CO-Horts

CO-Horts

Tuesday, June 14, 2016

Help Slow the Spread of Emerald Ash Borer

By Carol O'Meara, Boulder County Extension

In the two seasons since detection of the Emerald Ash Borer in Boulder, experts have learned that it’s very difficult to find.  The Colorado EAB Response Team, arborists, and foresters have been looking high and low throughout the Front Range, into tree canopies and on the ground at firewood, trying to find the destructive pest.  For a time, the only place that bug was detected was in the city of Boulder.

But that changed last Monday, June 6, when Bodhi Tree Care Arborist James Young saw the classic symptoms of the Green Menace:  D-shaped exit holes and serpentine galleries just under the bark on an ailing ash tree in Longmont.  He also found one of the bugs half in, half out of the ash, killed as it was emerging from the branch. 
Young notified Ken Wicklund, City of Longmont Forester, who went to inspect the tree.   In the warmth of the day, Emerald Ash Borer adults – half-inch long, metallic green beetles – were flying around the tree.  Wicklund contacted the Colorado Department of Agriculture for confirmation identification, which, sadly, was positive.

At the same time the insect was found in a new Colorado community, our neighbors in Nebraska announced the first detection of the pest, making their state the 26th to have the tree killer.  The speed of the spread – to 26 states since it’s detection in Michigan in 2002, killing hundreds of millions of ash – causes any tree lover to weep in dismay.
As you ponder the decimation of a native North American tree, consider also that complicit in this is humans.  The insect arrived here because humans brought it over from its native Asia.  It was by accident but, like opening Pandora’s Box, the damage was done. 

The insect doesn’t naturally spread more than about 1-and-a-half miles per season; for it to leap across the Great Plains or even across our county took humans, moving it in firewood, nursery stock, or shipping pallets.  Once infested wood arrived, the insects ventured out into surrounding areas, attacking ash trees.  By the time the bug is detected it can be miles away from the original source of the infestation.
This is why Boulder County is quarantined; the EAB Response team is trying to slow the spread.  No firewood or any ash wood can be taken out of the quarantine.  It will take all of us to do this.

Owners of ash trees near or within the detection sites of Boulder and Longmont should make a plan for what they want to do for their ash.  Protection with pesticides, removal, or replacements with saplings of a different type of tree is a personal decision each tree owner should weigh, because the Emerald Ash Borer kills trees in a scant handful of years.  The Boulder County EAB webpage offers information on all aspects of what you need to consider (bouldercounty.org/property/forest/pages/eab.aspx).
To aid in your decision, the Colorado State Forest Service has a Decision Guide that walks you through the process (bouldercounty.org/doc/parks/eab-decision-guide.pdf).   Be sure to assess the health of the ash when considering protecting it; not all trees are healthy enough to save. 

For the most accurate tree health assessment, hire a pro.  Certified Arborists are trained to look for symptoms of EAB and many other pests, be they insects, disease, or environmental problems.  They can climb the tree to take a close look at it.  Find a Certified Arborist through the International Society of Arboriculture (ISA) or look for an accredited company by the Tree Care Industry Association (TCIA).
And don’t move firewood or ash wood around.  This will help slow the spread of the Emerald Ash Borer.

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