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DNR Participates In Beech Leaf Disease Detection Survey

Map of Wisconsin

A Wisconsin map showing results of a beech leaf disease survey that ran from 2023 to 2026. / Graphic Credit: Wisconsin DNR

By Art Kabelowsky, DNR Forest Health Communications, Fitchburg;
Arthur.Kabelowsky@wisconsin.gov; 608-335-0167

To date, there have been no confirmed discoveries of beech leaf disease (BLD) in Wisconsin landscape, and we are on the lookout for this disease.

The disease is primarily found on American beech (Fagus grandifolia) but can also be found on ornamental species like European, Oriental, and Chinese beech (F. sylvatica, F. orientalis, and F. engleriana). Although it has not yet been found in Wisconsin, recent discoveries of the disease in Michigan and other states highlight the continued importance of monitoring BLD’s expansion.

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Avoid Ash Trees When Scouting For Deer Stand Locations

A hunter climbs into a tree stand.

A hunter prepares to safely climb into a tree stand. Hunters are advised to stay away from ash trees when choosing a tree to use for their stand, due to the possibility of hidden damage to the tree due to emerald ash borer. / Photo Credit: Wisconsin DNR

By Wisconsin DNR

As deer hunters begin to scout for suitable tree stand locations, the Wisconsin Department of Natural Resources (DNR) warns hunters to avoid placing their deer stands in or near ash trees.

That’s because of the scourge of emerald ash borer (EAB), which has been confirmed present in all 72 Wisconsin counties. It has already left most ash trees in the southern half of Wisconsin dead or dying, along with many in Door County and the Mississippi River counties.

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Tips For Identifying Asian Longhorned Beetle And Lookalikes

Closeup of female Asian longhorned beetle.

A female Asian longhorned beetle has a shiny appearance, bright spots and black-and-white striped antennae. / Photo Credit: Bugwood.org

By Michael Hillstrom, DNR Invasive Forest Pest Coordinator
Michael.Hillstrom@wisconsin.gov

More than 300 species of longhorn beetles inhabit the Midwest. The invasive Asian longhorned beetle (ALB) is not yet one of them, with no Wisconsin populations reported.

But ALB’s potential for damage is great enough that state agencies are asking members of the public to be on the lookout for the insect — and to avoid being confused by a relative lookalike.

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Species Spotlight: Japanese Stilt Grass

Wide view of a patch of Japanese stilt grass.

A dense patch of Japanese stilt grass growing within a forest. / Photo Credit: Wisconsin DNR

By Carter Hellenbrand, Invasive Plant Field Specialist, Fitchburg;
Carter.Hellenbrand@Wisconsin.gov

Note: This is the fourth installment in the Forest Health News “Invasives Spotlight” series, a monthly series of Forest Health News articles.

What has stilts, is green in the summer and reddish-purple in the fall? Japanese stilt grass!

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Pine False Webworm Uncommon In Wisconsin

Messy webbing filled with frass (droppings) and pieces of needles are signs of pine false webworm feeding on this young white pine. The arrow points to a pine false webworm larvae. / Photo Credit: Wisconsin DNR

By Linda Williams, Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov, 920-360-0665

Pine false webworm (Acantholyda erythrocephala) is not a very common insect in Wisconsin, though it is present. They prefer to feed on white pine in Wisconsin, though reference materials say they will also feed on red pine, jack pine and Scotch pine.

Damage was reported as “minor” in the central part of the state from 1953 to 1961. Later, in 1995, 1997, 2002, 2004 and 2006, it was once again observed as a minor pest feeding on red or white pine in the central part of the state, particularly Portage, Waupaca and Waushara counties. In 2024 and again this year, a few scattered young white pine were observed being significantly defoliated in Oneida and Vilas counties.

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Japanese Beetle Populations Still Building In The North

Beetles feeding on a basswood leaf.

Japanese beetles defoliating a basswood leaf. / Photo Credit: Wisconsin DNR

By Linda Williams, Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov,  920-360-0665

The Japanese beetle (Popillia japonica) is an invasive insect that feeds on many plant species. The adult beetles “skeletonize” leaves by eating the material between the veins.

Adult Japanese beetles feed on the flowers and leaves of more than 300 plant species, including trees, shrubs and herbaceous plants. Forest trees can be defoliated, with open-grown or edge trees suffering the highest defoliation rates.

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Forest Health Staffers Plan Public Appearances

Two DNR workers discuss tree issues in the forest.

Alex Hornung, Wisconsin DNR Forest Health specialist for Central Wisconsin, discusses the tree disease phomopsis with Chief Forester Heather Berklund during a site visit near Minocqua in July 2026. / Photo Credit: Wisconsin DNR

By Art Kabelowsky, DNR Forest Health Communications, Fitchburg;
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

Alex Hornung, the Wisconsin Department of Natural Resources Forest Health Specialist for Central Wisconsin, will discuss oak wilt biology at a workshop this month.

Hornung will take part in a Wisconsin Forestry Center/Wisconsin Natural Resources Foundation workshop on oak wilt biology and management, focused on information for landowners and the public. The discussion will take place from 1 to 3:30 p.m. Tuesday, Aug. 18, at Schmeeckle Reserve, 2419 N. Point Drive, Stevens Point. She will be joined by Dr. Holly Petrillo, Professor of Forestry at the University of Wisconsin-Stevens Point.

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How Big Will My Tree Get?

By Elton Rogers, DNR Urban Forestry Coordinator
Elton.Rogers@wisconsin.gov or 414-294-8675

This is one of my least favorite questions to get as an urban forester/arborist; it’s right up there with “how old is my tree?” The reason I despise this question is not because it is a bad question, but rather it is a complex one. A question that often requires much more discussion than the person who asked it is looking for… Continue reading “How Big Will My Tree Get?”

Tree Species In An Uncertain Future Climate

By Dan Buckler, DNR Urban Forest Assessment Specialist
Daniel.Buckler@wisconsin.gov or 608-445-4578

One of the many challenges for urban foresters in navigating climate change is the fact that while temperatures are elevated across every season, it can still get pretty cold in Wisconsin, even along Lake Michigan. Nonetheless, hardiness zones are shifting, and there is plentiful experimentation underway by Wisconsinites to identify which tree species are appropriate for their location throughout the 21st century.

The Northern Institute of Applied Climate Science produced species vulnerability lists for six locations in Wisconsin, projecting what species are likely at increased risk (i.e. more vulnerable) under different climate change scenarios. Those are great resources that use the same background methodology as a species vulnerability analysis done for the Milwaukee metropolitan area. Continue reading “Tree Species In An Uncertain Future Climate”

First Populations Of Invasive Pale Swallow-wort Confirmed In Wisconsin

Closeup of pale swallow-wort flower cluster.

Pale swallow-wort flowers along the stem at the leaf axils. / Photo Credit: Chris Evans, University of Illinois, Bugwood.org

By Mackenzie Manicki, DNR Natural Resources Research Scientist

The Wisconsin Department of Natural Resources has confirmed that the state’s first populations of the invasive vine pale swallow-wort (Vincetoxicum rossicum) have been found.

The populations were first detected in Oconto and Shawano counties, within the outskirts of Krakow along the shared county line.

These are the first known populations in the state, making rapid response efforts critical in preventing the establishment of this species in Wisconsin.

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