New Berlin — A scourage that foresters deem to be as devastating as Dutch elm disease has now reached into the city.
On Monday, New Berlin officials announced that the emerald ash borer has been confirmed in four widely scattered sites locally — in a tree in the extreme northwest corner of the city; and in traps at Calhoun Park, 5400 S. Calhound Road; at 124th Street and Howard Avenue; and at the city recycling center near City Hall, 3805 S. Casper Drive.
New Berlin is the fourth Waukesha County community to confirm the presence of the ash-tree-killing beetle, whose larvae feed on the inner bark of host trees and resrict its ability's to transmit nutrients. It was first confirmed in Mukwonago last year, then in Oconomowoc, then New Berlin and the city of Waukesha last week.
"I think it was inevitable," said Mayor Dave Ament.
"It's a ticking time bomb and the fuse is getting shorter," said New Berlin forester Paul Fliss.
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And it's ticking for homeowners as well as the city, Fliss said.
The borer has probably already been in the city for three or four years undetected, he said. That puts it closer to the tipping point of nine years when the borer starts to take down 20 percent of ash trees every year until they are either gone or treated, Fliss explained.
Because treatments are expensive, Fliss advises home and business owners to decide which ash trees they really want to keep and start treating them now. By the time the D-shaped holes the borer leaves when it exits the trunk, it's usually too late to save the tree. The borer starts at the top and works its way down, he said.
Those that have lost half their leaves cannot be saved, according to emerald ash borer research.
The New Berlin city website now has links to information that will help homeowners decide how to deal with the onslaught. It also has answers to the most-asked questions about emerald ash borer. Or people can call the city's Parks, Recreation and Forestry Department at (262) 797-2443 or contact the Wisconsin Department of Natural Resources EAB Hotline at (800) 462-2803.
Types of treatment
Treatments are of two kinds, but only a professional injecting trunks with emanectin benzoate has proven reliably effective, according to researchers from five universities who have published a multistate paper accessible online at emeraldashborer.info.
"In several intensive studies conducted by (Michigan State University) and (Ohio State University) researchers, a single injection of emamectin benzoate in mid-May or early June provided excellent control of EAB for at least two years, even under high pest pressure," the researchers wrote.
Other treatments have provided widely varied excellent-to-poor control. Researchers are still studying why the same preparation works sometimes and not others.
For trees of 45 inches around the trunk or less, homeowners can generally get good results by mixing water with preparations containing imidacloprid, available at local garden centers for about $22. This is most effective when applied between April 1 and May 15, according to the Purdue University decision guide. The treatments are good for a year.
But for larger trees, the researchers say homeowners should consider professional treatments.
Trunk injections with emanectin benzoate, the only known substance providing protection for two years, could run in the neighborhood of $150 and $195 for trees 45 inches around or with breast height diameters (which is how arborists look at trees) of 15 inches. A tree that's 75 inches around at chest height could cost $250 or $360 to treat with emanectin benzoate.
Arborists also can inject the soil with imidacloprid in amounts homeowners are not allowed to use. Such injections are 80 percent effective, said David Scharfenberger, president and an owner of Wachtel Tree Science of Merton, which serves New Berlin. Soil injections are $122 for a tree that's 45 inches around, but have to be repeated annually, so it's more expensive than the trunk injections.
Costs of treating should be measured against the cost of cutting a tree down, experts suggest. A tree can cost anywhere from $300 to $2,000 to cut down.
AT A GLANCE
The websites the city recommends for getting information about the emerald ash borer are:
Or people can call the New berlin Parks, Recreation and Forestry Department at (262) 797-2443 or contact the Wisconsin Department of Natural Resources EAB Hotline at 1-800-462-2803.
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