Politics & Government

Ash Borer Possibly Here Already, Tosa's Forestry Chief Says

As new reports surround us, Ken Walbrant thinks it probable that invasive emerald ash borers have already infested some Wauwatosa trees.

For any Wauwatosa residents interested in helping save city-owned ash trees along their streets with an inexpensive treatment, the time is now.

With confirmed reports this summer of new infestations of emerald ash borer to the suburban southwest and, now, much nearer to the north, Wauwatosa is outflanked by the tree-killing bug.

So nearly surrounded are we, Ken Walbrant, Tosa's superintendent of parks and forestry, believes it is "certainly plausible" that the insect has already taken up residence in some trees in our city, somewhere.

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Walbrant – a self-described "tree guy" – has made it his business to know a lot about the Asian beetle that has destroyed millions of ash trees east of Wisconsin and was first discovered in the state in 2008 at Newburg in Ozaukee County.

In fact, it was Walbrant who recognized one of this year's new infestations, the first in Waukesha County, confirmed in Mukwonago by the Wisconsin Department of Agriculture, Trade and Consumer Protection on June 20.

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Now, another infestation has been discovered much closer to Wauwatosa.

The department announced Friday that trees in a neighborhood on the Milwaukee's northwest side near West Mill Road were confirmed to be infested.

Ash borer has now been confirmed in 12 Wisconsin counties: Brown, Crawford, Kenosha, La Crosse, Milwaukee, Ozaukee, Racine, Rock, Vernon, Walworth, Washington and Waukesha, according to WDATCP.

City treatment program offers low-cost prevention

All of which leads Walbrant to believe the bugs could already be among us.

"Since previous outbreaks in Newburg and Oak Creek have been determined to be more than two years old – five in the case of Newburg – at the time of discovery, it is certainly plausible that this critter is in Wauwatosa already," Walbrant said. "We just haven't found it yet."

"The newest discoveries in Waukesha County and the City of Milwaukee make the possibility even greater," he said.

Ashes can be saved for a small price, but only if treatments are applied before an infestation takes hold in the tree. It is effectively preventive, Walbrant said, but not therapeutic.

The city owns about 5,500 ash trees, Walbrant said. In some parts of Wauwatosa, they line street after street for block after block.

Walbrant said that so far, about 500 homeowners have been participating in a treatment program that costs around $20 and is good for two years of protection.

"Wauwatosa offers a treatment program for city trees to the adjacent property owner," Walbrant said, "whereby if the resident pays for the chemical, the city will apply it.

"This program is offered in the spring and fall. Every resident with an ash tree in the city right of way adjacent to their property is sent a post card in late winter offering this service.

"The cost averages $20 per tree and is good for two years, so once in the program the resident receives a notification once every two years reminding that the tree is due for treatment," Walbrant said.

The program is not available for privately owned trees. Walbrant suggested that anyone wanting to explore preventive treatment for their own yard ashes contact a certified arborist.

Anyone who wants to begin treatment this fall to protect their street ash need only call the Parks and Foresty office at 414-471-8420 to enroll.

Early infestations hard to spot

Experts with the DNR believe that most ash borer infestations start in the tops of trees, where the bark is thinner, and work their way down – one reason that positive identifications can take years after trees are first infected.

It's another reason for Walbrant to fear that the pest is here.

"It'll be one of the guys out pruning who will spot it," Walbrant said.

"I would stress that none have been identified in Wauwatosa," he said, "and we have nine arborists working in the field every day who have attended seminars on emerald ash borer and are familiar with the symptoms."

Walbrant has not only attended seminars, he has visited the site of every infestation found so far in Southeast Wisconsin to develop an eye for the disease.

A good eye for an outbreak

That experience served him well in June.

Walbrant, who lives in Walworth County under a residency waiver from the City of Wauwatosa, often shops at a supermarket in Mukwonago.

"I was coming out of the Pick 'n Save," he said, "and I noticed this big ash across the road, and I thought, 'Oh-oh, that doesn't look good.'"

Even from a distance, the tree had strong signs of ash borer infestation – branches dying from the top down, water sprouts growing in bunches along the trunk – but those same signs are not uncommon in ashes stressed for other reasons, such as drought and construction damage.

Walbrant took a closer look, though, and saw more. The tree had split, scaled bark, and then, the unmistakeable, up-close diagnostics: perfectly D-shaped holes, just one-eighth of an inch across, where the adult beetles bore their way out through the bark, and S-shaped tunneling under the bark made by feeding larvae.

Walbrant high-tailed it to Mukwonago Village Hall and reported his find. Mukwonago forester Dave Farina investigated and captured a beetle, which was positively identified as an emerald ash borer.

A much closer find, and just upstream

Much nearer is last week's discovery in Milwaukee, and it's unsettling not just because of proximity – it's less than 5 miles from the Wauwatosa border – but also because of the nature of its location.

Walbrant said that his observations lead him to believe that the natural spread of the insect has a tendency to follow wooded waterways, where ashes are common.

The Milwaukee find was in a neighborhood called, ominously, Menomonee River Hills, straddling the stream that winds through Wauwatosa from one end to the other.

Besides the 5,500 city ashes, there are thousands more on private property and many thousands more growing wild in county-owned parks and parkways, Walbrant said.


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