Arboretum: Time is now to fight ash borer
To no one’s surprise, the pesky emerald ash borer is back.
Communities throughout DuPage County have reported a new round of infestations, including Wheaton officials who say the tiny metallic green insect already has been found in twice the number of ash trees as last year.
But officials at the Morton Arboretum in Lisle say homeowners can fight back against the critters.
Plant clinic assistant Donna Danielson said homeowners should treat ash trees with Imidacloprid, a commercially available insecticide that has proved effective against the insect, which first appeared in Illinois in 2006.
“Any ash tree not chemically protected in some way will get it and die,” Danielson said.
The ideal time for treatment, which should be done annually, is April and May, Danielson said. The water-chemical mix soaks the soil at the base of the trees and sends the chemicals, which are safe for trees but toxic to the insect, up the trunk of the tree.
Danielson said the insecticide is not foolproof but it remains the best option, short of hiring a professional arborist.
After five years of dealing with the problem, officials and scientists have pinpointed several telltale signs of infestation, including dead branches at the top of trees, D-shaped exit holes on tree bark and woodpecker activity.
Lisle village arborist Duane Henry said that was how he noticed an infestation on several trees along Benedictine Parkway.
“The trouble is, it is so hard to discover until the population gets so high, by that point, it’s too late for the tree,” he said.
Tarp traps set by the Illinois Department of Agriculture found Lisle’s first infestation last year, two years after they had been identifying and removing ash trees deemed in poor condition.
The approach is similar to the one taken by Wheaton officials, who in 2008 surveyed the city’s 6,000-plus ash trees and removed more than 700 that were in “fair” or “poor” condition. The move was made after the beetle was discovered in neighboring Glendale Heights and Carol Stream.
“It’s a little more prevalent this year,” said forestry superintendent Kevin Maloney, who noted that 21 cases have been confirmed this year, up from 10 last year. “I’m sure there will be more but, at this point, we’re just removing the confirmed cases.”
“It’s an ongoing hassle,” Wheaton Mayor Mike Gresk said. “It’s a question of just being vigilant.”
The emerald ash borer, labeled “The Green Menace” by the U.S. Department of Agriculture, first arrived in Illinois in 2006 in Lily Lake. Since then, it has spread and last year arrived in Wheaton for the first time. As of this month, more than 100 communities in Illinois have discovered it in 2011.
The characteristic D-shaped holes in infected trees come from emerging adults, which lay dormant during the winter and develop from wormlike larva that rob the trees of nutrients for growth.
Stop The Green Menace
Ÿ Dont move firewood. Buy local, burn local.
Ÿ Visually inspect trees. Symptoms include D-shaped exit holes on tree bark and wormlike grooves in trees.
Ÿ Spread the word. Talk to neighbors and friends about what to look for.
Ÿ Know state and federal regulations. Understand rules regarding the bug in your state and any you plan to visit.
Ÿ Ask questions. If you receive ash stock or firewood, find out where it originates.
Source: U.S. Department of Agriculture.