Treat or remove? Suburbs struggle with ash borer
Second of two parts
Sam Moser fights the emerald ash borer to save the lovely tree canopy on his street.
Jim Bell, meanwhile, sees the green of dollars as well as leaves. For him, treating infested trees is part of a larger plan to save the Elgin ash trees he can, while preventing a budget disaster in his city.
The viewpoints of an Arlington Heights homeowner who worries about hundreds of trees in his neighborhood and the Elgin parks superintendent responsible for 7,000 public ash trees are different. But they both believe that ash trees can and should be treated, and insecticides are critical in the battle against this tiny bug.
As late as 2006, when the first Illinois emerald ash borers were confirmed in Kane County, officials thought the infestation could be contained by quickly cutting down infected trees.
They soon learned that did not work — mainly because the pest takes three or four years to cause noticeable damage and was already widespread before its detection.
Scientists now insist some trees can be saved if treated.
But treating trees can be a financial gamble, especially if they are already infested, and Scott Schirmer, emerald ash borer program manager for the Illinois Department of Agriculture, doesn't believe any suburban ash trees have escaped the borer.
While many sources say a tree can be treated and saved if at least 60 percent of the canopy — leaves and branches — is alive, there is not universal agreement. Wayne White, a Michigan arborist whose Emerald Tree Care has followed the pest to Illinois, says he will not guarantee a tree can be saved if the canopy shows any damage.
And over the years the cost of professionally treating a tree eventually adds up to the price of removing and replacing it, he said.
“You don't want to waste money treating an ugly tree,” said White. “The tree is not going to look any better than it does today.”
Dru Sabatello, Arlington Heights village forester, is more optimistic. He first worried that infected trees would be too damaged to get much use from insecticide, which the tree must carry up its vessels to the branches and then the leaves.
The borers eat those vessels and interrupt the flow of water and insecticide to the top.
However, “I'm starting to become more confident. The trees are healthier looking than I thought going into this season,” said Sabatello. “(TREE-Age) is lethal to the larvae, there's no mistaking that. If the tree can take it up, it's effective.”
Bell, meanwhile, is part of a national coalition of professors, local government officials and representatives of tree care and pesticide companies that believes insecticides belong in any ash management program.
Bell's crews are treating 2,000 ash trees in Elgin, have removed 1,400 and plan to take down another 3,500, at a rate of 500 a year.
Ash trees — at least 14 percent of the city's parkway trees — were assessed according to their location and condition, and officials decided to treat only trees with diameters between 8 and 20 inches.
Smaller ash trees are being cut down and replaced with another variety.
As for larger trees, early tests indicate the treatment might not work on them, but more research is under way.
“That's 2,000 trees we don't have to remove,” Bell said. “We focus on fairly high liability trees for removal and hopefully replanting. Treating trees buys you time.”
Treatment of public trees in Elgin costs $24 a tree per year because it is done by city crews.
That compares with $800-$1,200 to remove and replace a tree.
And buying time, even for trees that won't make it, is useful because dead ash trees are very brittle and may fall over on people, cars or homes within a year of expiring.
Treat for 6-8 years
Sam Moser was the first in Arlington Heights to organize his neighbors in the Heritage Park area to fight the ash borer in their parkway trees. The group selected TREE-Age, and were given a group discount.
“Parkway trees have more to do with the look of the neighborhood — beautiful, high-canopy tree-lined streets,” he said. “People commented to me that was part of their decision to buy a house on our street — the character and large trees.”
Homeowners who want to treat their parkway or private trees have a variety of options, some relatively low-cost.
In northeastern Illinois, the main treatments available are Imidacloprid, which is now available under several brand names; Emamectin Benzoate, available only as TREE-Age; and Dinotefuran, branded as Safari or Transtect. There is considerable faith out there in all of them.
Imidacloprid can be put on the soil at the base of the tree, injected into the soil or injected into the tree; TREE-Age is only injected in the tree, and Safari can be sprayed on the bark, injected in the soil or spread around the base of the tree.
Imidacloprid and Safari can be purchased by homeowners — generally for pouring or sprinkling around the base of the tree. Only licensed applicators can use TREE-Age.
All treatments have caveats and directions about methods, doses and precautions.
Deborah McCullough, professor of entomology and forestry at Michigan State University, is a member of the Coalition for Urban Ash Tree Conservation.
She also is co-author of a study about the effectiveness of insecticides against emerald ash borer.
“TREE-Age is the only one you don't have to apply every year,” she said. “We're getting two and maybe three years from it. The level of control is higher than anything else we've seen. Some of the other products work if you apply them every year.
“You don't necessarily have to kill every single ash borer to get the tree through the big invasion.”
The general belief is that treatment must be aggressive for six to eight years until the infestation passes.
When the borers start to die off or move on due to a dearth of ash trees, the surviving trees may be able to fight off the few remaining insects on their own or with occasional treatment, said Fredric Miller, professor of horticulture at Joliet Community College and research associate at Morton Arboretum in Lisle. Research shows that natural parasites might eventually help, too.
Miller, who has been studying emerald ash borer treatments in the suburbs since 2007 and is part of the coalition, attributes skepticism about treatment to early studies of insecticides that produced inconsistent results.
The first Imidacloprid mixtures were not strong enough for a bad infestation in trees 12 to 15 inches in diameter, he said. Since late last year the active ingredient has been doubled, which seems to work better.
“EAB kills untreated trees,” Miller said. “And the insect works on its schedule. Communities will find if they don't decide to treat some trees they will be overwhelmed.
“It will cost a huge amount of money to take down the trees, and it will be a logistical nightmare to find enough crews to come in and help.”
The different treatments all have their advocates.
White, who has contracts with West Chicago and Roselle, says he has been saving ash trees with Imidacloprid in devastated areas of Michigan and Indiana for 10 years. He both injects a tree and puts the insecticide around its base.
Joe Chamberlin, regional field development manager for Valent Professional Products, which sells Safari, said he would use TREE-Age on a tree that has lost 20-40 percent of its canopy.
He said Safari and Imidacloprid, which chemically are similar, work best on trees with up to 20 percent damage.
The trees must be able to take up water for the treatment to work. White prefers treating from mid-April to mid-May but says fall is the next best time.
Chamberlin said Safari can be used after a tree has leafed out in the spring, which gives owners a chance to evaluate its health before paying for treatment.
Jake Balmes, a certified arborist who is now the Gurnee street supervisor, said his village held off treating ash trees during the worst of the drought, and jumped into action with the first drenching rain a few weeks ago.
“We ran out and treated ... another 1,400 (with TREE-Age), over 100 trees a day,” he said. “They were so starved for moisture ... I have never experienced uptake like that. It was almost instantaneous.
“It's pretty clear we are getting really good results,” Balmes added. “I wasn't sure this spring (but) later in the summer you can tell the difference. Trees we treated are holding steady or showing more growth, those we didn't are clearly declining.
“These are right next to each other, it's like night and day.”
Ÿ Staff writers Melissa Silverberg and Eric Peterson contributed to this report.
Emerald ash borer series
<b>Sunday</b>: Landscape forever changed in suburbs
<b>Today</b>: Government, residents decide between treating and cutting down
<b>Tuesday</b>: Can a future disaster be averted?