diameter and in good physical condition.

Residents can take advantage of the City's contract prices to treat ash trees on their private property. Residents will be responsible for the full cost of these private treatments. Residents interested in scheduling a treatment for private ash trees should contact Rainbow Treecare at 952-767-6920 for pricing and scheduling.

Contacting an Arborist

Residents may also contact a certified arborist working for a private company. Most reputable companies employing certified arborists will be familiar with the 2 insecticides available. One is applied as a soil drench, the other is an injection. It is not necessary to remove healthy ash trees at this time. Homeowners may also contact the MDA's "Arrest the Pest" hotline at 651-201-6684 after learning more about the pest.

Ash Tree Removal Guidelines

It is not necessary to remove healthy ash trees at this time, though you should start diversifying the tree species in your yard if you have mostly ash trees now.