CO-Horts Blog

Monday, May 5, 2014

Assessing Ash risk

Posted by: Carol O'Meara, Boulder County Extension

In the months following the detection of Emerald Ash Borer in Boulder, people have been holding their breath, waiting for word on where the pest would show its presence next. They’re gazing at their ashes, appreciating what they have that might, in a short time, be gone.

Advertisements by mail or on the radio make the situation seem dire (one announcer sounds as though he’s shaking with rage that the insect dared come to Colorado). If you’re wracked with indecision on what to do to protect your ash or when to do it, take a deep breath and relax before making your decision.

Distance from the detected pest is the first question to answer; in Colorado CSU Entomologists recommend that only those ashes within five miles of the bug need protection. If you live further away than five miles from the pest, you have time to plan before booking tree treatments.

Check how close you are to the five mile zone by clicking on the Ash Tree Management Zone Map. There, you can type in your address and the map will zoom in to your location and identify the risk zone you live within.

Then build a plan, starting with an assessment of your trees and whether they’re healthy. Not all ashes are healthy enough for treatment; should they have greater than 40-percent dieback of their canopy they won’t translocate treatments effectively through the tree. Small trees could be protected, but ask yourself if it would be better to remove and replace them with another tree type. Often, costs of treatment far outweigh the costs of replacement.

Next, assess the type of treatment you would like for the tree. Small trees of less than 15-inch diameter can be helped with products you can purchase and apply yourself. But be careful – these products contain pesticides harmful to bees, so make sure there are no blooming plants, wanted or unwanted, in the ground under the tree (especially dandelions).

If your tree is larger than 15-inches or you’d like options that are more bee-friendly, ask your tree care company to help you in your decision. Don’t be alarmed by radio ads – heavy with reverb – announcing the presence of the pest. Arm yourself with the facts by going to and scroll down to How to Manage EAB and click on control options for information on the available treatments.

1 comment:

  1. Excellent, concise information! We thank you. I am forwarding it to one of my neighbors this evening...