Woodland owners

Look For Spongy Moth Egg Masses And Take Action

Posted on by akabelowsky
Closeup of a person scraping spongy moth egg masses into a cup.

A putty knife, plastic knife or similar object can be used to gently scrape spongy moth egg masses into a cup of soapy water. The water can be discarded after two days. / Photo Credit: Wisconsin DNR

By Bill McNee, DNR Forest Health Specialist, Oshkosh
Bill.McNee@wisconsin.gov

The Wisconsin Department of Natural Resources (DNR) encourages property owners to examine their trees for spongy moth egg masses and determine whether control measures are needed this spring.

Property owners who have oak, birch, crabapple, aspen, willow and linden (basswood) trees should be particularly watchful because the caterpillars of this invasive insect prefer these species. However, they will feed on many other kinds of trees and shrubs.

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Oak Wilt Information Updated

Posted on by akabelowsky
University of Wisconsin-Madison Extension online tool to help with oak wilt decisions.

A University of Wisconsin-Madison Extension online tool provides users localized information about the estimated emergence status of the two most important insects that transmit oak wilt in Wisconsin. / Graphic Credit: University of Wisconsin-Madison Extension

By Kyoko Scanlon, DNR Forest Pathologist, Fitchburg
Kyoko.Scanlon@wisconsin.gov

In 2025, oak wilt was detected for the first time in Hughes Township, Bayfield County, a northern Wisconsin location where oak wilt remains uncommon. There were no new county finds in 2025.

Based on the findings in 2025, the maps in the Oak Harvesting Guidelines To Reduce The Risk Of Introduction And Spread Of Oak Wilt (the oak wilt guidelines), oak wilt fact sheet and were updated. The maps in the oak wilt guidelines are good through the end of 2026.

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Oak Wilt High Risk Period Quickly Approaches

Posted on by akabelowsky
A closeup of a fungal pressure pad under the bark of an oak tree infected with oak wilt.

A fungal pressure pad formed on the outside of the sapwood underneath the bark of an infected tree. The pad will create cracks in the bark, where beetles can enter and visit the pad and become covered in spores. They will then leave and move on to infect new trees through open wounds. / Photo Credit: Wisconsin DNR

By Alex Hornung, DNR Forest Health Specialist, Plover
Alexandra.Hornung@wisconsin.gov or 715-340-3810

It is again that time of year to pause operating in oak stands or pruning oak trees during the high-risk period for oak wilt, which begins in April. The high-risk period begins April 1 in the South, April 15 in the North, and ends in both zones on July 15.

The high-risk period is determined by when the beetles that carry the fungus that causes oak wilt have emerged for the year and when they are carrying the highest number of fungal spores. When wounds are created by logging operations or other activities that expose sapwood, the beetles carry the fungus to the wounded tree, and the disease process begins.

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Forest Health Annual Report Hot Off The Presses

Posted on by akabelowsky
The cover of the 2025 Wisconsin Department of Natural Resources Forest Health Annual Report.

The cover of the 2025 Wisconsin Department of Natural Resources Forest Health Annual Report. / 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 (DNR) has made its 2025 Forest Health Annual Report ready to view and download.

This year’s edition contains 55 pages of reporting on forest health issues throughout Wisconsin, detailing methods employed by the DNR and other agencies to control pests, diseases and invasive plants.

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Shively, McNee To Make Public Appearances

Posted on by akabelowsky
Tim Shively, the Wisconsin Department of Natural Resources Forest Health specialist for the West Central zone.

Tim Shively, the Wisconsin Department of Natural Resources Forest Health specialist for the West Central zone. / Photo Credit: Wisconsin DNR

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

Tim Shively, the Wisconsin Department of Natural Resources (DNR) Forest Health specialist for West Central Wisconsin, will give a presentation titled “Forest Health for Everyone” at a meeting of the Juneau County Men’s Shed at 10 a.m. Tuesday, Jan. 27, in Mauston.

The event is part of a program put on by the Aging and Disability Resource Center of Eagle Country, and will take place at W4890 County Hwy. N, Mauston. It is open to the public. Continue reading “Shively, McNee To Make Public Appearances” →

White Pine Blister Rust Can Devastate Young Stands

Posted on by akabelowsky

By Tim Shively, DNR Forest Health Specialist
Timothy.Shively@wisconsin.gov or 608-772-6974

A close-up photo of a white pine blister rust canker as seen on a young white pine tree.

A white pine blister rust canker as seen on a young white pine tree. / Photo Credit: Wisconsin DNR

Eastern white pine (Pinus strobus) has historically held great ecological, cultural and economic value throughout Wisconsin, a tradition which continues today. For more than 100 years, however, it has been threatened by a non-native, invasive fungal pathogen called Cronartium ribicola, or white pine blister rust (WPBR).

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Watch For Woodpecker Damage On Ash Trees

Posted on by akabelowsky
Woodpecker flecking on the bark of a dying ash tree is visible at Winnebago County Community Park in Oshkosh.

Woodpecker flecking on the bark of a dying ash tree is visible at Winnebago County Community Park in Oshkosh. Flecking occurs when the birds peck away at the trees to feed on emerald ash borer larvae beneath the bark. / Photo Credit: Wisconsin DNR

By Bill McNee, DNR Forest Health Specialist
Bill.McNee@wisconsin.gov

The Wisconsin Department of Natural Resources (DNR) encourages property owners to watch for woodpecker damage to their ash trees this winter.

Woodpecker damage, often called “flecking,” happens when birds peck away some of a tree’s bark to access the larvae underneath. Flecking is a common early sign that an ash tree might be infested with emerald ash borer (EAB), an invasive insect. EAB is the most damaging threat to Wisconsin trees, killing more than 99% of the untreated ash trees it infests.

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Increased Tree Mortality Seen As Spongy Moth Outbreak Ends

Posted on by akabelowsky
Mature spongy moth larva on a tree at Potawatomi State Park in Door County, July 2025.

Mature spongy moth larva on a tree at Potawatomi State Park in Door County, July 2025. / Photo Credit: Wisconsin DNR

By Bill McNee, DNR Forest Health Specialist, Oshkosh
Bill.McNee@wisconsin.gov  

Wisconsin’s recent period of high spongy moth populations (an “outbreak”) came to an end in 2025, as the remaining known hotspots were aerially sprayed or naturally collapsed. Only a handful of large larvae were observed or reported by property owners.

Spongy moth populations are likely to be low across the state for at least the next few years. However, it is possible that some sites may experience a population increase before then, if local weather conditions are favorable for the insect.

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DNR Tree And Shrub Seedling Sales To Begin Oct. 6

Posted on by janness

The Wisconsin Department of Natural Resources (DNR) is accepting seedling orders from Wisconsin landowners for trees and shrubs to be planted in spring 2026, starting Oct. 6, 2025.

Wisconsin forest nurseries have provided high-quality, native tree seedlings, appropriate for planting throughout Wisconsin, for over 100 years. Seedlings grown at the state nurseries are used for reforestation and conservation plantings on private, industrial, tribal and public lands. Continue reading “DNR Tree And Shrub Seedling Sales To Begin Oct. 6” →

Bur Oak Blight Confirmed In Calumet County

Posted on by akabelowsky
Photo of a wedge-shaped area of dead tissue at the tip of a bur oak leaf from a tree infected with bur oak blight.

A wedge-shaped area of dead tissue at the tip of a bur oak leaf from a tree infected with bur oak blight. / Photo Credit: Wisconsin DNR

By Bill McNee, DNR Forest Health Specialist, Oshkosh
Bill.McNee@wisconsin.gov

Recent laboratory examination has confirmed the presence of bur oak blight in Calumet County. The disease affects only bur oaks and is caused by the fungus, Tubakia iowensis.

Calumet County is the 35th Wisconsin county to have a confirmed detection of bur oak blight. The disease has not been microscopically confirmed in all counties where bur oak grows and is likely present in additional counties. Bur oak blight was first reported in Midwestern states in the 1990s.

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