Forest Invasive Species

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Emerald Ash Borer Question & Answer

What is Emerald Ash Borer?

Emerald ash borer (EAB), Agrilus planipennis, is a highly destructive invasive wood boring beetle that kills ash trees when the larvae (caterpillars) feed in the nutrient conducting vessels of the trees. First detected in Ontario and Michigan in 2002, Emerald Ash Borer was likely introduced to North America through ash packing material used in shipments from China.

What does Emerald Ash Borer look like?

The adult beetle is dark metallic green in colour and about 1.0 centimetre long.

Where has Emerald Ash Borer been found?

Emerald Ash Borer can be found in Ontario, Quebec and a number of states in the USA. In November of 2017, Emerald Ash Borer was found for the first time in Manitoba, in Winnipeg. At this time, it has not been found in any other Manitoba locations.

What trees will Emerald Ash Borer attack?

Emerald Ash Borer attacks and kills ash trees. (Showy mountain ash is not a true ash and is not vulnerable to Emerald Ash Borer.)

What is the problem with Emerald Ash Borer?

Emerald ash borer is an invasive forest pest that has killed billions of ash trees in North America causing serious environmental and economic impacts. At low levels Emerald Ash Borer is hard to detect, but after the population builds, ash trees start dying.

Ash trees have been widely planted in Manitoba communities as a replacement for elms lost to Dutch elm disease and are a major component of many urban forests. Ash trees have also been planted in rural shelterbelts and grow here naturally in riverbank areas.

How is Emerald Ash Borer different from Dutch elm disease (DED)?

DED is a fungus that is spread by the native elm bark beetle. The beetle itself does not harm the tree. Ash trees affected by Emerald Ash Borer die as a direct result of larval feeding under the bark of the tree.

Unlike trees affected by DED, which can usually be noticed in the first year of infection through visual surveys, Emerald Ash Borer is initially difficult to detect. If a tree is confirmed to have Emerald Ash Borer there is a high probability that neighboring trees are also affected even if the tree appears to be healthy.

How does Emerald Ash Borer spread?

While Emerald Ash Borer will spread naturally, it is spread faster through the movement of infested ash material, such as firewood and nursery stock, into un-infested areas.

What is being done about Emerald Ash Borer?

The City of Winnipeg is working with the Manitoba government and the Canadian Food Inspection Agency (CFIA) to determine the extent of the infestation and to slow the spread of this damaging pest.

Initial steps taken will include:

How do I identify an ash tree?

Green and black ash are native to Manitoba. Manchurian ash/hybrids have also been planted in Manitoba.

What are the signs and symptoms of Emerald Ash Borer in a tree?

How can I protect my ash trees?

Insecticides are available to protect trees from Emerald Ash Borer. As treatments can be somewhat damaging to the tree, it is not recommended that you treat your ash trees until Emerald Ash Borer is found in your community or nearby. It is recommended that you get quotes from several tree care companies when seeking treatment options. All pesticide applications must be completed by a licensed pesticide applicator.

If my tree is confirmed to have Emerald Ash Borer what are my options?

Current options available include tree removal or insecticide application. It is recommended that you get quotes from several tree care companies when seeking removal and/or insecticide options. All pesticide applications must be completed by a licensed pesticide applicator.

What if I do nothing about Emerald Ash Borer affected trees on my property?

Ash trees affected by Emerald Ash Borer die in one to five years. While in some situations having a standing dead tree can provide wildlife habitat, in an urban environment dead trees can fall, potentially causing personal injury or property damage. Trees killed by Emerald Ash Borer dry out very fast when not removed right away, which can make removal more difficult and costly.

How can I help slow the spread of Emerald Ash Borer in Manitoba?

Be vigilant. Learn about the signs and symptoms of Emerald Ash Borer and report symptomatic ash trees or ash tree products to the Go Wild Manitoba App or Manitoba Sustainable Development's tree line at 204 945-7866 or by email treeline@gov.mb.ca

If you are within the city of Winnipeg please call 311.

More information on Emerald Ash Borer can be found at: