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St. Louis Ash Trees, Be Warned: The Emerald Ash Borer Is On The Loose

An adult emerald ash borer.
(David Cappaert, Michigan State University)
An adult emerald ash borer.

Beware the Emerald Ash Borer. 

Ash trees in the St. Louis area are susceptible to attacks from the Emerald Ash Borer, an invasive species of beetle that has been creeping toward the area since 2008.

The green beetle, with a penchant for any kind of ash tree, has infested and killed millions of trees nationwide. The beetle is native of Asia and was first found in Michigan in the early 2000s, although recent research suggests the bug could have been here since the early 1990s.

It was first spotted in Missouri in Wayne County in 2008. Since then, it’s spread around the state and has been identified in Perry County, which is only about 50 miles south of St. Louis. Perry County is also where a lot of people in St. Louis get their firewood. That’s important because scientists believe the Emerald Ash Borer hitches rides on transported wood.

“Firewood transportation is how it has spread so readily,” said Karl Dreyer, district manager for Davey Tree Expert Company. Rather than rely on the natural flight mode of the insect,which is only a few hundred yards at a time, the borer travel from woodlots, to campgrounds, and from campgrounds to homes, Dreyer said.

“How it originally got there, no one knows.  It could have been transported in bundle of firewood, from Michigan, Ohio, Minnesota. Someplace where it had already been established,” Dreyer said.

It’s not the adult beetle that kills the trees. The small, green metallic bug only nibbles on leaves. But the bug's larvae bore their way into the trees, creating S-shaped galleys that eventually kill the tree.

Dreyer said the beetle is most active in the summer, so people should create a plan of action now to prevent the Emerald Ash Borer from destroying trees.

“Woodpecker activity, chewing damage on the edge of leaves, v-shaped holes, bark splitting, canopy die-back, multiple sprouts on the trunk, those are some of the symptoms," Dreyer said. "Preventative care is the best way to protect the trees. Treating the trees is a lot less expensive than replacing the tree.”

Dreyer added that most evidence of the Emerald Ash Borer is found fairly high up in the canopy, which is why hiring someone to inspect your trees the safest way to know if your trees are infested.

Another way to protect your trees from infestation is to make sure that you have a variety of species in your yard. A lack of diversity was the problem at the St. Louis Arch grounds, which had to replace all 900 of of its ash trees. Dreyer said, mixing up the kinds of trees on the Arch grounds -- or in someone's backyard -- helps prevent the spread of any kind of disease or infestation, and makes the trees healthier.

Shula is the executive editor at St. Louis Public Radio.