Ash borer remains a threat to Ohio trees

Those with ash trees on their property beware: the emerald ash borer is still killing and presenting a danger to ash trees across the entire state of Ohio.

Ohio Department of Natural Resources (ODNR) Forest Health Forester Tom Macy said the emerald ash borer has been seen in the largest volumes in central Ohio.

“It’s definitely still a large issue throughout the state,” Macy said. “We’re still seeing a lot of mortality (of ash trees). The majority (of the ash borer) is in the central (region) of the state, around Columbus and Dayton.”

Macy said that while there were no confirmed cases in Washington County or any surrounding counties, the borer could still be there. He added that confirmed cases meant an adult or larvae had to be taken out of the tree.

“It’s suspected that it’s probably state-wide at this point, but it’s not confirmed yet,” he said.

Each year, a number of ash trees are cut down in and around Marietta, said Councilman Harley Noland, who also serves on the Marietta Tree Commission.

“We try to get them down before they fall down and damage people and property,” he said.

Noland said the tree commission has two funds, one to cut down trees and one to plant new ones. He added the new trees are always of a different and varying species.

“(Commission member) Marilyn (Ortt) and the tree commission stood up for a diverse tree population in the city,” he said, adding that the variety of new trees planted is “really wide.”

Noland said the money in the funds is gathered once in a while from grants, but mostly from donations and city income tax.

Ortt said taking down an ash tree can be expensive, easily topping $900. She added that the replacement trees are determined by their cost as well as the site.

“We look at the site and say this is a good site for A, B or C,” she said. “Until we see the quote each year, we don’t know (what we’ll plant); we might settle for D. Diversity is the important thing. If you don’t have diversity, (the trees) are not resilient against insects and disease.”

Macy said there are ways to help prevent the spread of the ash borer, the most important of which is not transporting wood from one area to another.

“We still recommend that folks not move wood if they can; avoid moving and burning fire wood,” he said. “If you need it, buy it locally.

Macy said another way to stop the spread is to treat trees already infected by the ash borer.

“Option two is to treat individual trees with insecticide to protect the tree,” he said. “The insects won’t reproduce.”

Ortt said the treatment for trees is expensive, but so is cutting them down.

“I think we could consider treatment,” she said.

She said if the decision was made to treat any ash trees, it would be because they are in very good health.

Macy said studies are being done by several federal agencies for bio-control with a wasp species that is a predator of the ash borer. He also said studies are being done to find naturally resistant ash trees that have an immunity to the borer and start breeding them.

“The outlook is pretty grim,” he said. “There’s not much we can do right now except treat individual trees.”

Macy said the best way to prepare is to talk to a local urban forester who can help develop a management plan.

“They will do inventory of city and community trees and how best to prepare for (the ash borer),” he said. “The best thing is to develop a management plan.”