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June 26, 2012 | 04:25 PMTo the rescue.
The Lake Geneva City Council voted unanimously on Monday to set aside $10,000 to fight the emerald ash borer threat to city ash trees.
The city will spend its own money to start the ash borer abatement.
Alderman Bill Mott, who chairs the public works committee, said between the alternatives of cutting down all 300 or so of the city-owned ash trees, and trying to save some of the ash trees from the insect, the committee came down in favor of saving the trees.
Public Works Director Dan Winkler told the council that the abatement program will start early this fall, at the recommendation of City Arborist John Foster.
The insects are laying their eggs now, Winkler said. Applying the treatment this fall will allow the chemical to travel through the trees and kill the borers before they can do much damage.
The program applies only to city-owned trees.
Private ash tree owners will have to find their own arborists to protect their trees. Foster told the tree board last week that he can give advice, but he's not licensed nor equipped to protect privately-owned trees.
Ash trees do not make up a majority of city trees. Winkler said the city stopped planting ash trees when news came out in 2002 that the emerald ash borer had been discovered in Detroit.
It's taken awhile for the pest to reach this far. After burning through Michigan, Indiana and Illinois, the ash borer invasion has slowed, but it's still expanding.
So far, infested trees in Wisconsin have been identified in Brown, Crawford, Kenosha, La Crosse, Milwaukee, Ozaukee, Racine, Vernon, Washington, and Waukesha counties, as well as Walworth.
The first 10 counties are under quarantine. Walworth County's quarantine is pending.
Almost two weeks ago during routine pruning, City Arborist John Foster spotted an ash tree with the telltale D-shaped exit holes of emerald-ash-borer infestation.
Foster said that the insects had already taken flight to find other trees.
Foster's discovery came shortly after the discovery of the first ash borer infested tree in Walworth County, which was growing south of the village of Walworth.
Since then, in discussions with the city council's public works committee and the city's tree board, Foster and Public Works Director Dan Winkler have developed a plan to use a chemical treatment called Treeage (pronounced the same as "triage.")
The active chemical in Treeage is a poison that kills the borer at any stage of life, from larva to adult. It's considered to be 95 percent effective and stays in the tree.
The chemical is injected, and the injection spot is protected with a rubber plug.
Foster has selected about 200 trees, based on trunk diameter, that he believes the city can save the trees with an application process that starts in early fall.
Foster told the tree board last week that experts recommend Treeage as a treatment. It's safer than a spray or soil treatment because the poison stays inside the tree, he said.
The chemical is not cheap. According to information from the tree board, it costs about $495 a liter.
Individually, trees receive an injection of 50 milliliters, for a cost of $25 per tree per application. Add in equipment and labor and the cost per tree comes to $60, Winkler has said.
By comparison, removing a 25-to-30 inch diameter tree costs about $2,000, not including replacement tree, Winkler told the tree board last week.
Application is once every two years, although it might be once every three years for some trees.
Winkler said the city could apply for a state grant, but it would delay application until spring. The grant would also cover about half the cost of the chemical alone, which means the city would receive about $3,000 in grant money for the $10,000 treatment package.
The city doesn't have many ash in its parks, Winkler said. Most are in the city's rights of ways.
All told, the city has 300 ash trees out of an urban forest of more than 4,000. Anywhere from half to 60 percent of city trees are maples, which are not affected by the borer.
The DNR is also offering the city the services of a team of tree specialists who will survey the city's ash tree population for free, Winkler said. The tree board and Winkler agreed that the DNR should be invited to do the survey.
According to Winkler and Foster, ash trees larger than 28 inches in diameter and smaller than 6 inches will probably be removed when found infested, and then replaced.
Some Tax Increment Finance district money may be available for the removal and replacement of infested ash in the downtown area, City Administrator Dennis Jordan has said.
The emerald ash borer is a native of Asia. In its habitat, the borer usually doesn't kill trees because the ash trees in that part of the world are resistant to the beetle.
It's believed that the ash borers arrived in this country in the late 1990s in a consignment of crates from China made with infested wood.
The ash trees here have no natural defenses against the emerald ash borer and the ash borer has no natural enemies to keep its numbers under control.
The state is now experimenting with an imported wasp that preys on emerald ash borer. The wasps are small and do not sting humans.
So far, it appears that the emerald ash borer is here to stay.
However, Foster has said that history holds out some hope.
A half century ago, urban elm trees were decimated when Dutch elm disease cut through the nation's forests.
Dutch elm disease is still around, but now so are Dutch elm disease resistant elm trees, Winkler said.
"Elms are coming back that are resistant to Dutch elm disease," Foster said.