Minnesota fights advancing gypsy moth
by Dan Gunderson, Minnesota Public RadioThe Minnesota Department of Agriculture is spraying for gypsy moths along the North Shore this week. The insects can cause serious damage to forests, and they're slowly moving into Minnesota from Michigan and Wisconsin. While the front line in the fight against the gypsy moth is along the the state's eastern border, campers and hunters are bringing the pests to other parts of the state.
Elm Lake WMA, Minn. — The gypsy moth arrived in North America in the 1860s, brought by a Frenchman hoping to create a new silk industry.
The moths escaped and with few natural predators to control the population, they've been spreading ever since.
The gypsy moth expands its territory less than 15 miles a year, except when it gets help from people.
That's why John Haanstad, who works for the USDA, is at a remote campsite on the Elm Lake Wildlife Management Area near Thief River Falls. This spot is used mostly by hunters in the fall.
Haanstad checks his laptop computer, where a map shows purple dots representing about 20 gypsy moth traps.
Haanstad is helping other federal and state agencies find and control insect infestations.
He'll check gypsy moth traps in this isolated area some 200 miles from the state's eastern border because last fall, the U.S. Fish and Wildlife Service found gypsy moths here.
"We caught two gypsy moths here so there's an introduction here," explains Haanstad. "But does it take? Is there a critical mass of gypsy moths to get established here?"
How did gypsy moths jump 200 miles ahead of the slowly advancing front line on the state's eastern border?
They most likely hitchhiked on a hunter's camping gear.
There are large populations of gypsy moths in Wisconsin, Michigan and many other states in the northeastern U.S.
The USDA's John Haanstad, says hunters and campers should check their gear after traveling to Minnesota's north shore, Wisconsin or Michigan. He says the gypsy moth often lays it's eggs on firewood or camping gear.
"The gypsy moth egg mass is about the size of a silver dollar," Haanstad says. "They're very easy to see, the color is very distinctive. It's furry, salmon-colored, about the size of a silver dollar. You can't miss it."
On this damp July morning, John Haanstad is checking small cardboard traps that use a female moth pheromone to lure male gypsy moths into the trap.
DNR area Wildlife Manager Doug Franke tags along to learn about the gypsy moth, a new threat in his part of the state.
"DNR in this part of the state is pretty ignorant about gypsy moths, and we want to keep it that way," says Franke.
He worries about the gypsy moth impact on the oak savannahs that dot northwestern Minnesota
Franke says the DNR is stepping up efforts to educate hunters and campers.
"Our goal and hope is that people start getting it," he says. "Start understanding what they do every day and what action causes another action."
In the middle of a small aspen grove, one of the gypsy moth traps is stapled to tree. John Haanstad peers inside.
"There's a moth in this trap but it's not a gypsy moth because I can see it's antenna," he says. "You want to come around and see it, Doug?"
Hanstaad points out to Doug Franke the insect's long thread-like antenna. A gypsy moth's is feathery and he describes how you can see feathers on the antenna. Haanstad will be check these traps two more times this summer and this spot will be monitored again next year.
If more gypsy moths are found, the area will be sprayed to eradicate the insects.
Haanstad says if the gypsy moths are found quickly, they can almost always be successfully controlled.
"There are introductions we probably don't even see." he says. "That's how gypsy moths are spread in the environment. We're lucky to see this one. Maybe we can get a handle on a population that might be starting here. "
This remote northwestern campground is one of the deepest incursions the gypsy moth has made in to Minnesota.
But new hot spots pop up each year. Just last week a gypsy moth caterpillar was found in Itasca State Park, riding in with campers from Madison, Wisconsin.
The Minnesota Department of Agriculture does most of the gypsy moth monitoring in Minnesota, scattering about 20,000 traps around the state every year.
MDA Gypsy Moth Trapping Coordinator Kimberly Thielen Cremers says much of the gypsy moth expansion in Minnesota is because of human activity. She says stopping those small populations saves trees and money.
"For every dollar we spend on this early detection program, we are saving the state $22, was the gypsy moth to become established and all the damage that's done once it's here. We need to control the population," says Thielen Cremers.
Minnesota officials say with no statewide gypsy moth infestation yet, the best protection is good surveillance.
