Emerald Ash Borer

EAB Identification and Reporting | EAB Frequently Asked Questions | Options for Safe Handling of Ash-Tree

EAB Quick Guide | Diagnosing EAB and Other Ash Tree Damage

July 20, 2019, EAB adult confirmed in Broomfield CO; this is the first detection outside current quarantine boundaries, August 29, 2019. EAB detected in Westminster, September 25, 2019, EAB detected near Berthoud.

Emerald Ash Borer Detected in Larimer County near Berthoud

Emerald Ash Borer Detected in Broomfield

Emerald Ash Borer Detected in Superior

New app for ash tree ID

Watch your Ash!

Watch Your Ash is a multimedia project from graduate students at the University of Colorado providing an excellent overview of EAB detection and management in Boulder.

Managing Emerald Ash Borer: Decision Guide


Emerald Ash Borer (EAB) was found in Boulder, CO, in September 2013. As a non-native insect, EAB lacks predators to keep it in check. EAB only attacks ash trees in the genus Fraxinus (so mountain ash are not susceptible). 

Approximately 15% of the trees that make up Colorado's urban forest are ash. There are an estimated 98,000 in the city of Boulder alone.  The Denver Metro area has an estimated 1.45 million ash trees. EAB is responsible for the death of millions of ash trees in the United States.

Help protect Colorado's ash trees! Don't move firewood, and consider chemical treatments to protect high-value ash trees within or near the EAB Quarantine area. 




Contact the EAB Program

The Colorado Emerald Ash Borer Response Team