Emerald Ash Borer Taking Toll On Ash Tree Population
Emerald Ash Bore is methodically wiping out the ash tree population in Glenwood and Mills County.
Beginning this week, 27 dead or infected ash trees are being cut down at the Glenwood Cemetery and that’s just a fraction of the infected trees in the city.
The wood-boring beetle, whcih was first detected in Mills County about four years ago, is now making an all-out assault on ash trees in the Glenwood area.
“If a tree (ash) hasn’t got it in Glenwood, it will,” said Don Duysen, owner of Duysen Nursery and a member of the Glenwood Tree Board. “It’s all over Glenwood. All you have to do is look for it and you’ll see it everywhere.”
Duysen said the first official Emerald Ash Borer confirmation in Glenwood was made by a representative of Iowa State University at the baseball and softball field on South Vine Street.
“A piece of tree fell to the ground,” Duysen said. “He took his blade over to it and there they (beetles) were.”
Duysen said he and fellow tree board member Tom Hoogestraat took a drive around Glenwood and identified over 100 trees in Glenwood that had succumbed to Emerald Ash Borer and dozens more that had likely been infected. Ironically, many of the ash trees in Glenwood were planted in the 1950s, 60s and 70s as replacements for trees that had died from Dutch Elm Disease.
Emerald Ash Borer is an invasive pest from Asia introduced to the United States in 2002. The beetle was found in shipping pellets sent to Detroit, Mich., and Ontario, Canada. It quickly spread into neighboring states in the upper Midwest and eventually across the U.S. and Canada.
The adult Emerald Ash Borer is a small, metallic green beetle about 10-15 millimeters in length and 3 millimeters in width. The larvae reside under the bark of the tree. Adults typically emerge in late spring or early summer, leaving D-shaped exit holes in the bark. The beetle feeds in the canopy of the tree for awhile, with the female reproducing and laying eggs in crevices of the bark.
Duysen said preventative treatment for Emerald Ash Borer consists of injecting a tree with an insecticide.
“It’s a two-year residual,” he said. “It’s $12 every four inches. An average tree would cost right around $175 to treat, but it’s good for two years.”
Duysen stressed that the injections can’t save a tree that’s on its way to dying.
“If it’s over 30 percent gone, then it’s not worth saving it,” he said.
Only ash trees are affected by the ash borer so trees that are cut down can be replaced by other species, such as elm or maple. Replacement trees shouldn’t be planted too close to where the ash tree had been planted.
“Depending on the size of the tree, when you cut a tree down, you still have the root system under there,” Duysen said. “You have to move off at least 10-15 feet away from that tree.”
Glenwood Cemetery sexton Mike Collins said many of the trees infected at the cemetery are around 25 years old. Collins noted that the situation is similar to when the cemetery lost several pine trees around a decade ago because of a pine bore infestation.
Collins said it will take several weeks for all of the infected ash trees to be removed. Cemetery workers are cutting down most of the trees, but a contractor will be needed to take down some of the largest ones.