Emerald Ash Borer Beetle Population Expands Exponentially in Fort Collins

The presence of Emerald Ash Borer (EAB), an invasive pest affecting ash trees, was confirmed in Fort Collins in May of 2020. As of July 2024, EAB has been found well within Fort Collins city limits. EAB has the potential to decimate all untreated North American Ash species of the genus, Fraxinus. The City of Fort Collins Forestry Division has been preparing for EAB since its detection in the United States in 2003, and continues to implement treatments based on the EAB response plan.

“This is the first year where dead and dying trees have been very easily spotted in certain areas of Fort Collins, including the W. Plum Street corridor and as far south as E. Horsetooth Road and John F. Kennedy Parkway,” explained Ralph Zentz, Assistant City Forester. “This tells us that the beetle population is expanding exponentially, which is as we expected.”

The Forestry Division has been treating desirable trees on City-owned land on a three-year cycle since 2021. Many Fort Collins residents and Homeowner’s Associations (HOA’s) have also been proactively treating desirable trees on their properties since 2020, or earlier.

Ash trees become extremely brittle in a short period of time once they die from EAB. When trees are infested and beyond the opportunity for chemical treatment, the trees need to be removed in a timely manner for the safety of homeowners, Forestry staff, arborists, and physical property.

Community members are encouraged to develop their own treatment plan as EAB is expected to continue its spread throughout the region. Local arborists can help determine if your property has ash trees, evaluate tree health conditions and assess the costs of treatment, removal, and replacement. A list of licensed arborists can be found online at fcgov.com/forestry/arborists.

For more information on managing EAB, please visit fcgov.com/forestry/emerald-ash-borer.