Emerald ash borer an invasive beetle that can devastate ash tree populations has recently been discovered in Gravenhurst and Bracebridge after a long-term program in which traps were set up to capture signs of the insect’s presence. /Submitted photo

Invasive beetle found in neighbouring areas

By Sue Tiffin

Published Nov. 27 2018

The presence of the emerald ash borer hasn’t been confirmed in Haliburton yet but the invasive wood-boring beetle has been identified in Muskoka and City of Kawartha Lakes and it’s just a matter of time before the insect establishes itself here.

The emerald ash borer native to Asia is a small beetle with a metallic green back and emerald green underside. It’s believed to have crossed into Ontario at Windsor from the Detroit area where it might have arrived in wood packaging or pallets. The Canadian Food Inspection Agency calls it “highly destructive” as it attacks and kills all species of ash and is already responsible for killing millions of trees in North America.

Infestations now exist across much of southern Ontario according to the provincial government’s information page about the insect from Lambton County north to Grey County and east to Renfrew County and Ottawa. It’s also been found on Manitoulin Island and in Sault Ste. Marie. The emerald ash borer was confirmed to be in Fenelon Falls in 2013 and just this past September in Bracebridge and Gravenhurst.

“We’ve been running this program for four years now and we’ve just got our first sighting this year of them” said Aaron Rusak program co-ordinator at Muskoka Conservancy. The Muskoka Conservancy had been working with Bioforest Technologies as well as the cities of Bracebridge and Gravenhurst to monitor possible emerald ash borer infestation in the region using traps set up in area nature reserves on town property and in areas offered by volunteer residents.

“The emerald ash borer causes over 90 per cent mortality in ash trees it infects so it kills almost entire ash populations” said Rusak. “The worry mainly is that … we have a lot of urban ash so ash that has been planted in urban areas because it’s a hearty tree. The worry is that it kills those and then there’s cost for the towns for either removal of the tree or cleaning up of the waste and then replanting. So there’s concerns about it in the urban setting. But there’s also concerns about it in the natural setting where it survives really well on shorelines and things like that so it’s used as a shoreline stabilizer and if we suddenly lose that you see that potentially impacts on the shoreline as well. Essentially the main concern is that we lose all of our ash … it pretty much wipes out the tree populations wherever you find emerald ash borer.”

Emerald ash borer (Agrilus planipennis) feeds on all ash (Fraxinus) species in Ontario as well as some non-native species such as European black ash. Mountain ash is safe as it’s actually a different species of tree.

Dan Rowlinson co-ordinator of Ontario Forest Health Monitoring provincial services division biodiversity and monitoring section Ministry of Natural Resources and Forestry said annual surveys for emerald ash borer presence occur in July.

“We fly annually and detect disturbances from the air on grid pattern searches” he told the Echo. “If we see ash that are dying or declining we do ground verification to just confirm or deny if it is in fact emerald ash borer.”

Because of its small hard-to-spot size it’s possible that the emerald ash borer might be detected not by being spotted itself but due to the serpentine or S-shaped lines formed underneath bark by larva or by the actual presence of destroyed ash trees.

The lines left by the larva disrupt the natural nutrients and water transport system which can leave what was a healthy tree dead in two to five years.

Signs of an infestation include chlorosis or the loss of green colour in the uppermost leaves of ash trees and thinning and dieback of the crown according to the Canadian Food Inspection Agency website.

Adult beetles emerge from infested trees in May fly to the next ash tree and the cycle repeats.

Catching signs of the beetle early is ideal.

“That’s what the project was designed to do” said Rusak. “It was designed to catch it early so that we have time to prepare our response. In that sense it’s succeeded. It’s bad news that we have the bug but it’s good news that we have the project and were able to catch it early on.”

Now that their traps have shown signs of the insect the Muskoka Conservancy has a plan.

“From there we’re working with the towns to go toward the next steps: potentially continuing monitoring a management plan being drafted a decision being made about what’s next whether we’re treating some of the trees treating all of the trees whether we’re letting the bug just take its course…” said Rusak. “The decision ultimately comes down to the town but we’re partnering with them and helping them make that decision we’re providing any assistance we have or any contacts we’ve made through this program.”

“Early detection is probably the best opportunity to prevent it” said Rowlinson. “It’s gonna come. It’s going to come there eventually. But early detection gives you better opportunity to control it on things like ornamental type trees. And also when you’re planting trees in your yards or on your property or even in your towns or communities it’s good to visit the [Ontario.ca] website and get a list of non-preferred host trees. Instead of planting green and white ash on your boulevard type trees move to something like the basswoods something like that that isn’t as attractive to some of the pests out there.”

Rowlinson said there’s much research happening now to help with population control when the invasive species is found.

“I always use gypsy moth as a good example” he said. “It was introduced into Ontario in the ’80s and we thought it was going to be the demise of our oak trees on the landscape. It’s been around long enough now that the parasites the diseases have built up within that population. I’m not saying scientifically that’s going to happen with the emerald ash borer but we do have a good example of the gypsy moth that it has happened in the past.”

Locally emerald ash borer hasn’t been found but its existence has been monitored.

“We have been monitoring for emerald ash borer at Haliburton Forest for more than five years but we haven’t found anything yet” said Malcolm Cockwell managing director of Haliburton Forest who said that at one point professional researchers were doing some of the monitoring work. “However in anticipation of its arrival we have modified our forest management practices with the various ash species that grow in our area.”

Cockwell said that in his own relatively short career as a forester he had already seen thousands of acres devastated by beech bark disease.

“Invasive species are a major and ongoing concern” he wrote in an email to the Echo. “I do believe that invasive species pose a greater threat to our natural environment than any other anthropogenic impact.”

To prevent the spread of emerald ash borer the message from every organization and agency is consistent: don’t move firewood.

“Our main message to the public in regards to reducing the impacts of all forest pests is ‘don’t import firewood – buy locally’” said James Rogers forest conservation officer with the County of Haliburton.

“To prevent the spread of invasive species it is critical that visitors and residents alike limit the movement of wood from southern Ontario into Haliburton County” said Cockwell. “It is also good practice to wash off boats as well as ATVs and mountain bikes when riding in different areas.”

“The big message we get out there is that moving wood products from infested areas to uninfested areas is probably one of the number one ways it does get spread around” said Rowlinson.

Rusak cited a map showing the current presence and movement patterns of emerald ash borer.

“The bug can move up to 10 kilometres a year naturally but often it’ll move from one ash tree to the next ash tree so its movement is basically tree to tree however if the ash tree is cut down and the larva are in the bark and the larva are carried to a campsite or something that’s potentially a spread of the bug” he said.

“So a lot of its movement is through infected lumber and that’s why you see things popping up in Manitoba and Nova Scotia … where there’s been none sighted ever and the closest one is Quebec that it’s been sighted and that would be due to infected lumber. It doesn’t just suddenly appear there …Where it is you can see on the map there’s a jump from Montana to Colorado basically and that’s mainly due to this movement of infected lumber” he said.

Moving ash material and any type of firewood from specific areas of Manitoba Ontario Quebec New Brunswick and Nova Scotia is federally prohibited and subject to fines or prosecution.

For more information visit ontario.ca/page/emerald-ash-borer.