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Ash borer found in Superior; Douglas County quarantined

MADISON – Emerald ash borer has been found in the city of Superior, the most northern location in

Wisconsin to date. Douglas County, where Superior is located, will be quarantined.

"While it's disappointing to have found EAB in a new location so far from other infestations, and in

close proximity to our North Woods, it is not surprising, given the ease with which this pest can

hitchhike with the help of humans," said Brian Kuhn, director of the Bureau of Plant Industry in the

Wisconsin Department of Agriculture, Trade and Consumer Protection.

Trempealeau County is the next nearest Wisconsin county where EAB has been found. The other

nearest infestations are in St. Paul, Minn., and in Michigan's Upper Peninsula.

Kuhn said, "Along with the U.S. Department of Agriculture and the Department of Natural Resources,

we set about 1,000 traps in Wisconsin this summer. Almost all of them were set in places where we

have not found EAB previously, and the majority are in the northern half of the state.

The EAB's flight period is just about over for this season, so we'll be taking those traps down in the next couple of

months. When we see what we find in that survey, we'll decide on our next steps."

Members of a Superior city tree crew were removing a dead tree from a boulevard on Aug. 8 when they

found telltale D-shaped exit holes and S-shaped tunnels under the bark -- signs of emerald ash borer


The next day, city employees collected photos and samples of the insects, which were sent

to the Wisconsin Department of Agriculture, Trade and Consumer Protection for initial identification

and to the U.S. Department of Agriculture for confirmation. That confirmation arrived Tuesday, Aug.


The quarantine will apply to all of Douglas County. It prohibits ash wood products and hardwood

firewood from being moved out of the county to areas that are not infested.

For private citizens, this means that they cannot take firewood from Douglas County to non-quarantine

counties. For businesses handling wood products that could carry EAB, it means that they must work

with DATCP to assure that their products are pest-free before shipping.

The quarantine will be put in place temporarily by a Wisconsin emergency rule, until the U.S.

Department of Agriculture completes the process to put a federal quarantine in place.

DATCP recommends that property owners who have ash trees in quarantine counties:

 Keep a close watch on ash trees for signs of possible EAB infestation: Thinning in the canopy,

D-shaped holes in the bark, new branches sprouting low on the trunk, cracked bark, and

woodpeckers pulling at the bark to get to insect larvae beneath it.

 Consider preventive treatments if your property is within 15 miles of a known infestation.

Whether to treat depends on the age, size and number of ash trees. Treatment costs vary

depending on size of the tree and whether you do the treatments yourself or hire a professional.

 Consider planting different species of trees that are not susceptible to EAB.

 Call a professional arborist for expert advice, and visit for detailed


Emerald ash borer is native to China and probably entered the United States on packing material,

showing up first in Michigan about 10 years ago.

It was first found in Wisconsin in 2008 in Washington County

Douglas County will join 19 others under quarantine in Wisconsin: Brown,

Crawford, Dodge, Fond du Lac, Jefferson, Kenosha, La Crosse, Milwaukee, Ozaukee, Racine, Rock,

Sauk, Sheboygan, Trempealeau, Vernon, Walworth, Washington, Waukesha and Winnebago counties.

EAB adults lay eggs on the bark of ash trees in mid- to late summer. When the eggs hatch a week or

two later, the larvae burrow under the bark for the winter and eat the wood, forming the characteristic

S-shaped tunnels and destroying the tree's ability to take up nutrients and water. In summer, the adults

emerge through D-shaped holes in the bark.

The Wisconsin Emerald Ash Borer Program includes partners from the following agencies: Wisconsin

Department of Agriculture, Trade and Consumer Protection; Wisconsin Department of Natural

Resources; University of Wisconsin – Madison; UW-Extension; United States Department of

Agriculture- Forest Service and Animal and Plant Health Inspection Service.

Steve Dzubay

Steve Dzubay has been publisher at the River Falls Journal and Hudson Star Observer from 1995-2016. He holds a bachelors degree in journalism from the University of Minnesota. He previously worked as a reporter-photographer at small daily newspapers in Minnesota and is past editor of the Pierce County Herald and River Falls Journal.