Wednesday, May 13, 2009

Study aims to help ash borer prevention

By Bill Ford
Macomb Journal

Macomb, Ill. -

A Western Illinois University professor is teaming up with a WIU graduate to determine the best way to protect the University's ash trees from the emerald ash borer.

Thomas Green, an agriculture professor who specializes in urban forestry, and graduate Gary Watson, head of research at the Morton Arboretum in Lisle, are conducting a study on campus to determine the best way to distribute insecticide to ash trees in order to protect against the emerald ash borer, or EAB.

"We're looking at three different application rates," Green said. "We are going to try and determine which treatment will take up the most insecticide."

Green said one of the methods involved treating the mulch around the base of the trees, another is air spading, which blows soil away from the roots to expose them for treatment, while the third treats grass around the tree.

"Air spading loosens the soil and promotes root growth. We want to see if the air-spaded trees have more roots and, therefore, have more insecticide uptake," Green said. "We also don't know if the organic material in the mulch will inhibit insecticide uptake."

Green and Watson used an insecticide called Xytect, which Green said is recommended for use against the EAB.

"This chemical we are using has been used before, but we are looking at little different twist on it," Watson said.

The EAB is a shiny green beetle that bores into ash trees and renders them unable to transport nutrients. The beetle is believed to have made its way to the United States from Asia in packing materials. It was first reported in the Detroit area in 2002, but has since spread south as far as Missouri, leaving tens of millions of dead ash trees in its path.

The nearest report of EAB to here was in the Bloomington area, but Green said it is likely to come to Macomb eventually. Green said he is hoping the study spreads a little light on what are the most effective ways to protect trees before the beetle makes its way here.

"Having chemical in the tree is essential," Green said. "The tree may have emerald ash borer for two years and you won't know it because you don't see any die-back. It's hard to control them, so it is better to have chemical in the tree before the ash borer comes. Should the borer get here, we'll have trees that are protected."

Green said the WIU campus has approximately 160 ash trees, while Macomb City Forester Tim Howe said there are somewhere between 1,500 and 1,800 ash trees city-wide.

In six weeks, Green and Watson will take three samples from the tops of the trees - one in six weeks, a second in 12 weeks and a third in a year - to determine how much chemical the trees have maintained.

"We're hoping that it will pick up enough insecticide that when the emerald ash borer arrives, it will not colonize the tree," Green said.

Watson is doing an identical study in the Chicago area.

"It's another site with another possible set of conditions," Watson said. "Our seasons are a little bit different up there and we actually have ash borers up there very close to us."


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