The Clinton Herald, Clinton, Iowa

April 21, 2014

Horticulturalists: Infestation of Emerald Ash Borer 'inevitable'

By Brenden West Assistant Editor
The Clinton Herald

---- — CLINTON – Not everyone at the Bickelhaupt Arboretum can remember what happened to local horticulture in the late 1960s. They’ve all heard stories, though, about how Dutch Elm Disease laid waste to scores of trees across the Midwest.

Now another infestation threatens the region. The pest known as the Emerald Ash Borer (EAB) has been found as close as Morrison, Ill. Within the next three to five years, local experts believe the insect will find its way across the Mississippi River, and the looming destruction is expected to “far surpass” what happened more than four decades earlier.

“They think there are eight billion ash trees in North America,” said Margo Hansen, director of programs at the Arboretum. “Back in the 60’s, we used to have these streets that were all canopied by elm trees, and they all died because of Dutch Elm.

“The problem (with EAB) is that it’s real small – smaller than a penny. And once it gets in the tree it’s too late.”

In February, a quarantine was placed on all of Iowa’s 99 counties that prevents moving wood that might be infected, like entire ash trees; firewood of any hardwood species; or any cut or fallen material of the ash, with the goal of slowing the Emerald Ash Borer’s spread.

The Clinton Tree Commission also is beginning a push to inform citizens about EAB dangers. Local agencies have begun implementing procedures they hope will prevent a widespread outbreak.

The borer – a native insect of Asia -- was rumored to be introduced to Michigan in 2002. It has since made a steady migration to the Midwest and upper East Coast. The creature only borrows into ash trees, which are common in the Midwest due to their previous landscaping-friendly nature.

Hansen explained that Dutch Elm Disease was a fungus that grew within trees and blocked water circulation or “clogs the trees’ arteries.” The EAB, instead, borrows into the wood, severing the veins, cutting off water and killing trees over time from the top down.

Once the insect has infiltrated the bark, Hansen said it’s already too late. And the pest’s subtle signs and size make it difficult to detect.

While EAB can only travel roughly a half mile annually, lumber transportation (such as firewood movement) has accelerated the migration. Experts estimate between 30 and 35 percent of all trees in Clinton can be affected.

As more communities have become aware of the problem, the infestation has somewhat slowed. Hansen and others say communication with the community is important.

“If we can get that education across, we can slow it down,” said Randy Pennock, Tree Commission member. “It’s caught up with us, and (infestation) is inevitable, unfortunately.”

Brad Seward at the Clinton County Area Solid Waste Agency said his group has started turning away unwanted ash remnants in order to prevent a potential spread. And the Tree Commission is writing a grant to get a full inventory of trees in order to make recommendations to the Clinton City Council.

“Anytime I get news it’s approaching, I perk up my ears,” Seward said. “We’ve started discussions about how much longer do we sell our yard waste mulch. Are we unknowingly sending EAB back out of our doors?”

Still, nothing will stop what horticulturalists are calling a “tidal wave.” For now, it’s important for homeowners who own ash trees to decide to remove or pretreat their plants.

By making Clinton’s horticulture more diverse, Hansen believes the community can minimize the EAB impact.

The alternative will be scores of dead wood that will be similar to that troubling time of Dutch Elm Disease.

“It’s going to come and people need to pay attention to the news,” Hansen said. “Information is going to change as we progress.”

Pennock added tree owners should closely monitor their ashes. The EAB leaves a penny-sized, D-shaped hole in the wood – the most telling sign of an infestation. Branches sprouting low in the base of tree trunks, canopies thinning out and mature bark peeling off are also red flags. No one symptom is a tell-all sign of EAB.

Anyone who suspects EAB in their ash trees should contact the USDA Forest Service at 1-866-322-4512 or visit

Brenden West can be contacted at