The Emerald Ash Borer Dilemma comes to Woodford County - U of I Extension

News Release

The Emerald Ash Borer Dilemma comes to Woodford County


July 17, 2018

The infamous pest amongst the trees through Woodford County


EUREKA, Ill. – This infamous pest, among other means, has spread by transporting firewood across Illinois, killing millions of Ash trees in the last few years. “With the presence of Emerald Ash Borer (EAB) in Woodford County, homeowners and city officials must consider lengthy and costly treatment or loss and replacement of valuable urban trees,” states University of Illinois Extension Horticulture Educator, Kelly Allsup.


The town of Normal, where Emerald ash borer was also detected in 2008, opted for removal and replacement. The Town of Normal Parks Supervisor, Tom Cherry said, “The Town of Normal has taken down over 500 ash trees including 150-year-old trees. The ash is fast growing and was a favorite landscape tree of the time making up about 20% of the city tree population.” He says that there has been “100% detection of Emerald ash borer when symptoms show. The removal of the ash trees has given the town of Normal the opportunity to plant more diverse groups of trees while working with Ameren to plant trees that will not grow into power lines. Cherry mentioned that The Town of Normal Emerald Ash Borer Removal and Replant Plan has been successful thus far.


It is not a rare sight to see an ash tree on the parkway in Bloomington/Normal afflicted in some way by the infamous Emerald ash borer. Symptoms start with branch tip die back and thinning of the canopy, then over time, the entire tree dies, to leave behind naked bare eyesores and safety hazards. Another telltale sign is the sprouting, growth of new branches and leaves clustered along the trunk or the roots of the tree. When original branches are killed by the larvae (worm-like) of the beetles that live and dine on the inside of the tree blocking major food and water transportation, the tree tries to compensate by sending out this new growth, called epicormic shoots.

 How to manage EAB and its impact on trees remains difficult, and the dilemma does not come from if your prized ash has the problem, but rather how you intend to address the problem. Once Emerald ash borer is detected in a community, it takes only a few years before a devastating population boom of EAB occurs and visible signs of its presence become obvious and widespread. For homeowners in Woodford County, the population is rising and some have opted for treatment to save the brilliant fall displays of their ash trees.


Just a few guidelines for EAB treatment includes (if more than 50% of your tree canopy remains):

o    Treat with yearly applications of a systemic chemical drench with the active imidacloprid for trees

o    Hire an arborist to make a trunk injection of pesticides containing imidacloprid, dinotefuran, or ematmectin benzoate during the months of May and June. Emamectin benzoate will last up to two years and may provide protection for three years.

o    Cut the tree down, remove the stump and plant a replacement. The larvae live in the outer layer of the tree and must be destroyed and not moved outside the county. Allsup says, “This option may be the most environmentally sound if we are to reduce the impact of the Emerald ash borer, prevent years of chemical use, and it allows opportunities to plant a more diverse population of trees in the county. However, everyone needs to be aware of the results of tree loss which include, but are not limited to; increased heating and cooling expenses, increase water use, decreased water absorption which leads to erosion and flooding, decreases in property value, and sentimental losses.” A common rule of thumb for most Horticulturists is to always plant different species of trees than what your neighbors have.

o    If nothing is done. If you are not treating or removing the tree, then the population will continue its spread across the county. Removal of trees can be costly and cumbersome for many.


Emerald ash borer is proving to be a major dilemma because making the most environmentally sound choice will come at high costs to homeowners and cities. It should also be noted that ash trees have numerous wildlife species depending on them at least sometime in their lifecycle and this will prove a great loss. For more information on the Emerald Ash borer, please visit


For more information on this topic, please contact us at the next Woodford County Master Gardener Information Booth at Eureka Library from 4:30 to 6 p.m.

on Monday, August 6.



Source: Kelly Allsup, Extension Educator, Horticulture,

Pull date: July 17, 2019