Ash trees are safe from Emerald ash borer, for now

By Brandon Mattingly
Landmark News Service

Marion County and Washington County residents don’t have a new, unwelcome resident just yet - we don’t think - but it’s just a matter of time before that changes, according to Washington County Extension Agent Dennis Morgeson.
The Emerald ash borer, a beetle native to Asia, is believed to have been introduced to North America in Michigan in the 1990s, possibly in crates or pallets importing various products. They’ve been spreading across the country ever since.
“They probably entered Kentucky around four years ago around the Cincinnati and Louisville area,” Morgeson said. “These things usually start in the metropolitan areas because there are more people bringing things in. As of last year there were none in Washington County or Marion County. The closest county that has them to us right now is Shelby.”
While they may not have arrived yet, Morgeson said they’ll undoubtedly spread into Washington County and surrounding counties in the near future.
“It’s imminent, there’s no question,” he said. “They’re going to be here; it’s just a matter of time. They move very slowly on their own, maybe less than a couple of miles per year, but all it takes is somebody to cut some firewood this winter and bring it across the county line. If they don’t burn the wood that winter, the next year the borers are going to come out and we’ll have them here.”
The Emerald ash borer flies during the summer, laying its eggs on whatever ash trees it can find. When the borers hatch, they hold true to their name and bore into the tree, feeding from beneath the bark. Morgeson said it becomes a problem when the insect eats a complete circle around the tree over time, effectively killing the tree.
Washington County does have native ash tree borers, but they don’t cause the same problems the Emerald would present.
“Native borers only attack weakened trees or trees that are sick anyway, whereas the Emerald ash borer will attack any ash tree, whether it’s healthy or not,” he said.
Morgeson said the best indication that Emerald ash borers are present, is a D-shaped hole in the trunk with some sawdust around the hole or on the ground. As for what landowners with ash trees on their property can do to protect their trees, there is a product that can help on a year-to-year basis.
“The only thing you can do for a tree is get a product called Bayer Advanced: tree and shrub formulation,” Morgeson said. “Based on the diameter of the trunk, the label will tell you how much you need and you just mix it with water and pour it around the tree. That will protect it from six months to a year, from any insects for that matter.”
Residents may have noticed purple boxes in trees in various locations around the county, and Morgeson said those will help indicate when the insect arrives. So far, they’ve fortunately come up empty.
“The purple traps have a pheromone in them that attract the borers to it and they get stuck,” he said. “At the end of the season we can see if there are any ash borers. If there are none there, then we know that they’re not here yet.”
Now, we wait until the season ends to see if we’ve avoided the unwelcome guest for another year.