Purple beetle beaters
At first glance, they might appear to be wood duck houses built by someone with an affinity for The Purple.
And that wouldn’t be unusual
in these parts, where Vikings purple shows up in the most unusual of places.
But these aren’t wood duck houses, and the color has nothing to do with Purple Pride. No, this is more serious business. It’s about Minnesota’s treasured woodlands.
The purple “houses” are actually traps, and they’re covered in a sticky substance in an attempt to “catch” emerald ash borers (EAB) as part of a massive survey going on in the Brainerd lakes area and across Minnesota, home to 998 million ash trees, according to the Minnesota Department of Agriculture.
The traps hang in the treetops of ash trees and, for the most part, aren’t readily visible, even though they’re purple — the beetles are believed to be attracted to purplish hues. Instead, most people will see a poster on the lower portion of the tree, indicating that it is part of the survey.
The traps can be found across the lakes area. One trap, hanging high from an ash tree at the boat access on the north end of Lake Sibley in Pequot Lakes, was caked with insects, but no EAB. Such negative results have been the norm across Minnesota.
And while EAB have only been found in four counties in the southern part of the state — Hennepin, Ramsey, Ford and Winona — the DNR and Minnesota Department of Agriculture aren’t taking any chances. If EAB reaches Brainerd and timber-heavy northern Minnesota, the results could be devastating. EAB, an invasive beetle from Asia, feeds on and kills ash trees within a few years of infestation.
In the Brainerd area, thick with ash trees and where campfires are a staple of summer, the main concern is firewood.
“It’s directly related to the transportation of firewood by people,” said Mike Locke, region silviculturist — or forester — for the DNR. “They (EAB) don’t fly very far on their own. They’re mostly (transported) by people moving wood. It’s why we have all the rules on firewood. In Brainerd there’s much more of a risk. It’s closer to some ash sources. And Aitkin and Crow Wing counties have more ash.”
According to Liz Erickson, communication coordinator for the MDA, nearly 6,000 of the traps have been positioned “fairly evenly across the state.” Erickson said 15 “trappers” will check the traps later this summer.
She said the outer walls of the triangular, 2-foot-tall traps are smeared with a sticky compound called tanglefoot and inside, hexanol and manuka oils give off the scent of distressed ash trees. That’s a sure-fire way to lure the beetles, but so for, no EAB in the traps outside of those four southern Minnesota counties and nothing since last year, when there was a new infestation in Winona County, Erickson said. And while the focus is on northern Minnesota, the MDA is keeping an eye on the state as a whole, continuing to study other ways to combat EAB.
“Northern Minnesota is where the majority of ash trees are so we’re concerned about (EAB) being in that area,” Erickson said. “We’re working with a forest study with cold, hardy studies to see if the temperatures get down to a certain point, if it kills them. But we’re still studying that. We’re hoping the cold will work in our favor. And we’re concerned for western Minnesota. And the University of Minnesota has done surveys and 80 percent of the trees in the Twin Cities are ash.”
“The potential is there,” Locke said of EAB around Brainerd and to the north. “There’s an effort with Chippewa National Forest, the DNR, the Leech Lake tribe and surrounding counties to come up with a management scheme in that localized area. Eventually they (EAB) will get up there and start taking out the ash.”
And that would be a travesty for the area as a whole.
“Ash trees are usually found in a wet environment. If all the trees in a stand die, it upsets the hydrology,” Locke said. “If they get killed all at once it will get a lot wetter. It could flood out the site. And it makes it tough for other trees to come back in.”