Emerald ash borer has been found at Mirror Lake State Park, leading agriculture officials to quarantine Sauk County for the pest.
A number of the adult beetles were caught in one of the purple traps set out around the state to monitor for EAB. In addition, when Wisconsin Department of Natural Resources forest health staff peeled bark from some of the ash trees at the park entrance, they found immature beetles and other signs of infestation. They submitted samples to the Wisconsin Department of Agriculture, Trade and Consumer Protection for initial identification, and U.S. Department of Agriculture officials in Michigan confirmed that they were EAB.
The quarantine will apply to all of Sauk County. It 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 Sauk 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.
Most of the ash trees at Mirror Lake State Park are near the park office. These trees, numbering about 20, will be removed. DNR staff have inspected the few remaining ash trees scattered on the 2,200-acre property. They did not find any evidence of infestation, but will continue to monitor the trees.
Visitors to the park are reminded that they can bring in firewood only if they buy it within 25 miles of the park, or if it is certified pest-free by DATCP. The quarantine prohibits taking any leftover firewood back to their homes.
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 entered 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. In summer, the adults emerge through D-shaped holes in the bark. On their own, they may spread about a half mile per year.
The emerald ash borer first appeared in Wisconsin in 2008 in Washington County. Sauk County will join 16 other Wisconsin counties under quarantine: Brown, Crawford, Fond du Lac, Jefferson, Kenosha, La Crosse, Milwaukee, Ozaukee, Racine, Rock, Sheboygan, Trempealeau, Vernon, Walworth, Washington and Waukesha counties.