Emerald Ash Borer detected in Colorado county

BERTHOUD, Colo. – On Oct. 2, national and state experts confirmed the presence of the emerald ash borer (EAB)—an invasive, highly destructive tree pest—near the town of Berthoud, in Larimer County. This detection represents the first ever in the county, and the third confirmation of EAB in Colorado outside of a federal quarantine in less than two months.

It is unknown whether this pest arrived in Larimer County by natural spread or via accidental human transport, such as in firewood or other raw ash material. Staff with Larimer County and the city of Loveland recently helped to obtain insect samples gathered near Berthoud, after an arborist brought an ash log containing the insects to the Loveland recycling center. A Colorado State University Extension agent delivered the insects to an EAB expert on campus, who first confirmed it as being the pest; it was then confirmed a second time this week by a national EAB expert in Brighton, Mich.

The infested ash was located on private property in unincorporated Larimer County, less than three miles southwest of Berthoud. Foresters are now in the process of conducting field inspections of ash trees on other properties in the vicinity, to determine the extent of observable EAB infestation.

EAB was first confirmed in Colorado in 2013, in the city of Boulder. Since then, the pest has been confirmed in several other municipalities in Boulder County within the quarantine, as well as in Broomfield in late August, and Westminster in September.

For more information about ash tree identification, the symptoms of EAB and treatment options, go to eabcolorado.com or csfs.colostate.edu/emerald-ash-borer.