Save Your Ash - Protect Against Emerald Ash Borer

First discovered in the United States in 2002, the Emerald Ash Borer (EAB) was found in Minnesota in 2009. The Minnesota DNR states, “The state has more than 1 billion ash trees, mostly in forests, while 1 in 5 trees in Minnesota’s communities is ash”.  In early 2020, the MN DNR, selected some 25 communities to share $1 million for tree removal, replacement and some that were treated. 

Emerald ash borer likely arrived in the United States on solid wood packing material carried in cargo ships or airplanes originating in its native Asia sometime in the mid 1990’s. This beetle has been steadily moving through our nation’s forests and has destroyed hundreds of millions of Ash trees.

Adult EAB on a penny 

EAB Facts: 

• It feeds only on ash trees. 

• Has no natural predators. 
• The adult is a slender, bright green, ½ long beetle. 
• It lays its eggs on the bark from mid-May through June.  
• Larvae burrow into the tree, feeding just under the bark from late summer to fall, making serpentine tunnels that are visible if the bark is removed. 

EAB larvae Photo by Jeffrey Hahn, U of MN 

• The tunnels disrupt circulation within the tree and eventually kill it.  
• Larvae overwinter and pupate within the tree, emerging the following spring through D-shaped holes. 

Adult EAB in it’s D shaped hole 

The first year there are few visible symptoms. In the second and third years, the crown thins and the bark cracks over the tunnels. 

 Canopy die-back progression 

• The tree usually dies the third year after infestation.  

• Once the tree’s circulatory system is damaged by EAB, it cannot be repaired, that’s why prevention is so important.  
• There are about 870 million ash trees in Minnesota, one of the largest concentrations of ash of any state. Not only are these trees abundant in our forests, but they are also an important component of our urban landscapes. 

Protect your Ash:  

•  Gertens recommends Bonide Tree and Shrub Insect Control to protect your ash from EAB. 

• Bonide Tree and Shrub Insect Control is mixed with water and then used to water the tree at the base.  
•  GreenLight Tree and Shrub insect control is a granular that you spread at the base of the tree. The tree then absorbs the insecticide and uses it against insects in much the same way antibiotics work against bacteria in humans.  

Each of these products is a simple, once per year application. You can apply prevention in the spring, summer and effectively in the fall too. 

Get started on tree replacements. The Gerten Experts suggest:  

•  Acer, Maple 
• Betula, Birch 
• Ulmus, Elm 
• Tilia, Linden 
• Celtis, Hackberry 

• Gymnocladus, Kentucky Coffee Tree 
• Ginkgo 
• Among many others 

Additional information is found at the University of MN Extension here. Many agencies are continuing efforts to combat EAB in multiple ways, such as biological control including using stingless wasps. If you think you have seen evidence of an EAB infestation, please report it to Arrest the Pest (link sends email), or call 888-545-6684. 

The experts at Gertens are always available to answer your questions!