The Emerald Ash Borer Problem

by Matthias Rich, ISA Certified Arborist


Emerald Ash Borer                                                                                        


The Emerald Ash Borer (EAB) is one of the most devastating pests that North America has seen in the past 100 years.  It was imported via shipping materials into the Midwest area from China, and it causes damage to ash trees including green, black, white, and blue ash.  The EAB bores into the tree through the bark and lays eggs, and the larvae eat the tree's tissue under the bark, which quickly kills the tree from the top down.  Many people think their tree is alright because it is still green below the canopy, but they often find their ash tree is dead the following year.  There is no question whether the EAB will find your tree or not, it is only a matter of time.   

The EAB is moving southward from its original landing place in Michigan at a rate of several miles per year.  The insect is most active from June to late August, and it is prevalent in the Indianapolis area.  

Signs of EAB 

  • Branches die back from the top down.  
  • Bark can peel off the tree.  
  • Small "D" shaped holes appear in the tree.

Two Treatment Options for EAB

  • Have a certified arborist remove your tree.  
  • Use preventative treatments for your ash tree with insecticides. 

Three Chemical Choices

  • The first method is called a soil drench.  
  • Basal trunk application is the second option.
  • The third and preferred method is a chemical trunk injection.    

​A factor to consider when applying insecticide is the effectiveness of each application.  A soil drench has inconsistent results.  Trunk applications are found to be more effective than soil drenches but less effective than trunk injections.  Their effects are known to last for 6 week, so timing is important. Trunk injections are more effective and they tend to last up to two years.  While this treatment can be expensive, it lasts longest, and you won't have to worry about chemicals coming in contact with people or animals.

Ash trees are beautiful trees that truly enhance the quality of your landscape.  It is a personal decision how you go about protecting your ash trees and there are many options available to you.  The EAB are here and it may be several decades before they move on to another area.  You can lessen the impact EAB has on the ash tree population, but you need to start monitoring your trees and come up with an action plan today.  

Image Credits: Cover, by US Dept of Agriculture on; Top, by US Dept of Agriculture on

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