Emerald Ash Borer Survey
Emerald ash borer (EAB) is a very serious pest of ash trees. It was found in
Boulder, Colorado in the fall of 2013.
What does EAB do?
- Kills ash trees!
- Larvae feed under the bark, eventually
girdling the tree and cutting off nutrients.
- Ash trees are killed
within 2-4 years of first symptoms, even previously healthy trees.
- Ash trees of all size can be attacked, from 1/2 inch saplings to largest
- This insect is very difficult to detect because it is
under the bark and the adults are only around from May to September.
How did EAB get here?
Infestations result from movement of infested ash trees and wood. The
insect does not fly far from its own. Some of the items it moves on or in:
- Packing material/industrial wood material
- Live plant material (nursery stock, etc.)
- Ash wood such as logs,
branches, chips, etc.
What can I do about this pest?
- Determine if you have any ash trees on your property. True ash trees have compound leaves with 5-9 leaflets, and buds, leaflets and branches grow directly opposite from one another. Mature trees have diamond shaped bark ridges.
- Use a new free app to assist with the identification process. The Colorado State Forest Service and Colorado State University Extension have developed EAB/Ash Tree ID App for both Apple and Android devices. Simply search the app store for “ash tree.”
- Watch for symptoms, which include branch dieback near the top, D-shaped exit holes 1/8-inch wide, serpentine tunnels under the bark and new sprouts on the trunk and branches.
- Evaluate whether chemically treating a tree is worthwhile. Large, high-value healthy trees might warrant early treatment as “insurance” much more than young, unhealthy or poorly located trees. If you hire someone to apply pesticide treatments to protect ash trees, make sure the applicator is licensed by the Colorado Department of Agriculture as a commercial pesticide applicator.
- Consider removing or replacing ash trees before the pest’s arrival and planting diverse new tree species. This can offer more long-term benefit than paying for preemptive chemical treatment in areas where the insect has not yet been detected.
- Know that treatments exist that are capable of helping infested trees recover if applied early in an infestation.
- Never transport firewood or other products from ash trees as this is the most likely method of accidentally spreading the pest.
For more information visit the
Contact the Colorado Department of Agriculture at 1-888-248-5535 or email CAPS.firstname.lastname@example.org.