More than one million tiny weed-eating beetles have been released in endangered wetlands around the state by the Department of Agriculture. Since the early '90s, beetles have been used as nature's foil to purple loosestrife, a noxious, invasive weed that has crowded native plants out of more than 50,000 acres in Minnesota. Now a group of Red Wing High School students plans to build on the beetles' success, by introducing them to a new loosestrife-ridden site. But first, they have to catch some.
Purple loosestrife is a beautiful, but noxious, plant that invades marshes and lakeshores, harming ecosystems and reducing the diversity of wetland plants. (Photo courtesy of Minnesota DNR)
CARLOADS OF FISH AND WILDLIFE STUDENTS BUNCH OUT
along the edge of a waterway in Frontenac State Park, not far from their Red Wing school. Armed with small plastic bottles, students in waders and tennis shoes examine tall purple-flowered reeds for galerucella beetles.
"There are a lot of them," says student Trent Nolton. "You can see where the beetles have eaten away, so you look for the leaves that are eaten away and then you look for the top at the buds."
As beetles feast on loosestrife leaves and budding flowers, in the process they kill the plant. This method of bio-control has proven more effective than chemicals or pesticides. Those can kill indiscriminately, claiming native and non-native plants alike.
Science teacher Steve Nelson designed the project. It calls for each student to collect roughly 60 beetles, which will spend their summer deposited in mesh-covered plastic swimming pools. The beetles will be treated to as much loosestrife as they can eat. Students will determine the most effective ratio of beetles per plant before taking the bugs out to a new loosestrife population, to continue their study outdoors.
Nelson surveys dry branches, gray and brittle - this is loosestrife in its final stages. Without help from the galerucella beetles, Nelson says this plant would be green and flowering, producing more weeds from its own 2.5 million tiny seeds.
"This would eventually keep building in until this pond was filled in with this mass. We hope to see the end result of the kids' work in the future, by having this pond cleared again, as well as the ones across the road," Nelson says.
Another student, sophomore Kyle Neehoose, carefully drops the bugs into his container. Although he is an avid hunter and fan of the outdoors, Neehoose was unaware of purple loosestrife.
Students from Red Wing High School's fish and wildlife class collect beetles which eat and kill purple loosestrife. (MPR Photo/Erin Galbally)
"I couldn't even have picked it out if they told me one in five plants are purple loosestrife - I would have no idea what it looked like. Then we went out and found some," Neehouse says.
Farther down, a group of three boys rummage around the water's edge - finding that some bugs are easier to deal with than others.
"I come out here to help the environment. It doesn't take a whole lot of time so it's not so bad, I just don't like all of the wood ticks."
Before the students head out the wetland, Department of Agriculture agronomist Kevin Ballman reminds them to keep a lid on the precious cargo.
"You don't want any of those beetles coming out. You don't want them all over your car," Ballman says. "Believe me, they start crawling on your shoulders and they really like you - at least they did me."
So the lids are fastened, and the beetles - still munching on loosestrife leaves - are carted off to their new destination.