Forester warns invasive beetle could be coming

Emerald ash borer sighted in communities near Shawano
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Shawano’s forester warned the Common Council that an invasive beetle could threaten trees in the area within the next 10 years.

Mike Kroenke told the council that there are a number of ash trees within the city limits, and they could be at risk if the borer finds its way here. Kroenke say there have already been beetles found in Green Bay and Waupaca, along with other Wisconsin communities.

The borer is an exotic species first discovered in southeast Michigan near Detroit in 2002. Adult beetles nibble on the foliage, but their larvae consumes the inner bark, which disrupts trees’ ability to access water and nutrients.

“It’s in 40 counties in Wisconsin, and there’s a quarantine against transporting emerald ash borers in any wood products,” Kroenke said. “The etymologist with the DNR says it’s going to hit Shawano within 10 years.”

Kroenke estimated that 7 percent of the trees on city property, including all of the parks and the cemetery, are ash. He said the city was “lucky” in comparison with other communities.

“If you look at Port Washington, and other counties in Wisconsin, they had a huge impact,” Kroenke said.

The city’s tree advisory committee is looking at developing a management plan to deal with the emerald ash borers.

“Other communities have those plans in place already,” Kroenke said. “We’ll probably talk with some of those people to develop our plan.”

Possible action could be preemptive removal of some ash trees, according to Kroenke, and replanting to keep them away from the beetles.

According to the Wisconsin Department of Agriculture, Trade and Consumer Protection, adult beetles emerge from beneath an ash tree’s bark between late May and mid-July and create a D-shaped hole as they exit the tree. The beetles live about 3-6 weeks, and when they find a mate, the female will lay 60-90 eggs.