The City’s phased plan to reopen facilities and services is based on our commitment to protect City staff and residents, and in adherence with the most up-to-date State of Colorado and Boulder County public health orders. To learn more about which City facilities have reopened or plan to reopen, visit the COVID-19 webpage.

Emerald Ash Borer Information

Press Enter to show all options, press Tab go to next option

Emerald Ash Borer Information:

The Emerald Ash Borer (EAB) is a wood boring beetle that is an emerging threat to all North American species of ash.  This insect was accidently introduced to North America from Asia, most likely sometime in the 1990's.  EAB has already killed millions of ash trees and will likely end up killing all unprotected ash trees that it invades.

An EAB infestation was confirmed on the University of Colorado campus in September 2013.  This location is within 5 miles of the City of Louisville.  Treatment within a 5 mile radius of an infestation is recommended if the owner(s) elect to implement control measures.  Most likely, EAB is already present in the City of Louisville, but we just haven't found it yet.  Fortunately, the numbers are still very low with only a handful of trees infested.  Sampling of suspected trees will be conducted spring 2014, and program implementation will be amended as necessary. Staff estimates the City has a total population of 123,000 trees, approximately 18,000 are ash.  Out of the 18,000 ash trees, 1,000 are on public property, the rest are on private property.

Staff recommends only treating public trees that are considered high value.  High value ash trees would be of substantial size, located in parks or other prominent locations, are relatively free of insect, disease, and wounds, and possess good structure.  Out of the 1,000 ash trees approximately 20% are classified as high value trees.  Staff recommends insecticide trunk injections as the control option for treating the high value trees.  Staff recommends using a chemical by the trade name TreeAzin for the injections.  The extended cost ranges from $5 to $18 per diameter inch and is dependent upon number of treatments and whether applied by City staff or out-sourced.  This is an organic labeled product.

EAB and the City's approach have been discussed at Horticultural and Forestry Advisory Board (HFAB) meetings. HFAB is in agreement with this approach, expending resources only on high value trees.

The City's Branch Recycling site meets regulatory requirements for any required quarantine procedures related to EAB. EAB will not impact Western Disposal's curb-side composting program.  Assuming EAB will become more invasive means that the situation is dynamic and information will evolve as we move forward.  Colorado State University Extension Services is the "go to" institution for extensive information on

EAB as they have some of the most highly regarded entomologists in the nation. 


If you have questions, please contact the City Forester Chris Lichty, 303.335.4733.

Free viewers are required for some of the attached documents.
They can be downloaded by clicking on the icons below.

Acrobat Reader Download Acrobat Reader Flash Player Download Flash Player Windows Media Player Download Windows Media Player Microsoft Silverlight Download Microsoft Silverlight Word Viewer Download Word Viewer Excel Viewer Download Excel Viewer PowerPoint Viewer Download PowerPoint Viewer