Emerald Ash Borer (EAB) is a wood-boring beetle that targets ash trees, including green and Autumn Purple ash. Overall, 25 states are known to have EAB infestations, Colorado being the western most. The beetles kill all untreated ash trees within two or three years of infestation. With an estimated 1.45 million ash trees in the Denver Metro area including 50,000 in Littleton, an EAB infestation in the area could be a serious problem.
Emerald Ash Borer was confirmed in Boulder in late September 2013 and the area was quickly quarantined to prevent the movement of any ash wood and trees to surrounding areas. As of July 2017, EAB has not been found anywhere in Colorado other than within the Boulder County quarantine. The hope is that the quarantine and Colorado’s dry climate will slow the spread of the insect and preventative treatments will not be required in the south metro area for a few years. The City of Denver has begun proactively treating, removing, and replanting public trees as a part of its Be A Smart Ash program.
There are several systemic insecticide treatments that have proved successful in preventing EAB infestation. When properly applied to the trunk or surrounding soil, they will keep EAB out of a treated tree for one to three years after which another treatment will be required. Since this prevention method is only recommended for homeowners with individual, high-value ash trees within five miles of Boulder, there is no reason to begin treatment in Littleton at this point.
For now, Littleton residents should identify ash trees on their property and make decisions regarding future treatment, replanting, or removal of these trees in the coming years. The Colorado Department of Agriculture is the lead agency for the fight against EAB. Its website, www.colorado.gov/agplants/emerald-ash-borer, has more information about EAB, help with ash tree identification, and an easy to use decision matrix/guide to managing EAB. The City of Littleton has expanded its spring Tree Program to promote diverse replacement planting to mitigate the impending arrival of EAB. Call 303-795-3766 for specific questions about EAB.