Ash borers confirmed in Minnesota

A tree killing insect that experts fear could wipe out millions of ash trees in the Northland was confirmed for the fist time in Minnesota on Thursday.

A tree killing insect that experts fear could wipe out millions of ash trees in the Northland was confirmed for the fist time in Minnesota on Thursday.

The Minnesota Department of Agriculture said emerald ash borer was found in St. Paul near the intersection of Highway 280 and Interstate 94.

The state will place Hennepin and Ramsey County under quarantine, meaning no firewood or ash nursery stock or ash timber can be moved out of those counties.

A tree service suspected the insect Wednesday and called in the state which sent samples and photos to U.S. Department of Agriculture insect experts.

"We sent digital photos of the larvae to the USDA and they confirmed it immediately,'' said Michael Schommer, spokesman for the Minnesota Department of Agriculture.


Already on Thursday, state officials were finding more and more of the infested trees in St. Paul. It's not clear how the bugs got there or how large the infested area is.

"I'm standing a couple of blocks for the original finding and we're seeing more trees that appear to be infested. So it's probably at least many trees over a several-block area,'' Schommer said. "We were hoping it wouldn't jump this far into Minnesota this fast.''

While the finding wasn't unexpected it marks a major hurdle north for the insect that's expected to take a devastating toll on both urban and forest ash trees across the state.

Unlike other forest pests that only stress and kill some trees, emerald ash borer has been 100 percent fatal to all trees it hits and all varieties of ash.

Experts say little can be done to stop the insect, but they say action by residents - namely not moving firewood - can help slow the spread as experts work to find some sort of weapon to stop the bug.

The Twin Cities finding comes just a few weeks after the insect was found in western Wisconsin.

Minnesota and Wisconsin officials have asked all residents and tourists not to move any firewood more than a few miles from where it was cut -- and especially not to bring it north when they vacation.

Northern Minnesota and Wisconsin are considered vulnerable to emerald ash borer because of the millions of ash trees that grow in the wild and the large number of urban ash trees. There are 765 million ash trees in Wisconsin forests and 820 million in Minnesota. Experts say all are at risk because the bugs have no natural enemies here.


Emerald ash borers first were discovered in the Detroit area in the 1990s after arriving in the U.S. in shipping crates from China. In less than a decade, the bugs have spread and killed millions of ash trees in Michigan, Indiana, Ohio, Pennsylvania, Maryland, Illinois, West Virginia, Virginia, Missouri, the Canadian Provinces of Quebec and Ontario and now Wisconsin and Minnesota.

The adult emerald ash borer is a metallic green insect about one-half inch long and one-eighth inch wide. The adult female deposits eggs on the bark of ash trees. The larvae hatching from the eggs chew their way through the bark, and into the soft layer of wood just beneath. There, they eat their way through the tree's vascular system, cutting off the flow of water and nutrients in the tree, leading to decline and eventual death of the tree.

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John Myers reports on the outdoors, natural resources and the environment for the Duluth News Tribune. You can reach him at
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