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Emerald Ash Borer

Emerald Ash Borer has infested parts of Colorado but currently has not been found in the Pikes Peak Region. Emerald Ash Borer (EAB) came to Colorado from the Midwest through firewood being transported. It has spread across 22 states in the U.S. and has killed millions of ash trees since 2002 while threatening many more. Unfortunately, EAB does not have immediate predators to keep it under control. According to the Colorado Government, ash trees make up about 15 percent of Colorado’s forest.

Emerald Ash Borer

The EAB attacks both healthy and unhealthy ash trees and then destroys them by cutting off water and nutrients that the tree needs to survive. It takes around 4 -5 years after the first attack by the EAB before the ash tree dies from a drought-like cause.

Infestation Symptoms

There are a few signs to look out for if your ash trees are infested with EAB. However, it’s important to remember that it could take about 3 to 4 years of EAB infestation before you are able to see a decline in the health of your trees.

  • Sparse Leaves or Branches on Upper Part
  • Vertical Splits in the Bark
  • S-shaped tunnels under the bark
  • D-shaped exit holes
  • Increased woodpeckers
  • EAB on leaves

Ash Trees

EAB only infect true ash trees. To know if your trees are ash trees, you can look at the branches to see if they are directly across from each other, the leaves have 5-11 leaflets, the bark has a distinct diamond shaped ridges for mature trees and relatively smooth for younger trees. To further identify if you have ash trees on your land you can check out this site .


One of the things homeowners can do to protect their ash trees is to soil drench them with imidacloprid. Soil drenching can only be effective when applied between May 1 – June 15. If trees are healthy and have more than half of their leaves growing, with only a few signs of EAB infestation, the tree can still be saved. Ash trees that have dead branches with half of their leaves missing are in a very unhealthy state and will most likely not be saved. Other damages from woodpeckers, bark splits, and insect infestation is another indication that the trees cannot be saved. If the tree is infested more than 30% of crown dieback, the tree should be removed to ensure the EAB does not spread.


To learn more about EAB and how to protect your ash trees, contact Front Range Arborists. We have been the full-service Colorado Springs tree and shrub care company since 1984. We are here to answer all your questions as we strive to provide quality tree, shrub and turf care in a safe, professional manner.

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