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Parks and Open Space

Emerald Ash Borer (EAB)

Emerald Ash Borer

Emerald ash borer (EAB) is an invasive wood-boring insect that was introduced into North America from China and eastern Asia. EAB attacks and kills healthy and stressed ash trees. All ash species are susceptible in varying degrees. EAB was recently detected in Winnipeg. Once detected, it cannot be eradicated.

The City is currently finalizing its EAB response and management plans. A report for City Council's consideration outlining a recommended management approach and associated costs will be coming forward in the new year. The goal is to spread out the mortality of ash trees over time to allow more proactive management of tree removals and replacements, and to preserve our healthy ash trees for as long as possible.

FAQ

Q. What is EAB and what does it do to our trees?

A. EAB is an invasive pest introduced into North America from China. It feeds on and kills ash trees whether they are healthy or stressed. It is the larval stage of the beetle that kills the tree. The larvae feed on the tissue underneath the bark. The larval feeding girdles the tree, cutting off the flow of nutrients and water causing the tree to die.

Q. Does EAB attack all trees?

A. EAB attacks only ash trees of Fraxinus genus. All ash species are susceptible in varying degrees. Mountain ash is not an ash tree.

Q. Is the EAB beetle in Manitoba?

A. Yes, EAB has now been detected in Winnipeg. Once detected, it cannot be eradicated. We are currently working with our partners to determine the extent of the spread within the city.

Q. What effect will the EAB beetle have on Winnipeg?

A. The City of Winnipeg is at risk to lose all of its ash trees over a 10-year period, resulting in a loss of at least 30% of our boulevard and park trees valued at approximately $437 million. Many ash trees on private property are also at risk of becoming infected over the next decade.

Q. How did EAB get to Winnipeg?

A. It would be difficult to determine how EAB arrived in Winnipeg. EAB is spread mainly by people moving firewood, nursery stock, trees, logs, lumber, wood or bark chips. All these forms of wood can contain EAB larvae. The beetle can also fly several kilometers.

Q. What can be done?

A. The City has been preparing for EAB for over a decade. We are currently finalizing our EAB response and management plans. A report for Council's consideration outlining a recommended management approach and associated costs will be coming forward early 2018.

One option that will be considered is injecting a percentage of eligible ash trees on public properties with a botanical pesticide to preserve them as long as possible. The remaining ash trees on public properties would be removed as they die and possibly replaced over time. The goal is to spread out the mortality of ash trees over time to allow more proactive management of tree removals and replacements, and to preserve our healthy ash trees for as long as possible.

Q. What has the City done to prepare for EAB?

A. The City's Urban Forestry Branch has been preparing for EAB for over a decade by:

  • creating a public tree inventory and private ash tree inventory
  • initiating discussion within industry including working with the nursery industry to increase the diversity of nursery stock,
  • educating and training staff and industry,
  • monitoring for EAB in partnership with Trees Winnipeg and CFIA using green sticky prism traps,
  • establishing diversity guidelines for the City's reforestation program and new developments,
  • partnering with the Province of Manitoba and CFIA to develop a Manitoba EAB Preparedness Plan, and
  • removing ash species from its reforestation program.

Q. Do other places in Canada have EAB?

A. Yes, the beetle is currently in northwestern and southwestern Ontario, southern Quebec, and in 29 states in the United States, including Minnesota and is now in Winnipeg.

Q. What can I do to prevent the spread of EAB?

A. You can help prevent the spread of EAB:

  • Don't move firewood,
  • Burn firewood where you buy it,
  • Plant a variety of tree species to increase diversity,
  • Learn how to identify an ash tree, and
  • Learn how to identify the signs and symptoms of EAB

Q. What does EAB damage look like?

A. Signs of EAB include:

  • D-shaped exit holes in the bark,
  • excessive wood pecker feeding
  • foliar feeding by the adult beetles during the summer, creating irregular notches in the leaves,
  • "S"-shaped larval tunnels underneath the bark (cannot be readily seen on the exterior of the tree),
  • presence of larvae underneath the bark, and
  • bark splitting where larval tunnels occur underneath the bark.

Trees infected with EAB may not show symptoms for two to four years upon initial infestation. Symptoms include:

  • general decline and dieback in the tree crown, and
  • suckering of your shoots in the lower trunk of the tree.

Q. What does the emerald ash borer look like?

A. Adult beetles are metallic green, narrow, hairless and approximately 1.25 cm or 1/2 inch long and .3 cm or 1/8 inch wide. Mature larvae are approximately 2.4 cm or 1 inch long and creamy white. The body is flat, broad shaped and segmented.

Q. What should I do if I think my tree has EAB?

A. If you think you have found an emerald ash borer you should:

  • Record the location of the tree,
  • Record the signs and symptoms you observed,
  • Collect an adult specimen, keep it in a container in a freezer (to preserve it), and
  • Call 311 or contact the Canadian Food Inspection Agency or call the Emerald Ash Borer hotline at 1-866-463-6017.

Q. Who regulates the management of EAB?

A. Prevention, response to and management of EAB are regulated federally by the Canadian Food Inspection Agency (CFIA) under the authority of the Plant Protection Act and Regulations, and provincially under the authority of the Forest Health Protection Act and Regulations. The City of Winnipeg is mandated to manage EAB in accordance with federal and provincial legislation.

Adult BeetleEAB

EAB Larvae

More information

More detailed information on EAB is available on the following websites:

Canadian Forest Service (CFS) has also released a publication entitled A Visual Guide to Detecting Emerald Ash Borer Damage. This publication is available at no charge by calling CFS, Great Lakes Forestry Centre at (705) 949-9461. It can also be ordered online at the following website:
http://cfs.nrcan.gc.ca/publications?id=26856. It is available in English or French.


Last update: December 8, 2017