New Brunswick

Fredericton braces for destructive beetle by injecting pesticide into ash trees

The City of Fredericton is spraying ash trees with pesticide this summer to combat an invasive beetle that has already made an appearance in other parts of the province. 

Emerald ash borer hasn't yet arrived, but city crews have already 'inoculated' 21 trees

Mike Glynn, a forester with the City of Fredericton. (Mike Heenan/CBC)

The City of Fredericton is injecting ash trees with an insecticide this summer to combat an invasive beetle that has already made an appearance in other parts of the province.

The emerald ash borer, which has destroyed millions of ash trees in North America, was detected in Edmundston last year and in Oromocto just last week.

The beetle hasn't been found in Fredericton, but Mike Glynn, a forester with the city, said the city has already "inoculated" 21 trees, mostly in Odell and Wilmot parks, in preparation for it.

"That gives us time to react and plan our next move," he said in an interview Monday with Information Morning Fredericton

He said it also gives city staff the chance to familiarize themselves with the process and determine how long it takes to treat a tree.

To apply the pesticide, several holes are drilled into the tree. Then a small white canister carrying the insecticide TreeAzin into the holes. The active ingredient in TreeAzin  is azadirachtin, which is derived from a tree native to India called the Neem tree.

Fredericton has about 10,000 ash trees in Odell Park and about 2,400 along city streets. The numbers don't include ash trees in other city-owned parks or on private property. 

The city has drilled holes in 21 ash trees so it can inject the pesticide TreeAzin. (Mike Heenan/CBC)

How many trees will be injected with TreeAzin has not been decided. It cost an estimated $4,200 to $6,300 to treat the first 21 trees, Glynn said.

"Unfortunately, it's going to come down to dollars and cents to a certain extent, so you really have to prioritize." 

The makers of TreeAzin recommend treating trees every two years.

How Fredericton ash trees are being injected with pesticides to keep invasive beetle away

4 years ago
Duration 1:26
Featured VideoForester Mike Glynn describes the process in which ash trees are injected with pesticides to combat an invasive beetle that has already appeared in Oromocto and Edmundston.

The federal government estimates it will cost municipalities $2 billion over the next 30 years to treat, remove and replace ash trees infested with the emerald ash borer.

Glynn said Fredericton has bolstered its detection ability over the past year by setting up traps to identify where and how many beetles there might be.

Should residents protect their trees?

Although it hasn't been seen in the city, the emerald ash borer may already be present, Glynn said.

"It's a very difficult insect to detect."

Ash trees have limited resistance to stave off the insects, which can kill trees within one to four years of infestation. There also aren't any predators or diseases to keep the population in check. 

"Our entire ash tree inventory is threatened," he said. 

The emerald ash borer has killed millions of ash trees across Canada and the United States. (Minnesota Department of Natural Resources/The Associated Press)

Glynn said residents should look into treating ash trees on their own properties.

"It's better to start treating trees before [the beetle] is present," he said.

"If residential homeowners are interested in protecting their trees, they should be considering that now."

On its own, an emerald ash borer only travels about 400 to 700 metres a year, but with people moving firewood from province to province, the ash borer can travel much farther.  

An emerald ash borer larva is removed from an ash tree in Saugerties, N.Y. The insect effectively cut off tree's circulation and eventually killing the tree. (The Associated Press)

The emerald ash borer is a bright and metallic green insect. It is present from May until late summer.

The beetle lays eggs on the bark of the ash tree. Then, those eggs weave their way inside the ash tree, creating tunnels that vary in shape, including, zigzags and an "S" shape. These tunnels erode the ash tree's ability to feed.

Despite efforts to limit its spread with quarantines and pesticides, the emerald ash borer has already made its way from Manitoba, Ontario, Quebec and into the Atlantic provinces.


  • An earlier version of this story incorrectly named the pesticide being applied to ash trees as triazine, a chemical herbicide. In fact, the city is injecting the trees with TreeAzin, an insecticide derived from the Neem tree.
    Jul 31, 2019 10:32 AM AT


Elizabeth Fraser


Elizabeth Fraser is a reporter/editor with CBC New Brunswick based in Fredericton. She's originally from Manitoba. Story tip?