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
"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 emeraldashborer.wi.gov 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.