Emerald Ash Borer Has Ohioans on Alert

Ohio researchers remain vigilant of the Emerald Ash borer as they wait to learn how far the nonnative insect has spread.

Dave Shetlar, Ph.D., of the OSU Department of Entomology, updated green industry professionals on the status of the borer during his presentation on insects in ornamentals at the Ohio State University and Ohio Turfgrass Foundation’s Turfgrass Research Field Day Aug. 16 in Columbus. At the event, OSU Turfgrass faculty members and researchers discussed the latest findings on turf disease and insect control for more than 300 landscape contractors and golf course maintenance workers.

The destructive insect, which migrated to the U.S. from Asia, landed in Michigan at least 10 years ago and has been spreading to other states, including Ohio.

The borer feeds on the cambium area of the tree. Because the insect is from Asia, the tree has no defense system and dies when attacked.

Awareness has been raised about the borer, but some are unknowingly transporting it to new areas, Shetlar says.

“It used to be spread by nursery stock, but that’s being stopped,” he says. “Now it’s coming from cheap firewood.”

Shetlar describes the warning signs as trees with large areas of bark sheared off. The trees can be treated to decrease the borer count, but Shetlar warns that once the tree is infected, it cannot be saved. Treating it only prolongs the inevitable.

“Even the best treatment is 80 to 90 percent effective,” he says.

One advantage to treating the tree and prolonging the life is that this can allow for the trees to be replaced gradually instead of all in one year, Shetlar says. Municipalities are opting to do this, cutting down a few trees each year and replacing them as they go.

As far as a treatment method, some studies conclude the insecticide Merit is effective in prolonging the tree’s life. Other studies, Shetlar points out, show that Merit kills the tree.

An Emerald Ash Borer Task Force has formed to help determine what action should be taken to combat the destructive pest. Shetlar says data on the insects’ spread won’t be available until November or December, because that is the best time to get samples from trees. There already have been EAB detected in Toledo and outlying areas, especially at rest stops and state park grounds. Shetlar predicts five or six more locations in the Ohio will be found to be infested with the EAB.

The state has used up its funds to fight the insect and is waiting for the data to learn the extent of the infestation before discussing a course of action.
 
Other presentations for lawn care professionals at the field day included findings of weed and grub control research and irrigation conservation studies.