knapweed

(Photo by Flickr user JanetandPhil)

Researchers from Michigan State University are trying to control an invasive plant called spotted knapweed. They’ve released two foreign beetles that eat the plant on small plots of state land.

Knapweed spreads a carpet of purple flowers over old farm fields and alongside roads in mid-summer.

But as The Environment Report's Bob Allen discovered, beekeepers rely on those flowers for making honey.

Spotted knapweed tends to dominate any landscape where it takes hold. Its roots send out a chemical substance that kills nearby plants.

But researchers in several states think they’ve found a way to keep it in check. They’ve released two species of tiny European weevils.

One attacks knapweed’s roots, the other eats its seeds.

Doug Landis is a bug specialist at Michigan State University. He says in some test plots the bugs have knocked knapweed back as much as 80%.

“These insects don’t eliminate knapweed. But they can reduce its density to the point where it becomes a more manageable part of the plant community.”

Knapweed is found in every county in Michigan but especially in sandy soils. And land managers want to get rid of it because it crowds out native wildflowers and grasses that supply food and shelter to a wide variety of insects, birds and other wildlife.

But beekeepers say the plant has a lot of value for them. They even have a more poetic name for it... star thistle. And they say it produces a light, mild, pleasant tasting honey that puts northern Michigan on the map.

“It’s one of the best honeys in the country.”

Kirk Jones runs Sleeping Bear Apiary in Benzie County.

He says his star thistle honey is in demand in stores and restaurants across the country.
And it’s the only source of surplus nectar available for his bees late in the season.