The MD of Bonnyville has released thousands of Canada Thistle Stem Mining Weevils into areas throughout the municipality.
Janice Boden, assistant agriculture fieldman for the MD, said this is their attempt to rid natural pathways of the thistle, following some resident complaints.
Canada Thistle Stem Mining Weevils are small bugs that only mine in plants directly related to the Canada Thistle.
This means crops, flower beds, and other vegitation will not be affected.
Thistles fall under the Alberta Weed Control Act as noxious plants, with a root system that can extend up to six-metres deep underground and over four-metres horizontaly, making it difficult to remove the plant by hand.
The weed's 1,500 seeds disperse by wind, and can remain in the soil for up to 20-years.
“We have a lot of environmental areas around the lakes where we can't use chemical or mechanical cultivation to control the weeds. Canada Thistle is one of the weeds that we get lots of calls on,” explained Boden. “We had to come up with a way of how we were going to control these weeds.”
The MD decided to conduct a trial using weevils.
The small crafty critters burrow their way into the stems of thistle weeds and lay eggs. Once the eggs have hatched, the weevils consume plant tissue, leaving small holes in the weed for disease to enter and attack the thistle.
“We are doing a trial over by Moose Lake along one of the pathways, which are used as an access by different residents to get to the lake,” said Boden.
The use of weevils to eliminate Canada Thistle has been approved in Canada since 1965.
They coninually breed, but don't have “a population explosion.”
The bugs don't bite, and because they only target thistle weeds, it was the optimal choice for the MD, said Boden.
“One of the things people think is that weevils will eat their house, that they're like a termite. They're not. They eat thistle only, and a couple of close weed relatives to thistle. They won't get into your garden or lawn. They're going to stay in these thistle patches,” Boden explained. “The reason they haven't caught on really well in Canada is because it's a really slow process.”
Weevils are slow moving bugs. Taking-out a 10-metre patch can take up to four-years.
“We don't want this thistle around our lake areas... We're pretty excited about the trial,” said Boden.
