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Colorado State Forest Service News

Free App Launched to Help Homeowners Determine if Trees Susceptible to Emerald Ash Borer

EAB identification appFORT COLLINS, Colo. — To help Colorado homeowners determine whether trees on their property are susceptible to being killed by emerald ash borer (EAB), today the Colorado State Forest Service and Colorado State University Extension released a free app that will allow anyone to use their mobile device to quickly ascertain whether a tree may be a potential target for the pest.

EAB is a highly destructive, non-native insect from Asia, first detected in Colorado in 2013, which is fatal to all infested ash trees unless the trees have been chemically treated.

“The most important thing Colorado communities can do now is prepare for emerald ash borer’s arrival by increasing their EAB awareness, sharing information about how to identify ash trees and learning the symptoms of this pest,” said Keith Wood, CSFS community forestry program manager.

The EAB/Ash Tree ID app can be downloaded on almost any modern Apple or Android-based device, and easily located in app stores by simply searching for “ash tree.” It offers a step-by-step process to determine if a given tree appears to be a true ash or not, and offers links and other information about EAB for users who suspect they might have an ash tree. The app is intended not just for homeowners, but also for business owners, school groups or anyone concerned about the potential impacts of this pest.

The app also is intended to prompt homeowners and other landowners to consider early management options for EAB. These may include replacing unhealthy trees before they die, treating high-value trees with the proper insecticides and planting new trees near ash that might ultimately succumb to the pest.

EAB, which is responsible for the death of tens of millions of ash trees in 30 states and two Canadian provinces, has only been detected in Boulder County within Colorado. Yet the pest has become a concern for communities all over the state because each year it can fly up to a half mile to infest new trees, and spread much faster through the human transport of firewood and other raw wood. An estimated 15 percent or more of all urban and community trees in the state are ash, which are susceptible to EAB.

Boulder and Longmont have been dealing with the pest’s impacts since having confirmed detections, while many other Colorado communities are preparing for EAB’s arrival. The City of Denver began its “Be a Smart Ash” campaign last year to raise awareness of the EAB threat in the metro area, where one in six trees are ash, and since then has been implementing a 15-year plan to identify, treat and replace ash trees on city property.

For more information about ash tree identification, the symptoms of EAB and treatment options, go to For current information about EAB in Colorado and EAB quarantine information, visit

A screenshot from the new EAB/Ash Tree ID appEAB: What Coloradans Need to Know

Learn how to identify true ash trees:

  • compound leaves with 5 to 9 leaflets
  • leaflets, buds and branches growing directly opposite from one another
  • diamond-shaped bark ridges on mature trees

Know the signs of EAB infestation in ash trees:

  • thinning of leaves and upper branches and twigs
  • serpentine tunnels produced by larvae under the bark
  • D-shaped exit holes 1/8-inch wide
  • new sprouts on the lower trunk or lower branches
  • vertical splits in the bark
  • increased woodpecker activity

Multiple EAB management strategies exist for homeowners and communities, including monitoring trees for the early presence of the pest, removing and/or replacing ash trees, protecting trees with insecticides and planting different species of trees nearby in an effort to get them established before the arrival of EAB.

If hiring someone to apply pesticide treatments to protect ash trees, the applicator must be licensed by the Colorado Department of Agriculture as a Commercial Pesticide Applicator.

Never transport firewood or other products from ash trees, as this is the most likely method of accidental spread. A quarantine is now in place in Boulder County and surrounding areas to try and prevent the human-assisted spread of EAB.

If you think you have detected EAB in your ash trees, please contact the Colorado Department of Agriculture at 888-248-5535 or email

The Colorado EAB Response Team is comprised of members from the following agencies/organizations: Boulder County, City of Boulder, Colorado Department of Agriculture, Colorado State Forest Service, Colorado State University Extension, Colorado Tree Coalition, Green Industries of Colorado, University of Colorado, USDA Animal and Plant Health Inspection Service and various Front Range municipalities.

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