Emerald Ash Borer (EAB) is an invasive and destructive insect pest of Ash trees (Fraxinus sp.) that was discovered in Michigan in 2002 and first found in Illinois in July of 2006. Since that time EAB has been spreading throughout Illinois and 29 other states in the US.
In 2017 EAB was positively confirmed in Quincy, IL and Nauvoo, IL
The destructive life stage of EAB is the larva. After females lay eggs on the bark of ash trees and the eggs hatch, the larva burrow their way into the tree where they feed on the conductive tissues of the tree. As EAB populations build up, enough damage is done that the tree is starved as all the pathways that allow for movement of nutrients and water are destroyed. Without treatment, mortality rates in ash are 100%.
Current research recommendations are to begin treatment when EAB has been confirmed within 10-15 miles of a community. There are a few treatment options available with injectable chemicals such as Tree-Age having a high rate of control on EAB (this is a professional treatment option). There are options for homeowners to apply on their own property, though soil drenches have shown inconsistency in control of EAB especially in larger trees – it's recommended that any tree over 20" in diameter be treated by a professional arborist. Tree-Age and TreeAzin, both of which are injectable chemicals, can provide 2 years of control from one treatment. It should be noted that TreeAzin provides 2 years protection in areas with low EAB populations, but as populations grow it needs to be applied every year for control. Treatments can begin in spring after ash trees have bloomed.
You can read additional information about treatment options in the following 2 documents:
http://www.emeraldashborer.info/documents/Multistate_EAB_Insecticide_Fact_Sheet.pdf
http://www.emeraldashborer.info/documents/PM2084%20EmeraldAshBorer%20Revised%20Dec2016_Iowa.pdf
Before deciding to treat for EAB the tree should be evaluated on health, quality, and location. For example if the Ash is located near power lines and will be trimmed to allow for clearance that tree would not be considered a viable candidate for treatment. Other examples that would indicate an ash tree is not a viable candidate for treatment would be severe storm damage, the tree is in decline, or has more than 30% canopy decline from EAB infestation.
If you chose to have trees removed or treated make sure to contact a qualified insured arborist.
University of Illinois Extension Adams, Brown, Hancock, Pike & Schuyler Counties will be offering workshops to provide more in-depth information about EAB, management, and treatment beginning late winter. If you have any questions about EAB you can contact Kari Houle, Extension Educator Horticulture via email at khoule@illinois.edu or via phone at 217-357-2150.