Ash trees in danger from emerald foe
ROCKFORD — Sometime this summer, experts predict, someone in Boone or Winnebago County is going to find a green bug that attacks ash trees. When that happens, the Rock River Valley will join the war against the emerald ash borer, an uninvited import from Asia that has killed 20 million ash trees in Michigan and now threatens the species in Indiana, Ohio, Illinois and other states.
The metallic green beetle was first identified in North America in 2002. Last summer, it was found in northern Cook County and Kane County, and arborists say there’s no reason to believe it won’t keep coming our way.
“It’s probably here already, but we just don’t know it yet,” said John Richards of Tree Care Enterprises, Rockford. “It could be inside of trees feeding, and it hasn’t emerged yet.”
A deep evader
By the time someone spots the adult borer, it may be too late to save the tree in which it hatched. The insects lay eggs in summer, and the eggs hatch into larvae and tunnel inside the tree, where they feed on the inner bark and obstruct the tree’s ability to carry water and nutrients throughout. By the time new adults emerge in spring or a year later, the tree may already have been damaged beyond repair.
There’s no way Northern Illinois’ ash trees — which Richards estimates make up 6 percent to 8 percent of the tree population — are going to get through this unscathed. Many will be lost, said Richards, who has researched the problem and is preparing a presentation for local municipal and landscape officials.
The state of Illinois, which has about 130 million ash trees, will lose many of them, too, said Mark Cinnamon, a plant regulatory authority with the state Department of Agriculture whose office is in DeKalb.
On the bright side, said the two arborists, Illinois has been warned about the beetle, which Michigan was not, and can take advantage of what other states learned in the battle.
Pick-and-choose strategy
Millions of dollars were spent cutting every ash in milewide circles in Michigan and, “in every instance, the ash borer popped up again,” Cinnamon said.
That, and shortage of state and federal funds to fight the ash borer, rules out that technique. Instead, said Richards, municipalities and homeowners need to monitor ash trees and decide which ones are worth trying to save with injections.
Ash trees that are old, damaged or diseased are best taken down before they become homes for the borer. That approach, arborists hope, will minimize the loss, contain the spread of the borer and buy time until a solution is found. Scientists, who knew very little about the ash borer five years ago, are working on remedies, but they may be five or more years away.
The state will get a better idea of the threat here by surveying 34 Northern Illinois counties — all those north of Illinois 74 — this summer, Cinnamon said. Staff will check one ash tree every four square miles for the beetle and larvae damage.
Getting the word out
Local municipalities should make plans now to handle diseased ash trees and get the word out to homeowners and, especially, people in the green industry who must be involved in the battle, he added.
Private citizens can help by monitoring ash trees on their property and in their neighborhoods, and by following quarantines and suggestions regarding campfire wood.
If you are camping, it’s best to buy wood when you arrive at your site rather than risk bringing in larvae-infested wood, Cinnamon said. Some sites no longer allow campers to bring in wood.
Municipalities also need to monitor ash trees and prune any dead wood. They should decide how to handle lawn and yard waste once the beetle appears, Cinnamon said.
“Landscape waste is going to be a big issue,” he said. “When you pick it up, there is no way of knowing whether there is ash wood in the debris.”
If ash is included, the composting operation needs to include an expensive processing in a tub grinder, which ensures that no larvae survive. But few municipalities have the money to invest in that, which could cost $500,000 or more.
“It may be,” said Cinnamon, “that in some years during the flight season of the adult, which is May 1 to Sept. 1, we may not be able to pick up landscape debris. Or, during that time, it may have to be taken to a site where it can be processed.”
It doesn’t work, said Cinnamon, to ask homeowners just to put leaves and clippings in the landscape waste bags.
A possible solution
Developers must be involved, too, as they remove trees and brush to clear land for construction, Cinnamon said. They need to be educated about how to dispose of the landscape debris.
Cinnamon worked in Michigan in 2002 when the emerald ash borer was found there. He went back last fall.
“It was pretty shocking,” Cinnamon said. “Five years ago, there were communities that had pockets of ash trees. Some properties were dead and some nearby seemed in good shape.
“Now there are no ash in an area 120 miles in diameter. It spreads out a long way from Detroit.”
Will that be the case here? The Rock River Valley is on the alert, but so far has not made plans for tree removal or replacement, or precautions with landscape waste.
“There’s not a lot we can do. The emerald ash borer would be a nuisance but it wouldn’t devastate us,” said Dan Irwin of the Rockford Park District. “The main thing we’re doing is not planting any new ash trees.”
The district’s golf courses contain a variety of trees, Irwin said.
Bill Mohr of the Rockford Public Works Department said staffers are aware of the ash borer threat. To his knowledge, there hasn’t been discussion yet on such things as how to dispose of diseased trees.
Richards, who has spoken out on the city’s need to reforest itself with a variety of trees, said the ash borer price tag could be high. The cost of removing just one adult ash, and replacing it with another tree, could well approach $1,000, he said.
