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Pine False Webworm Uncommon In Wisconsin

Posted on by akabelowsky

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

Posted on by akabelowsky
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

Posted on by akabelowsky
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?

Posted on by janness

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

Posted on by janness

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

Posted on by akabelowsky
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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Forest Health Team Debuts Two New Fact Sheets

Posted on by akabelowsky
An image of the front page of a DNR fact sheet.

The front page of the Wisconsin DNR’s new Forest Health Fact Sheet on oak decline. / Graphic Credit: Wisconsin DNR

By Art Kabelowsky, DNR Outreach and Communications, Fitchburg
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

The Wisconsin Department of Natural Resources Forest Health team has published two new fact sheets, bringing the total count of its fact sheet offerings to 26.

The new fact sheets:

  • Fall Webworm: DNR Publication FR-622u discusses basic information on the biology of the insect (Hyphantria cunea), its life cycle, potential lookalike caterpillars and management options.
  • Oak Decline: DNR Publication FR-622v covers the tricky topic of oak decline, which is not caused by one distinct forest pest or problem but instead is the result of multiple factors — some predisposing, some inciting and some contributing — that work in combination to cause decline.

The fact sheets are designed in full color, with photos, and are meant to be printed out for reference or to carry into the field. They can also be viewed online. They can be printed on standard letter-sized paper. Most fact sheets are two pages, meant for two-sided printing; a few are four-page documents.

A complete directory of links to all DNR Forest Health fact sheets is available online.

Forest Health Staffers Plan Appearances

Posted on by akabelowsky
Two workers inspecting a tree's leaves.

Mike Hillstrom and Linda Williams of the Wisconsin Department of Natural Resources Forest Health team look over a tree during a walking tour put on by the Cambridge Tree Project on July 10, 2025. / Photo Credit: Wisconsin DNR

By Art Kabelowsky, DNR Outreach and Communications, Fitchburg
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

Mike Hillstrom, Invasive Forest Pest Coordinator for the Wisconsin DNR Forest Health Team, will make a presentation on forest health to the Heartland National Christmas Tree Organizations Convention, scheduled for Friday, Aug. 7, at Hann’s Christmas Farm, 848 Tipperary Road, Oregon, WI 53575.

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Oak Decline May Continue In 2026

Posted on by akabelowsky
A wide view of declining oak trees following spongy moth defoliation and drought.

Oak trees with thin canopies experiencing decline following spongy moth defoliation and drought in the prior few years. / Photo Credit: Wisconsin DNR

By River Mathieu, DNR Forest Health Specialist, Fitchburg
River.Mathieu@wisconsin.gov

Oak decline is a complicated forest health issue impacting oak forests in Wisconsin.

In the past few years, oak decline has been recorded in several regions of Wisconsin, primarily linked to spongy moth defoliation and drought conditions that occurred from 2022-2024.

As the summer months of 2026 continue to unfold, oak decline may continue in areas previously impacted by spongy moth and drought.

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Species Spotlight: Red Hailstone

Posted on by akabelowsky
A large creeping vine blankets neighboring trees and plants.

A red hailstone infestation in Dane County blankets surrounding vegetation and can be seen climbing into trees. / Photo Credit: Wisconsin DNR

By Carter Hellenbrand, DNR Invasive Plant Field Specialist, Fitchburg
Carter.Hellenbrand@wisconsin.gov

Note: This is the third installment in the Forest Health News “Invasives Spotlight” series, a series of articles released monthly during the growing season.

What is heart-shaped and hairy all over? Red hailstone!

Two hands holding tubers of the red hailstone plant.

Underground tubers of red hailstone. The tubers easily break off to create new plants. / Photo Credit: Wisconsin DNR

Also known as golden creeper or Manchu tubergourd (Thladiantha dubia), this invasive perennial vine can grow 18 feet in a single growing season and spreads through underground potato-like tubers that break off from the root system to create new populations.

 

 

 

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