The Emerald Ash Borer will most likely become the single most destructive pest in Denver’s urban forest history. First discovered in Michigan it has since caused millions of Ash trees to die and billions in losses to municipalities for the treatment or removal and replacement of infested trees. Denver is home to roughly 1.5 million Ash trees which is about 15% of the total tree population. Initial plantings of Ash trees to replace Elm trees throughout the city which had died from Dutch elm disease and were also considered a good replacement tree for elms throughout the U.S. Now that this non-native pest has been introduced, that decision could be second guessed. Populations of the Emerald Ash Borer were identified in Boulder County in 2013 and the spread has been thankfully limited to date. Wood quarantines have been placed on Boulder County and extended to Erie, it is unlawful to remove any Ash wood from the quarantine area and fines may be levied. There will be costs associated with any treatment for the Emerald Ash Borer though the most expensive would be to remove your untreated tree once it had died.
Elk Creek currently offers two different levels of control against this pest for your prized Ash trees. A systemic basal trunk spray will protect the tree for one growing season and will also help to control leaf curling aphids and other boring beetles. This treatment is also recommended for smaller Ash trees up to 8 inches in diameter. The second treatment option provides up to 2 years of protection and will also control other boring beetles. This systemic insecticide is injected into the tree using the Tree-Age I.V. Kit and is only recommended on trees with a diameter larger than 8”. In laboratory and field studies, this treatment provided the best control.
Systemic insecticides and preventative sprays will also help to control theses boring insects in our region: Ash Bark Beetle, Clear Winged Borer, Bronze Birch Borer, Peach Tree Borer, the Round Headed Apple Borer and the European Elm Bark Beetle, just to name a few.