Volunteers in the Almaguin Highlands may have a new tool to fight phragmites.
That tool is moths.
Phragmites are described as an aggressive weed known to kill both native plants and some animal species.
See: Battle in war against Phragmites set to take a turn
Since 2018 the Phragmites Working Group Lake Bernard in Sundridge and Strong has been tackling the invasive plant each summer into early fall to eradicate the killer weed from Lake Bernard by 2033.
However, working group chair Marilee Koenderink says it's been challenging.
Phragmites are easily 15 feet tall but another 40 to 60 per cent of the plant is underground, so getting to the root is tough.
Additionally, phragmites spread and establish themselves very easily.
Phragmites are native to Europe.
The killer weeds, known as phragmites australis, were introduced to Ontario during the 1880s by ships navigating the St Lawrence Seaway and then into the Great Lakes by attaching themselves to ships' ballasts.
During the 1990s they began making their way to northern Ontario along Highway 11 by embedding themselves in the wheels of ATVs and construction vehicles.
The weed is now found well beyond Sault Ste. Marie.
Phragmites outcompete native species for water and nutrients.
Their roots release a toxin into the soil which hinders the growth of surrounding plants and kills them.
The weed is extremely harmful to lakes, fish, native plants, turtles, toads, birds and species at risk.
It's considered the most aggressive invasive species in the wetlands of North America.
In Ontario, phragmites have no natural enemies but they do in Europe.
Their natural European enemies are two species of moths, Lenisa geminipuncta and Archanara neurica.
In a presentation to the Strong town council, Koenderink said Dr. Michael McTavish of the University of Toronto heard of the local working group's battle with phragmites and contacted the volunteers indicating he might be able to help.
That help is in the form of a biocontrol program.
That program hopes by introducing the two species of moths to the area with the goal of reintroducing the phragmites to their natural enemies.
Koenderink said McTavish and his research teams would like to set up a nursery in the Lake Bernard area with moth eggs.
When the caterpillars hatch from the eggs they make their way to the phragmites where they would bore into the stems and begin eating.
This would continue until the caterpillars go into their cocoon stage and emerge as moths, and after mating they start the cycle over again on their own.
Koenderink told council McTavish would set up the nursery which cannot be removed and would be monitored and managed by the researchers for four years.
“This is cost-effective for us because it's free, and we don't have to do anything,” Koenderink told the council.
“We'll be bringing the plant and its natural enemy together again and the biocontrol agent (the moths) can help wetlands re-establish a natural balance”.
Koenderink says the biocontrol program is self-sustaining and the moths are not a threat to native plant species.
The researchers have established 13 sites across Southern Ontario that face phragmites issues, and at several locations, the caterpillars have caused visible damage to the plant.
Once the caterpillar bores its way into the phragmites stems and begins feeding, the weed wilts or dies.
Koenderink says the researchers want to expand the biocontrol network by adding a nursery at Lake Bernard.
She says if it agrees to the proposal, the Strong Council will have to identify the site.
“We're seeing the size of our (phragmites) stands going down, but this is another tool that will take hold and spread and speed up the (eradication) process,” Koenderink told the town council.
Members of Council liked the proposal and directed staff to come back with a report to identify a site for the biocontrol program.
Rocco Frangione is a Local Journalism Initiative reporter who works out of the North Bay Nugget. The Local Journalism Initiative is funded by the Government of Canada.
