Central WI Forest Health

Jack Pine Budworm Outbreak Subsides

Posted on by akabelowsky

By Paul Cigan, DNR Forest Health Specialist, Hayward
Paul.Cigan@wisconsin.gov or 715-416-4920

Aerial view of jack pine budworm defoliation in jack pine stands in Douglas County during the 2023 outbreak. / Photo Credit: Paul Cigan, Wisconsin DNR

Jack pine defoliation caused by the jack pine budworm (JPBW) continued at mostly light levels this year, affecting stands in the Central and Northwest Sands Ecological Regions of Wisconsin.

In the Northwest Sands, jack pine stands experienced light and scattered defoliation across Burnett, Douglas, Polk and Washburn counties. In the Central Sands, JPBW caused moderate to heavy defoliation across roughly 500 acres of jack pine on county and state forests in Jackson County, east of Black River Falls.

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Weather Whiplash Affects Pine Stands

Posted on by akabelowsky
Swath of dead pine due to high water table mortality

A swath of pine dead due to high water table mortality in 2020 in northeast Wisconsin.

By Alex Hornung, DNR Forest Health Specialist, Plover;
Alexandra.Hornung@wisconsin.gov

Many pine stands across central and northeast Wisconsin are being impacted by the change from high levels of precipitation to extreme drought that has occurred over the last 5-7 years.

Drastic or sudden changes can be particularly stressful to trees of all species, but especially to pine stands that prefer well-drained soil types.

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Watch For Spongy Moth Caterpillar Diseases

Posted on by akabelowsky

By Bill McNee, DNR Forest Health Specialist, Oshkosh
Bill.McNee@wisconsin.gov or 920-360-0942

With this spring’s weather bringing above-average rainfall across most of Wisconsin, we will likely see moderate to heavy mortality of spongy moth caterpillars at many locations this summer.

Last year, the statewide May-June period was the third-driest since recordkeeping began in the late 1800s, according to the NOAA National Centers for Environmental Information. As a result, the effectiveness of the caterpillar-killing fungus, Entomophaga maimaiga, was limited. Spring 2024 is noticeably wetter, and thus, increased effectiveness of E. maimaiga is likely.

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Woodpecker Damage On Ash Trees May Indicate Emerald Ash Borer

Posted on by akabelowsky

By Bill McNee; DNR Forest Health specialist, Oshkosh;
Bill.McNee@wisconsin.gov or 920-360-0942

Photo showing woodpecker damage on an ash tree trunk, an early sign the tree might be infested with emerald ash borer.

Woodpecker damage is an early sign an ash tree might be infested with emerald ash borer. / Photo Credit: Wisconsin DNR

The Wisconsin Department of Natural Resources (DNR) encourages property owners to watch for woodpecker damage to their ash trees this winter. If damage is found, property owners should make plans to take action in the spring.

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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Forest Health Forecast For 2024

Posted on by akabelowsky

Paul Cigan, DNR Forest Health Specialist, Hayward;
Paul.Cigan@wisconsin.gov or 715-416-4920

An aerial photo of oak and aspen forests showing heavy defoliation from spongy moth.

Oak and aspen forests with heavy defoliation from spongy moth. Additional defoliation coupled with ongoing drought in the upcoming 2024 growing season is expected to put significant stress on affected forests. / Photo Credit: Paul Cigan, Wisconsin DNR

Maintaining a healthy and productive forest often requires — more than ever before — a working knowledge of how to anticipate, prevent and mitigate environmental stressors that threaten to undermine it. The list of stressors includes drought, impact of forest insects and diseases.

In a recent and timely article, Denise Thornton of My Wisconsin Woods taps the expansive knowledge of the DNR’s Forest Health team and a state climatologist to bring focus to the threats facing forests this year.

She also lists steps that can be taken to ensure health and proactivity are maintained in your forests.

Green Light On For Oak Tree Work

Posted on by akabelowsky
Photo of fallen leaves from a red oak that show discoloration, an indication that the tree is infected with oak wilt.

Discolored fallen leaves from a red oak tree indicate that the tree is infected with oak wilt. / Photo Credit: Wisconsin DNR

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

With the weather taking its time to turn wintry, it’s a good time to remind landowners and work crews that now through the end of March is an ideal time to perform pruning, trimming and brush removal on and near oak trees.

This is a low-risk period for the trees to be infected with oak wilt, a fungal disease spread by beetles. When a red oak is infected with oak wilt, it will die that year. The disease also stresses white oaks, often proving fatal.

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Diseases Take Aim At Spongy Moth

Posted on by akabelowsky
Photo of tree showing caterpillars killed by virus and fungus

Caterpillars killed by nucleopolyhedrosis virus (NPV) hang in an inverted “V” orientation; caterpillars killed by the fungus Entomophaga maimaiga hang vertically. Photo: Wisconsin DNR.

By Bill McNee, DNR Forest Health Specialist, Oshkosh
bill.mcnee@wisconsin.gov or 920-360-0942

With this spring’s dry weather in Wisconsin came predictions of the largest spongy moth population in years.

When spongy moth populations are high, we often see heavy mortality of the larger caterpillars due to two pathogens. Heavy caterpillar mortality will reduce the severity of the following year’s outbreak and often causes a population crash during the current year. If a heavy die-off of caterpillars is observed, please let your local DNR Forest Health Specialist know about it.

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Spongy Moth Focus Of Video, Webcast

Posted on by akabelowsky

Art Kabelowsky, DNR Forest Health outreach and communications specialist
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

Add “YouTube Influencer” to the long list of career accomplishments of Andrea Diss-Torrance, Ph.D.

With the spongy moth caterpillar population on the rise in many areas of Wisconsin this season, the Wisconsin Department of Natural Resources stepped into action last month.

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Look For Spongy Moth Egg Masses – Larger Outbreak Possible in 2023

Posted on by kirsten.biefeld

By: Bill McNee, DNR Forest Health Specialist, Oshkosh

bill.mcnee@wisconsin.gov or 920-360-0942

Three tan-colored spongy moth egg masses on a single tree branch in Walworth County.

Three spongy moth egg masses on a branch in Walworth County. Photo Credit: Bill McNee, Wisconsin DNR

Now that spongy moth* (formerly known as gypsy moth) egg laying is complete for 2022, it’s a good time to look for and dispose of egg masses produced by adult moths over the past two months.

Spongy moth egg masses are tan-colored lumps about the size of a nickel or quarter, and are found on trees, buildings and other outdoor objects. They may also be found in protected places such as firewood piles and birdhouses. Newly produced egg masses will feel firm and appear darker in color than older egg masses, which appear faded, feel spongy and do not contain viable eggs. The current-year egg masses will not hatch until next spring.

In 2022, Wisconsin’s spongy moth population grew for a third consecutive summer due to favorable weather conditions and limited caterpillar mortality from diseases. The outbreak was most dramatic in opposite ends of the state. In southern and southeast Wisconsin, several thousand oak-dominated acres were heavily defoliated and very large numbers of property owner reports were received by DNR staff. In Bayfield County, about 80,000 acres of rural defoliation was reported from aspen-dominated forests. Smaller patches of defoliation were also reported from several other counties. Continue reading “Look For Spongy Moth Egg Masses – Larger Outbreak Possible in 2023” →

Spruce Budworm, Balsam Fir Sawfly, And Yellowheaded Spruce Sawfly

Posted on by patricialindquist

Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665. 

The spruce budworm outbreak continues this year, but the amount of visible defoliation is generally lower than last year. Some areas of the Northwoods have severe defoliation this year, but in many other areas, the amount of new, green foliage far exceeds the amount of defoliation.

In areas where the defoliation appears less severe, you can still find plenty of caterpillars, but the new foliage is less eaten than anticipated. The late spring frost/freeze may have killed some caterpillars, or the long cool spring may have delayed bud-break enough that the caterpillars did most of their feeding on older foliage before the new foliage expanded. 

The spruce budworm outbreak in Wisconsin started in 2012, and outbreaks typically last about 10 years.  Mortality of balsam fir trees started to show up last year following several years of significant defoliation. Even with new growth on the trees this year, they may continue to decline, and mortality could still occur. 

Spruce branches showing defoliation, older needles and new, bright green needles.

Defoliation is still present, but there is lots of new growth on balsam fir this year in many areas of northern Wisconsin.

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