A metallic green insect smaller than a penny threatens to destroy Minnesota’s 867 million ash trees.
Local agencies are concerned after the emerald ash borer was found recently in Wisconsin and Missouri and have taken steps to delay its introduction to the state’s ash trees.
The insect, native to Asia, was found in Detroit in 2002 and has since spread to nine states and two Canadian provinces via the movement of ash firewood and other ash materials.
Since its introduction to ash trees in the United States in 2002, the insect has destroyed more than 25 million ash trees, according to the U.S. Department of Agriculture.

Voyageurs National Park
Northern Minnesota has a large population of ash trees and the introduction of the emerald ash borer to ash trees in Voyageurs National Park has the “potential to be devastating,” according to John Snyder, biologist at VNP.
If the ash is destroyed, it could lead to a “significant change in the ecosystem” in VNP, according to VNP Chief Ranger Jim Hummel. As the ash trees would die, other species would take over, Hummel said, noting that what species would fill in is unknown.
If the emerald ash borer is found in VNP, there is no practical way to eliminate the insect, Hummel said. Instead, the park would attempt to minimize the effects of the emerald ash borer and attempt to contain its spread, he said.
From a management standpoint, it’s a “head scratcher,” Hummel said. A large amount of research has been done on the insect as a result of it being an exotic species, but little research has been completed on how to eradicate it.
Park staff have begun checking for the insect in the park, according to Snyder. As a part of an effort to detect the insect within the park, staff have set up emerald ash borer traps. Visitors may see the sticky purple triangle traps hanging from trees, Snyder said. The insects are attracted to the color purple.
The traps are expected to be collected at the end of the summer. VNP staff plan to send anything on the traps that resembles the insect to a national lab for identification, Snyder said.
The park has also instituted the same firewood restrictions used by the Minnesota Department of Natural Resources. On its own, the emerald ash borer could take two to three years to migrate to Minnesota. But it can travel to Borderland in one day on firewood brought into the state, Snyder said.
It became illegal last year to bring firewood onto state-administered lands unless it’s DNR approved, according to the DNR. Only firewood from DNR-approved vendors can be brought into VNP also, according to Snyder.
Park staff are also attempting to educate visitors about the emerald ash borer by discussing the potential impact the insect could have, Snyder said. VNP had voluntary restrictions on firewood last year because it was more about educating the public, according to Hummel.
The restrictions have been made mandatory this year, he said. Instead of bringing firewood into the park, visitors can use trees around a campsite, Hummel suggested, adding that the trees used should be down or dead. Park staff have noticed that live trees are being cut around campsites, he said.
But the education is more about changing people’s habits to delay the introduction of the emerald ash borer to the state, Snyder said. By aligning with state and federal agencies on prevention measures, it’s sending a unified message to the public, he said.

County and state
The emerald ash borer was confirmed in Ozaukee County in southern Wisconsin Aug. 1 by officials with the Department of Agriculture, Trade and Consumer Protection and the Wisconsin DNR. The discovery was made by forest health specialists investigating a citizen report of dying ash trees in a private wood lot, according to the DATCP.
Ozaukee County is expected to be quarantined, which means a ban has been placed on the movement of hardwood firewood, ash nursery stock, timber and any other article that could spread the emerald ash borer. A thorough study of the area is also expected to be completed to determine the infestation size, its boundaries and the possible source, according tot he DATCP. Neighboring counties may also be quarantined.
The insect was also found in July in southeastern Missouri and officials believe it was transported into the state on firewood, according to the Missouri Department of Conservation.
Koochiching County’s Land and Forestry Department staff will react once they know more about the incident, Land Commissioner Dennis Hummitzsch said. As of now, it is an isolated find, Hummitzsch said. When little is known about the discovery in Wisconsin, it’s difficult to form a strategic plan for the county.
Ash is a large portion of Koochiching County’s forests, according to Hummitzsch. The trees can be found in stand-alone stands of trees and as understory, he said.
There is little Koochiching County staff can do to prevent the introduction of the insect to the county’s forests, Hummitzsch said. But the county has taken steps to detect the insect in the county. Land and Forestry staff have worked with the U.S. Department of Agriculture to set up the emerald ash borer traps in county parks, he said, adding that a potential exists for infected firewood to come into the parks.
Hummitzsch also cautioned residents that there are several green insects in Koochiching County that are similar to the emerald ash borer and several insects, such as the pine weevil, that create galleries in trees similar to the emerald ash borer.
The findings have no immediate effect on Minnesota, according to Val Cervenka, forest health program coordinator with the Minnesota DNR.
In Wisconsin, officials felt that the emerald ash borer was already established in the state but hadn’t yet been found, Cervenka said. The Minnesota DNR also believes that about Minnesota, she said.
Minnesota DNR staff are not changing measures the agency is taking to prevent the spread of the insect, Cervenka said. But agency staff are continuing to discuss the potential impact the emerald ash borer could have on the state’s forests.

Detecting emerald ash borer
Adult emerald ash borers are bright metallic green. They are 1/2-inch long with a flattened back and purple abdominal segments beneath their wing covers.
The creamy white larva are legless with flattened bell-shaped body segments.
Signs of an emerald ash borer infested tree are canopy die back that begins in the top one-third of the canopy and continues until the tree is bare. Sprouts also grow from the roots and trunk with leaves that are larger than normal. The bark splits vertically as a result of callous tissue formation with the insect’s galleries exposed under the bark split. The larval feeding galleries weave back and forth across the woodgrain. Adults form a D-shaped hole upon emergence. Woodpeckers feed on the emerald ash borer larvae and as a result, woodpecker activity and damage is increased on the infected tree.
If you suspect a tree is infected with the emerald ash borer, contact the Minnesota Department of Agriculture’s “Arrest the Pest” hotline at 1-888-545-6684.
-Information from Michigan State University Extension

DNR approved firewood vendors
International Falls: Demars Wood Processing, Kroll’s Firewood, Northland Distributing
Kabetogama: Arrowhead Lodge, Gateway Store, Jim’s Ash River Trail, Pine Ridge