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Federal authorities confirmed this week that an invasive insect that has killed millions of ash trees in the United States, including in Wisconsin, has been found in another tree species in Ohio.

The U.S. Animal and Plant Health Inspection Service said in a bulletin issued late Wednesday that adult and larval specimens of emerald ash borers have been detected in four white fringetrees in the Dayton area.

The discovery is raising concerns that the emerald ash borer not only could infest ash varieties, as it has done in Wisconsin since at least 2008, but it could prey on other tree species.

"That's the more disturbing part," said Andrea Diss-Torrance, invasive forest insect coordinator at the state Department of Natural Resources. "This may be an indication of bad news to come."

The white fringetree is an ornamental tree. In Wisconsin, it is found primarily in the southern part of the state. It has been planted in limited quantities, but this is beginning to change as consumers discover them, according to Diss-Torrance.

Ash trees and fringetrees are members of the olive family. Diss-Torrance said experts will be watching to see whether emerald ash borers are attracted to lilac and privet trees, which are more common in Wisconsin and also are in the olive family.

The Animal and Plant Health Inspection Service said it will re-examine research to see whether other members of the olive family have been found to serve as hosts for the emerald ash borer. Lilac and privet in past studies so far have not been considered suitable hosts for the insect, APHIS said.

The agency also said it will try to determine whether the insect can complete an entire life cycle using the fringetree as a host.

Adult ash borers consume leaves of ash trees. In the larval stage, ash borers burrow beneath the bark, blocking the flow of nutrients in the tree, eventually killing it. They exit the interior of the trees, and in their insect form they look for a mate.

The insect is a native of Asia. Ash trees in North America have no natural defenses to fight the insect.

The Ohio discovery won't change Wisconsin's approach to the emerald ash borer, Diss-Torrance said.

State officials have been monitoring trees to find new outbreaks. In some cases, cities are removing healthy ash trees as a defense against infestations. Homeowners with valuable trees can treat ash varieties with insecticides.

While the discovery is important, Diss-Torrance said it is still too early to understand all of the ramifications. For example, the insects might not jump to another tree species in Wisconsin because ash trees are so prevalent.

Invasive insect

Emerald ash borers were first found in Michigan in 2002 and are believed to have hitchhiked in packing material from China.

They were detected in Wisconsin for the first time in Washington County in 2008. The biggest area of infestation is in southeastern Wisconsin. The insect is found across most of southern Wisconsin, as well as pockets of the far north.

Last week, an Ohio college professor announced he had evidence that emerald ash borers were attacking fringetrees. Federal authorities confirmed it this week.

Tom Tiddens, supervisor of plant health care at the Chicago Botanic Garden, has blogged on the emerald ash borer.

"Is the insect adapting? This is a scary thought," he wrote.

"What will happen when ash tree populations dwindle?" he said. "Will the EAB population die back, or just move to a secondary host (the meatloaf, as the prime rib is gone) and/or develop a completely new palate?"