Emerald ash borer detection efforts continue over winter

Although the tree-killing emerald ash borer remains dormant over the winter months, the interagency team working to manage the pest in Colorado is not.

Over this fall and winter, the Colorado EAB Response Team – comprised of the Colorado Department of Agriculture, USDA Animal and Plant Health Inspection Service, Colorado State Forest Service, Colorado State University Extension and other partners – is assisting Front Range communities in their efforts to detect the presence of EAB, through branch sampling efforts and peeling “trap trees” to seek out the overwintering, larval stages of EAB before they emerge as adult insects in the spring. Trap trees are ash with bark rings previously removed to intentionally stress the trees and make them more desirable to EAB adults seeking new hosts.

“Emerald ash borer is a notoriously difficult pest to find, particularly during the early stages of an infestation,” said Micaela Truslove, EAB program coordinator, Colorado Department of Agriculture. “Branch samples and trap trees are mechanisms that can help us detect this destructive pest as early as possible.”

Systematic sampling for EAB in Colorado’s ash trees began in Boulder in the fall of 2013. Since then, many other communities have completed some form of branch sampling, including Arvada, Aurora, Centennial, Denver, Greeley, Littleton, Lone Tree, Longmont and Sheridan; also, Boulder County soon will be peeling trap trees it established earlier this year.

Recently, the EAB Response Team has assisted Berthoud, Lafayette, Longmont and Milliken with branch sampling and/or trap tree-peeling efforts, and this January will assist Federal Heights with additional branch sampling. The team also is hosting EAB identification workshops at the City of Boulder Forestry facilities through January, targeting green industry and landscaping professionals.

To date, EAB has not been detected in Colorado outside the City of Boulder. Truslove says the results of any EAB sampling activities that result in a confirmed positive detection outside the city will be made available to the public, and that sampling efforts are ongoing.

“There is the potential for new detections at any time of the year. Communities are out looking, and will continue looking, until EAB is found,” she said.

A non-native pest responsible for the death of millions of ash trees and billions of dollars in costs in 24 states, EAB was first confirmed in Boulder in September 2013. The pest attacks and kills all true ash species, which comprise an estimated 15-20 percent of all trees in the state’s urban and community forests.