Emerald ash borer (EAB) is considered the most destructive urban forest pest ever seen in North America. Ash trees are approximately 15-20% of Colorado’s urban forest, which means EAB poses a serious threat. Emerald ash borer was first confirmed in the City of Boulder in September 2013. Most recently the Colorado Department of Agriculture confirmed new detections in Boulder County. The infested trees are near the first confirmed detection site. The Colorado Department of Agriculture believes “the new locations are most likely detections of previous infestation, as opposed to further spread of the insect…but we do expect to see some additional spread this summer within the City of Boulder. ”.
Emerald ash borer can be difficult to detect and it can take multiple years for the infestation to be discovered. It is important to know how to identify an ash tree in addition to knowing the signs of emerald ash borer. Typical emerald ash borer symptoms can include:
- Thinning of leaves and canopy dieback starting at the top of the tree
- Serpentine or “S” shaped tunnels underneath the bark and vertical splits in bark
- D-shaped exit holes in the bark, about 1/8 inch wide
- New sprouts coming from the trunk or roots
- Woodpecker activity
If you notice any of these symptoms or believe your ash tree is infested, contact a certified arborist immediately. The Department of Agriculture will continue to enforce the quarantine in Boulder County and surrounding areas to help prevent the spread of EAB. Remember not to transport firewood or other parts from ash trees.
If you have any questions about emerald ash borer or believe you may have an infested ash tree, ask a Swingle expert.