Download LISMA September 2014 article, Emerald Ash borer

A lot of effort has been put into education on invasive species. Most of the focus has been on aquatic
invasive species, particularly those spread by boats. This includes things like zebra mussels (Dreissena
polymorph), Eurasian watermilfoil (Myriophyllum spicatum), and spiny waterfleas
(Bythotrephes longimanus). The Wisconsin Department of Natural Resources and UW Extension have
been training volunteers to educate boaters at public boat landings on ways to prevent the spread of
aquatic invasive species from one lake to another. There has also been focus on terrestrial plants such
as common reed (Phragmites australis), giant hogweed (Heracleum mantegazzianum), and garlic
mustard (Alliaria petiolata). Local groups, such as the Lakeshore Invasive Species Management Area
(LISMA), have been educating landowners and organizing work parties to control terrestrial invasive
plants. However, there are other invasive species that maybe haven’t received the attention they
deserve. One of these species is the emerald ash borer (Agrilus planipennis).
The emerald ash borer was first found in the United States in 2002. It originated in Asia, and is thought
to have arrived in the wood of shipping crates. Once in the United States, it has been largely
transported by people. The emerald ash borer will only fly a few miles on its own. Once emerald ash
borers have found an ash tree, the tree will die in 2 to 4 years. Emerald ash borer 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 feed. The larva feed on the inner bark of the tree compromising its
ability to transport food and water, leading to starvation. The adults emerge through D-shaped holes in
the bark. Signs of an emerald ash borer infestation include thinning canopy, D-shaped holes in the bark,
cracked bark, and branches sprouting low on the trunk. In forests with a large population of ash trees,
the death of these trees creates an opening for invasive shrubs and trees to come in to the forest.
In Wisconsin, emerald ash borer was first discovered in Ozaukee County in 2008. The most recent
discoveries occurred in Adams County and Sheboygan County in August 2014. Currently 32 Wisconsin
counties are quarantined. These counties are Adams, Brown, Buffalo, Columbia, Crawford, Dane,
Dodge, Door, Douglas, Fond du Lac, Grant, Green, Iowa, Jefferson, Juneau, Kenosha, La Crosse,
Lafayette, Milwaukee, Monroe, Ozaukee, Racine, Richland, Rock, Sauk, Sheboygan, Trempealeau,
Vernon, Walworth, Washington, Waukesha, and Winnebago.
The Lakeshore Invasive Species Management Area (LISMA) is a broad-based coalition that promotes
effective management of invasive plant and animal species throughout the 4-county region of Fond du
Lac, Calumet, Manitowoc, and Kewaunee Counties, Wisconsin. With one of the counties in our area
already quarantined and the other counties surrounded by quarantined counties, it is important to be
aware of the emerald ash borer and the potential impact it can have on the forests. Being proactive in
ensuring a diverse native forest (not dominated by ash tree species) may be the most cost effective way
to prevent secondary invasions of non-native trees and shrubs in the aftermath of emerald ash borer
infestations. Once invaded, lots of resources (time and money) are needed to convert the forest back to
a native species dominated ecosystem. As the old saying goes, an ounce of prevention is worth a pound
of cure.
For more information, contact Jennifer Powell at (920) 793-4007 or [email protected].