Emerald Ash Borer
If you are a tree service provider and wish to chemically protect a public street tree against emerald ash borer, city ordinance requires you to first complete a Tree Work Permit Application.
Emerald Ash Borer is an invasive wood boring beetle that feeds on the tissues under the bark of ash trees and kills them. It is native to East Asia and was accidentally imported to the United States within the wood of shipping crates from China. EAB was first discovered in North America near Detroit, Michigan in 2002. Since then the beetle has spread to several eastern and Midwestern states, including Wisconsin. EAB has also been found in Canada.
EAB is not a threat to human health but it does threaten our forest and urban tree populations. EAB is 100 percent fatal to our native ash trees of any size, any age, healthy or unhealthy, (according to research by Michigan State University and the US Forest Service).
The larva (the immature stage of EAB) spends its life inside ash trees, feeding on the inner bark where we cannot see it. This feeding disrupts the trees' ability to transport water and nutrients, causing the tree to starve and eventually die. On its own, the beetle will only fly a few miles. However, it is easily and quickly transported to new areas when people inadvertently move emerald ash borer larvae inside of infested firewood, ash nursery stock, and other ash items.
A tree that has been attacked by EAB can die within 2-4 years. It is estimated that more than 50 million ash trees are dead or dying in the Midwest because of this insect. Wisconsin forests contain more than 770 million ash trees, nearly 7 percent of the tree population. In urban areas, we estimate that ash make up, on average, 20 percent of trees.
Where Has EAB Been Found?
Emerald ash borer was found for the first time in Wisconsin in August, 2008 near the community of Newburg, along the northern Ozaukee and Washington County line. In April, 2009, EAB was found in western Wisconsin, in the small town of Victory in Vernon County, alongside the Mississippi River. In July, adult beetles were caught on survey traps located in Crawford and Brown counties. In August, the Milwaukee County community of Franklin confirmed the presence of EAB when city officials alerted program staff to declining ash trees. The presence of emerald ash borer beetles was confirmed in Racine County in July 2011. The beetles were found in traps at three locations; infested trees have not yet been found.
Why Should We Care About EAB?
The potential devastation wrought by emerald ash borer upon Wisconsin's urban and community forests could exceed that of any other forest pest in the recent past. Ash trees are common in both rural and urban areas throughout the state, but EAB will strike cities and villages especially hard. Though ash makes up about 7% of trees in the state's rural forests, it makes up about 20% of the trees in our urban forests. In some Wisconsin communities the proportion of ash is much higher. Ash, especially green ash, is very common in urban areas because it was a popular replacement for the American elm.
Of the state's 770 million ash trees, approximately 5.2 million exist on public and private property within cities and villages. The loss of these urban ash trees would cost property owners and taxpayers:
... $1.5 billion for tree replacement
... $776 million for tree removal and disposal
... $13 million per year in lost tree-canopy function to reduce pollution, lower heating and cooling costs, & absorb storm water runoff
EAB is not a "business as usual" tree pest. It kills quickly and thoroughly. It has completely overwhelmed the staff & budget resources of most communities in infested areas.
What Can Homeowners And Businesses Do?
- Don't plant ash trees; plant a variety of other species.
- Consider chemically treating high value ash trees.
- Don't move firewood out of Racine County; moving firewood out of the County has been prohibited by law. If you have an EAB infested tree that you would like to use as firewood, note that EAB larvae in a downed tree can survive and emerge from the firewood pile for up to two years; wait until late autumn to take down an infested tree and be sure to use up all of the wood from that tree by spring.
An EAB Guide For Homeowners
Homeowners Guide to Emerald Ash Borer Insecticide Treatments
Insecticide Options For Protecting Ash
For additional information visit Wisconsin's Emerald Ash Borer Information Source.