Beetles battle county’s noxious weeds

Milaca – As the Mille Lacs County Board discussed the agricultural management plan for 2017 at its April 4 meeting, talk turned to the use of “biological controls” for noxious weeds, in a word – beetles. While the county has used them for years, it will begin to test how effective they are for weed control in public rights of way.
County Soil and Water Conservation District Administrator Susan Shaw answered the commissioners’ questions and said the proposed plan for 2017 would make the sixth year in a row to use non-chemical means as a primary way to control noxious weeds. Though non-chemical means is what the conservation district would normally recommend, Shaw said the control is proven effective.
Board Chairman Roger Tellinghuisen, a farmer, said he’d once been doubtful about biological weed control but has now changed his mind after learning more about it. The beetles help boost a growing organic farming economy that must cultivate in an all-natural growing environment, and they cost less to use than the other two methods of control, mowing and spraying.
Lynn Gallice, a conservation technician and assistant agricultural inspector for Mille Lacs County, gathers and distributes the beetles as part of her job. She explained that the conservation districts around the state must all help protect their counties against prohibited noxious weeds the state lists under one of three classifications: eradicate, control and restricted.
“The weeds we’re looking to control are on the state of Minnesota’s noxious weeds (control) list,” she said.
Gallice said different beetles, for example the leafy spurge beetle, are used to control different weed species on the list. In Mille Lacs County, those primarily include leafy spurge, spotted knapweed, purple loosestrife and wild parsnip. Others on the control list are common barberry, narrowleaf bittercress, plumeless and Canada thistle and common tansy.
She coordinates with the state’s agriculture department to procure the beetles. Gallice said when they’re thriving in a particular area, people like her in many counties get a notice to come and get them, usually in the spring. She said if possible, she drops what she’s doing to go and collect the insects using a sweep net, which looks like a butterfly net.
The county is increasing its efforts to place leafy spurge flea beetles, and Gallice said last year was the biggest collection yet at about 11,000 beetles. Other biological controls include the spotted knapweed root weevil, loosestrife beetle and spotted knapweed seedhead weevil.
The beetles get placed into a paper cup-like container with a lid, which Gallice said looks like a to-go soup container. She then gives them a ride to their new home and marks where she puts them using GPS technology. If she cannot make it out to a collection site, the beetles can be shipped overnight with a cold pack, which puts them into a kind of deep sleep until they warm up on the way to their new home.
“They don’t wipe it out, but they control it,” she said about the bugs’ effect on weeds.
For example, the beetles would significantly thin out a thick patch of leafy spurge and effectively keep it from spreading. Shaw and Gallice said biological controls were put into place years ago to control purple loosestrife have been “very effective;” Shaw said it’s not even a weed they’re worried about controlling anymore.
Gallice confirms that noxious weeds can be a problem when they mix into people’s crop fields, especially hay. Wild parsnip has been known to cause health problems; when its juice gets on human skin and then sunlight touches that spot, the skin burns and blisters.
The placement of beetles is a weed control method available to everyone, Gallice said, but they cannot be used in places where private owners or public entities spray for noxious weeds. Gallice said the conservation district is glad to work with landowners and townships on the procurement and placement of biological weed controls.
Another benefit of the beetles are that they’re easy, Gallice said. “All people have to do is leave them alone.”
While some beetle species are not native to the area, Shaw said the methods of research and analysis have improved tremendously over the years so as to prevent any unforeseen and unwanted environmental impacts.
Shaw and Gallice emphasized that natural, sustainable controls are important to people. They want to keep chemicals out of ground and surface water. It remains to be seen how effective beetles will be in the public rights of way, which are typically smaller patches of weeds and a sometimes a difficult environment in which to survive.