Emerald Ash Borer Found in Colorado Front Range Trees: Denver-based Swingle Issues Service Advisory

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Reports of Emerald Ash Borer being found in Colorado trees has generated concern in Denver and along the Front Range. Swingle advises what services are best and when.

Denver Tree Service - Emerald Ash Borer in Colorado - Swingle

Emerald ash borers are a bright, metallic-green color. They are approximately ½” long and have a flattened back.

The emerald ash borer is here, the threat is real. Responsible tree owners will contact an expert immediately.

Denver and Fort Collins offices of Swingle Lawn, Tree & Landscape Care have learned that Emerald Ash Borer has been found in trees on Colorado’s Front Range. Emerald Ash Borer is now considered the most destructive forest pest ever seen in North America.

“The insect is aggressive and will infest all untreated ash trees in its path, killing them within a few years,” said Swingle owner and CEO Tom Tolkacz. “It has destroyed hundreds of millions of trees in the upper Midwest and eastern United States.” The insect was first confirmed in Boulder on September 26, 2013.

Ash trees are identifiable by compound leaves with five to eleven leaflets and branches and buds in pairs directly across from each other (opposite branching). The bark of mature ash trees has diamond-shaped ridges.

Initial detection of Emerald Ash Borer in ash trees is difficult. Signs of infestation include:

  • Canopy dieback, beginning at the top of the tree and progressing downward
  • In later stages of infestations, ash trees may form sprouts from the trunk and roots.
  • Bark can split, exposing “S”-shaped galleries underneath.
  • Adult beetles leave a “D”-shaped exit hole in the bark, roughly 1/8 inch in diameter, when they emerge.
  • Woodpecker activity and damage increases where they are trying to get to the larvae in the tree.

It may take up to five years for the canopy of an infested ash to thin and decline. Since borers infest the upper branches of the tree, the “D”-shaped holes cannot be seen from the ground until the tree is severely infested.

To mitigate the damage to Colorado trees, Swingle strongly advises the following actions and services for homeowners and property managers:

  • First, consult an expert, such as a Swingle Landscape Care Consultant, to verify ash tree inventory, evaluate the trees for infestation and make custom recommendations.
  • Do not plant new ash trees. Good substitutes for ash include maples, lindens, honeylocusts, hackberrys, oaks and elms.
  • Do not move firewood made from ash trees out of the area.
  • Prune dead branches. Dead branches weaken the tree; an unhealthy tree is much less likely to survive an Emerald Ash Borer attack. This activity is also timely as we move deeper into autumn, as dead branches on trees are a risk of breakage should we experience early winter storms on Colorado’s Front Range.
  • A likely prescription from an arborist is a trunk injection, to be completed in the spring of 2014, within a 15-mile radius of any detected emerald ash borer infestation. At present, this includes communities in Boulder, Lyons, Longmont, Niwot, Erie, Lafayette, Superior, Broomfield, Westminster and Nederland. More immediately, Swingle recommends a soil injection, to be completed in the autumn of 2013, outside any 15-mile detection area.
  • Additional recommendations may include tree fertilization and lilac/ash borer or ash bark beetle spray.

“Ash trees make up 15 percent of the Colorado Front Range urban forest,” said Tolcakz. “In the Denver area alone, nearly 1.5 million ash trees are at risk. The emerald ash borer is here, the threat is real. Responsible tree owners will contact an expert immediately.”

About Swingle Lawn, Tree & Landscape Care
Founded in Denver in 1947, Swingle Lawn, Tree and Landscape Care has grown to be the one of the largest residential and commercial lawn service and tree care companies in Colorado, employing more certified arborists than any other Colorado company. For information please contact Vince Serio VSerio(at)MySwingle(dot)com (303) 337-6200.

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