-Emerald Ash Borer (Agrilus planipennis; EAB) is an insect native to Asia and introduced into North America sometime during the 1990’s. Since its initial discovery in Michigan in 2002, this insect has killed millions of ash (Fraxinus spp.) trees throughout the central and northeastern United States and Canada. It is now considered the most destructive tree insect pest ever to be introduced into North America. An Infestation was detected in the city of Boulder in September 2013.
Approximately 15% of the trees in Colorado’s urban forests are ash, making this insect a major threat to urban forests statewide.
Signs & Symptoms
Many ash trees in Colorado are drought stressed and planted in alkaline soils. Determining an emerald ash borer presence is often difficult to the untrained eye. Symptoms include: sparse leaves or branches in the upper part of the tree; vertical splits in bark possibly showing S-shaped galleries underneath; increased woodpecker activity; miniature leaves at the tips of branches late in the summer.
The entire City of Boulder was presumed infested at the close of 2015.
Emerald Ash Borer was confirmed in the City of Lafayette in 2017.
Emerald Ash Borer was confirmed in the cities of Lyons and Superior in 2018.
Emerald Ash Borer has been confirmed in the cities of Boulder, Gunbarrel, Longmont, Lafayette, Lyons and Superior.