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Colorado gives up fight against emerald ash borer

Wednesday, September 18, 2019   (0 Comments)
Posted by: Beth Farmer
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The state of Colorado is abandoning its six-year effort to contain the spread of the emerald ash borer (Agrilus plagripennis), an invasive pest that kills ash trees, according to a report by the Colorado Sun reader-supported journalism site. The state plans to cancel its quarantine and allow the unrestricted movement of firewood, mulch, lumber and other wood products.

Although quarantines normally are intended to eradicate a pest, Colorado’s emerald ash borer quarantine was intended to slow the pest down, buying time to replant urban forests with replacement trees. Officials said it accomplished its purpose. They recommend that users continue the transition to other trees in the landscape, as the emerald ash borer attacks only ash.

The pest’s larvae destroy the vascular systems of ash trees, killing them. It arrived in North America from Asia, likely via wooden shipping crates, and was first identified in Michigan and Ontario in 2002. Colorado so far is the westernmost state where the pest has been confirmed. It’s been found in every state and Canadian province east of Colorado, except for North Dakota, Mississippi and Florida.

It is possible to treat ash trees for the pest using systemic pesticides, but best to treat them while healthy so the chemicals can circulate throughout the tree. Four universities published a guide to treating for emerald ash borer (PDF) this past spring.

The search for ash tree replacements was featured in the August 2017 edition of Digger, published by the OAN.