Mequon — In what appears to be the first official sighting of the pest in the city, the emerald ash borer was discovered on several trees in the 14000 block of Granville Road by Mequon Public Works workers April 2.
The trees were promptly removed.
Photographs were taken and sent to the state Department of Natural Resources, which confirmed its presence. The news of the infestation comes as no surprise to city staff in Mequon.
"We have been aware our neighboring communities have been infected," said Kristen Lundeen, acting director of the Department of Public Works. "We knew there was a potential it was here; however, we just hadn't identified it yet."
According to a statement released by the city of Mequon, the trees showed larvae as well as the distinctive S-shaped pattern left by the larvae under the bark when workers examined them before removal.
Emerald ash borer is a metallic-green beetle native to east Asia that accidentally invaded the U.S. in the wood of shipping crates from China, said Wisconsin's Emerald Ash Borer Information Source website.
The larvae kill the ash trees by hiding and eating the tissue under the bark; naturalists have been searching for ways to stop its spread. The borer will not harm humans.
What makes the EAB hard to discover is that females reside and lay eggs in the crevices where branches meet at the tops of ash trees. It takes three to five years for the insect to crawl its way down to places where humans can see it, said Jason Nickels education and restoration director at Mequon Nature Preserve.
The city of Mequon may either treat the ash or cut down trees along the roadsides, parks and sidewalks.
"We are taking steps to begin the treatment of ash trees in our parks and right of ways, said Don Curran, director of Parks and Operations in Mequon. "This process will be ongoing, as will the removal of diseased trees as we find them."
If citizens have ash trees in their yards, Mequon recommends contacting certified arborists who will be able to determine if treatment is required based on how damaged the tree is.
According to University of Wisconsin-Extension Entomology website,"research suggests that insecticide treatments are significantly more effective on EAB-infested ash trees with less than 50 percent canopy thinning. Insecticide treatments are not suggested for trees with greater than 50 percent canopy thinning. Ash trees with greater than 50 percent canopy thinning should be removed and destroyed in accordance with established state and federal guidelines."
Mequon's website also warns citizens to avoid transporting Mequon wood outside of the city in order to slow the spread of the EAB.
Curran stated Mequon plans to treat ash with its own staff this spring. They will also contact companies involved in treating trees for assistance.
"Treating 'all of Mequon' is not really feasible," Curran said. "We will mainly focus on larger specimen trees that are within our own parks and right of ways. A recent survey… equates to the treatment of approximately 4,400 street trees, which will be a long process over the upcoming years."
To celebrate Arbor Day and to aid tree transplantation, Mequon will hold an Arbor Day Festival on Sunday, April 27, at Logemann Community Center. Free seedlings, such as Norway spruce, white spruce, white birch, quaking aspen and American hazelnut will be given away.
One strategy to stave off any one species being destroyed by disease or by insect infestation is to "not plant more than 10 percent of one species," Nickels said.
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