Purdue News

January 27, 2004

Emerald ash borer nears northern Indiana borders

WEST LAFAYETTE, Ind. - A Purdue University entomologist says there are things Indiana residents can do to slow the spread of an invasive insect pest that threatens ash trees and is closing in on Indiana.

emerald ash borer
Download photo - caption below

Jodie Ellis, the exotic insects education coordinator at Purdue, said the emerald ash borer is nearing Indiana, and Hoosiers need to readjust their thinking now to help slow the insect's spread. To that end, she suggests that people be very careful when moving nursery stock and avoid moving firewood.

"The infestations that occurred outside of the core area in Michigan and those found in Ohio, Maryland and Virginia happened because humans moved infested ash products," Ellis said. "More than likely they occurred when firewood or nursery stock was moved."

The metallic, coppery-green beetle has already caused the demise of more than 6 million ash trees in Michigan since it was found in July 2002, and that number continues to grow. Of special concern to Hoosiers are the infestations found just two miles from the Indiana border near Fort Wayne and one found this month in St. Joseph, Mich. This brings the beetle much closer to northwestern Indiana and Chicago.

Bill Hoover, a Purdue Extension forestry specialist, said there are approximately 150 million ash trees in Indiana.

Ellis said residents should keep an eye out for signs of the pest. Hoosiers who see evidence of emerald ash borers should contact Ellis at (765) 494-0822 or the Indiana Department of Natural Resources Invasive Species Hotline at (866) 663-9684.

It's difficult to diagnose emerald ash borer damage because of the prevalence of other ash-boring pests in Indiana. Ellis conducted a survey last year in West Lafayette, Ind., that yielded at least five native species of ash pests. One of the main ways to distinguish emerald ash borers from native species is the characteristic D-shaped exit holes in the main trunk and the rate at which it kills trees. Other symptoms include vertical splits in the bark and increased woodpecker activity.

Ellis said Indiana residents have an advantage in fighting the pest because they know what's coming.

"We need to start thinking about what will happen when emerald ash borer is found here," she said.

In Ohio, when emerald ash borer is found, all ash trees within a one-half mile radius are cut down and chipped. A similar regulatory action may be necessary in Indiana if the beetle's presence is confirmed.

Because of that, Ellis said, "At this time we don't believe it's prudent to apply preventative treatments on ash trees. You can try to keep the beetle out of your tree, but you may not be able to keep the chainsaw out of it if you're near an infestation."

Instead, she said, residents should concentrate on keeping their trees healthy with adequate water – about one inch of water per week.

Homeowners who are planning on landscaping also should take the insect into account.

"It's probably not a good idea to plant ash trees for the time being." she said.

Ellis said, however, that strategy could change as better control methods and natural predators are discovered. The beetle is widespread in China, where it originated, but Ellis said ash trees there have some natural resistance and natural enemies.

"We're moving as quickly as possible, but there's very little information available about this pest."

Additional information and photos of the emerald ash borer are available at Purdue's emerald ash borer Web site.

Writer: Kay Hagen (765) 494-6682, kjh@purdue.edu

Sources: Jodie Ellis, (765) 494-0822, ellisj@purdue.edu

Bill Hover, (765) 494-3580, whoover@purdue.edu

Ag Communications: (765) 494-2722; Beth Forbes, bforbes@aes.purdue.edu
Agriculture News Page

PHOTO CAPTION:
The emerald ash borer is responsible for millions of dollars of damage to ash trees in Michigan. The adult borer is a metallic, coppery-green color and one-third to one-half inch long. (File photo/David Cappaert of Michigan State University and courtesy of www.forestryimages.org)