EAB In FDL And Dodge Counties

Emerald ash borer has been found at Mauthe Lake in Fond du Lac County, and in Watertown’s Riverside Park in Dodge County.

As a result, Dodge County will be quarantined. Part of Watertown also lies in Jefferson County, which is already under quarantine for EAB because of its proximity to infestations in neighboring counties.

Fond du Lac County has been under quarantine for emerald ash borer since 2008, because of its proximity to infestations in neighboring Washington County. However, this is the first time the tree-killing insect pest has been found in Fond du Lac County.

Wisconsin Department of Natural Resources staff found an adult beetle in a trap set at the Mauthe Lake campground in the Northern Unit of Kettle Moraine State Forest.  They submitted the beetle to the Wisconsin Department of Agriculture, Trade and Consumer Protection for initial identification, and U.S. Department of Agriculture officials in Michigan confirmed that it was EAB.

DNR staff will remove a number of unhealthy-looking ash trees in the immediate area, and will examine them for signs of EAB.  The pest poses a minimal threat on most of the 30,000-acre Northern Unit, because it contains few ash trees. Ash trees make up more than a quarter of the trees on 3,000 acres, and EAB will likely have greater impact there. 

The Dodge County find was also caught in a monitoring trap that had been set along the Rock River in Riverside Park just north of the Dodge-Jefferson county line. There was no obvious damage to trees nearby.

For Fond du Lac County, the find does not change anything from a regulatory standpoint, since the county is already under quarantine. The Dodge County quarantine will be put in place by Wisconsin emergency rule until a federal quarantine can be enacted.

The quarantine prohibits wood products from being moved out of the county to areas that are not infested. For private citizens, this means that they cannot take firewood from Fond du Lac County or Dodge 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.

Visitors to the state forest are reminded that they can bring in firewood only if they buy it within 25 miles of the campground, or if it carries the DATCP-certified label.

Property owners in quarantined counties should take these measures:

  • 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 for property within 15 miles of a known infestation. Whether to treat depends on several factors: the age of the trees, the size of the trees, and the number of 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.
  • Contact a professional arborist for expert advice, and visit emeraldashborer.wi.gov for detailed information.

Emerald ash borer is native to China and was first found in the United States about 10 years ago on packing material, showing up first in Michigan. EAB adults lay eggs on the bark of ash trees in mid- to late summer. When the eggs hatch a few weeks later, the larvae burrow under the bark for the winter and eat the wood, destroying the tree’s ability to take up nutrients and water and killing it within a few years. In summer, the adults emerge through D-shaped holes in the bark. On their own, they may spread about a half mile per year.

It appeared in Wisconsin in 2008 in Washington County. Dodge County joins 17 other Wisconsin counties under quarantine:  Brown, Crawford, Fond du Lac, Jefferson, Kenosha, La Crosse, Milwaukee, Ozaukee, Racine, Rock, Sauk, Sheboygan, Trempealeau, Vernon, Walworth, Washington and Waukesha counties.