JOHNSTON, Iowa - As the Emerald Ash Borer makes its way from Eastern to Central Iowa, cities across the Metro are taking preventative measures to save as many of its Ash trees from the non-native insect as possible.
Wednesday, the City of Johnston Parks Department began treating 60 ash trees throughout its greenbelts and parks with a systemic insecticide injected directly into the trunk of the tree. The trunk injections are absorbed and distributed throughout the tree within one to four weeks and kill any Emerald Ash Borers feeding on the trees leaves, as well as any larvae inside the trunk of the tree. City officials say research has proven this method to be highly effective in combating the insect.
The Emerald Ash Borer is considered to be one of the most destructive tree pests ever encountered in North America. An exotic insect from Asia, the Emerald Ash Borer has already destroyed hundreds of thousands of trees across the U.S. by colonizing the top of the ash tree and moving down over time, leaving larvae that feed below the bark of the tree and cut off the flow of nutrients. If affected, an ash tree will surely die and must be cut down.
Approximately 18 percent of Johnston's trees in public spaces are ash trees, according to information on the city's website. The density of these trees is even higher in several neighborhoods, estimating a severe physical and financial impact on these areas if all the trees are lost.
"We've been anticipating the arrival of the Emerald Ash Borer for years, after seeing it take over in Southeast Iowa," said Tracy Irwin, the Urban Forest Crew leader for Johnston.
Irwin says, while they can do their best to prevent Emerald Ash Borer infestation in ash trees in the city's public spaces, they can't completely eliminate the loss of ash trees.
"There are some native trees, like in our woodlands. You know, you can't treat every tree, so it's not only trees in the towns or in the parks, but it's also trees out in the wood lots that we're going to lose - left untreated," he said. "And you know, there's just so many of them."
However, Irwin says it's much cheaper for the city to invest in preventative treatment such as this, than to let the trees die and pay to remove them all after. The Johnston Parks Department says it's happy to help you if you have an ash tree on your private property.