Emerald ash borer (EAB) is a very serious problem that threatens all ash trees in the Midwest. EAB was first discovered in Wisconsin in 2008 and is now found extensively in southeast Wisconsin and northern Illinois. There are currently 39 Quarantined Counties in Wisconsin (see map - updated August 18, 2015). EAB has now been found in over 30 Wisconsin counties including the southwest counties of Kenosha, Racine, Walworth, Milwaukee, Ozaukee, Washington, Waukesha, Dodge, Jefferson, and Dane. For more information on where and when EAB has been discovered in Wisconsin please see this list of confirmed finds of EAB in Wisconsin.
A commonly asked question is, “What can I do to keep my ash tree?”. The answer to this question may vary somewhat depending on your individual circumstance. Much has been learned about this insect over the last several years, and new research continues to help us make better decisions regarding treatments to save ash trees. One thing is certain; treatment is required to keep your ash tree protected.
Points to consider:
- Serious consideration should be given to healthy, high value, important trees for treatment: i.e. specimen trees, ones shading key areas, sentimental etc.
- Trees should be healthy. Ash trees have many other potential health problems other than EAB. This helps to ensure the treatments will be as effective as possible.
- Research has shown trunk injections with Emamectin Benzoate performed every other year have been up to 99% effective, even in locations with high EAB populations.
- Another strategy is to remove small and/or poor quality ash trees and plant new trees.
When should treatment be started? Studies have shown protection prior to EAB discovery is most effective. Keep in mind everywhere EAB has been found, it had been present for 3 to 6 years before discovery! In summary, the earlier treatments begin the better chance you have of saving your tree from damage.