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Should you protect your Ash Tree from the Emerald Ash Borer in Denver?

Since the Emerald Ash Borer has landed in Colorado, a lot of people are asking us if they need to take preventative measures to protect their Ash Trees. Not all trees need to be treated, here is a great diagram from Colorado State Extension with good tips on how to decide if you should treat your trees, if you can do it yourself, or if you need to call us for a treatment.

Managing Emerald Ash Borer – A Decision Guide:


Emerald Ash Borer

What are the Emerald Ash Borer treatment options?

Homeowners can protect healthy Ash trees if:

  • The trunk less than 15 in. Diameter at Breast Height (see diagram above)
  • With over the counter soil drench products. One option are products containing 1.47% imidacloprid. These products are most effective when applied between May 1st and June 15th. Disclaimer: Over the counter formulations are not as strong as professional formulations and are not advised to be used on trees with a DBH of greater than 15 inches.

Professionals can protect ash trees:

  • With a trunk greater than 15 in. DBH.
  • Later in the year, using specialized equipment to apply insecticides that contain imidacloprid, dinotefuran, azadirachtin or emamectin benzoate.

Ash Trees CAN be saved if they are:

  • Healthy and vigorously growing, with more than half their leaves.
  • Enhancing the landscape.
  • Valuable to the owner.
  • Showing only few outward signs of EAB infestation.

Ash Trees should NOT be saved if they are: 

  • Unhealthy, with dead branches and more than half of their leaves missing.
  • Planted in poor sites or are not important to the landscape.
  • Showing many outward signs of EAB or other insect infestation (click here to view other wood boring insects that target Ash Trees), such as woodpecker damage, bark splits, and water sprouts at the tree base.

Contact us today if you have any questions about the Emerald Ash Borer.
Call us at 303.232.0666 or send us an estimate request below:
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