Successful program controls noxious weeds
Lois E. Johnson
Monica Chandler of the Minnesota Department of Agriculture and Greg Bernu, Carlton County Land Commissioner, examine a larvae and how it can bury itself into a taproot of a knapweed plant.
The success of a program to control noxious weeds in Carlton County was surveyed on Thursday, July 25, when a representative from the Minnesota Department of Agriculture and staff from many different counties and governmental units met at the Moose Lake-Carlton County Airport.
Carlton County Land Commissioner Greg Bernu brought in certain types of beetles and weevils to control Spotted Knapweed and Leafy Spurge on the airport grounds in 2009, where it had flourished and spread for many years. The insects had been first introduced to the area in 2003.
“It was a good chance for everyone to see what bio-control looks like,” said Bernu. “Spotted Knapweed and Leafy Spurge can take over rangeland very quickly. These insects are very specific to control these weeds.”
Bernu explained that green beetles attack the flower heads on the Spotted Knapweeds, and it feeds on the roots during the winter, when it is in the larval stage. The beetle lays its eggs at the root collar, and the larvae burrows into the tap root.
Tiny seed-head weevils, about the size of a deer tick, attack the flowers on Leafy Spurge. They also attack the root collars of the spurge.
Bernu is pleased with how well the insects have controlled the weeds. As he showed an open area on the east side of the airport, the yellow and purple flowers of the two noxious weeds dotted the landscape in patches.
“This area used to be just covered with these weeds,” he said. “Now it is considered controlled. There is such a success story with it that the state is excited.”
Monica Chandler of the Minnesota Department of Agriculture said, “Some states spend $42 million a year to control Spotted Knapweed. It flourishes on a lot of grazing land. Elk won’t go where there is Spotted Knapweed.
“Anyone can go out and check to see if they have either one or both of these weeds. If a landowner has these weeds, call Greg to find out how to control them. I think everyone will see these weeds around.”
The Spotted Knapweed is a plant that grows to be a foot high, and it has gray green leaves with a lilac-colored flower that resembles a thistle flower.
The Leafy Spurge is about a foot high, with clusters of yellow flowers.
For more information, call Greg Bernu, the Land Commissioner for Carlton County at (218) 384-9179.