Tree-killing beetle discovered in southern Illinois

By Muriel Berry

The Emerald Ash borer, an invasive species of beetle responsible for the deaths of more than 250 million ash trees throughout the U.S., has been discovered in Perry and Williamson counties.

The beetle is native to Asia and eastern Russia, but was first found destructive in the U.S. in 2002 in Detroit. The Illinois Department of Agriculture detected the insect in Perry and Williamson counties thriving in local trees by setting traps for the bug.

While the borer poses no threat to humans, it could have a devastating effect on agriculture in southern Illinois, and even at SIU.

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Daniel Nickrent, professor of plant molecular systematics and evolution, said there is a significant ash tree population on campus.

“There are at least four species of native ash,” he said. “In terms of ash tree, SIU hired a tree survey of campus a few years ago, [the survey] recorded [more than] 200 ash trees.”

There is a possibility borers could end up on campus because ash trees are a natural habitat for it.

Benjamin Snyder, district forester at the Illinois Department of Natural Resources, said a borer population in rural woods could lead to a decrease in wood product sales, aesthetics and diversity. The beetle can also cause problems for urban communities where ash trees are commonly used for décor or shade.

“The United States Forest Service estimated that the impact on the urban landscape is 0.5-2 percent loss of total leaf area at a cost of $20 billion to $60 billion,” he said. “Costs in urban areas are from removal and replacement of dead and dying trees, as well as planning.”

William Eshbaugh, professor emeritus of botany, said there is a chemical called “Tree-age” that can be used to treat the infested trees and kill the insect. Although this insecticide costs around $700 per liter, it enables the ash trees to live an additional two years before another treatment is needed.

Nickrent said other colleges such as Miami University in Oxford, Ohio had already seen the negative effects of the borer.

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“Many mature ash trees are being cut down because they have been completely killed by the beetle,” he said. “Unfortunately, I think our campus will be experiencing the same thing as MU as the EAB moves south.”

Muriel Berry can be contacted at [email protected]or on Twitter @Muriel_Berry_DE or at 536-3311.

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