Woodland owners

Basswood Trees Short On Leaves Due To Thrips

Posted on by akabelowsky

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

Photo showing Basswood leaves that have been damaged due to the feeding of introduced basswood thrips.

Basswood leaves show damage due to the feeding of introduced basswood thrips. / Photo Credit: Linda Williams, Wisconsin DNR

For the third consecutive year, damage from introduced basswood thrips (Thrips calcaratus) is significant in some areas of northeast Wisconsin, especially Forest County.

Introduced basswood thrips are tiny, invasive insects that feed inside tree buds in early spring. The feeding causes leaves to deform when they expand, looking like they suffered frost or wind damage.

Continue reading “Basswood Trees Short On Leaves Due To Thrips” →

Keep An Eye Out For Beech Leaf Disease

Posted on by akabelowsky

By Kyoko Scanlon, DNR Forest Pathologist, Fitchburg;
Kyoko.Scanlon@wisconsin.gov or 608-235-7532

Forest owners and land managers should look for beech leaf disease (BLD) this summer, a destructive beech tree disease in the United States.

The disease is primarily found on American beech (Fagus grandifolia) but can also be found on ornamental species such as 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 nearby states highlight the continued importance of monitoring BLD’s expansion. There is potential for BLD to move into Wisconsin as the eastern portion of the state overlaps with the native range of American beech.

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Five Years Later, Effects Of Derecho Remain

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

Over the night of July 19-20, 2019, Mother Nature carved a massive swath of destruction through northern Wisconsin.

Today, after years of hard work cleaning up after the massive derecho windstorm of ’19, local foresters, work crews and landowners have only begun to understand the breadth and depth of the damage as they process the lessons learned.

In many areas, the recovery work remains incomplete. Some of that forest damage will never receive direct attention.

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Oak Moth Outbreaks May Have Peaked In North

Posted on by akabelowsky

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

Wide-angle photo showing many oaks across northern Wisconsin with partially defoliated, thin, and yellow-tinted crowns caused by defoliation from the oak leafroller and oak leaftier.

Many oaks across northern Wisconsin displayed partially defoliated, thin, and yellow-tinted crowns caused by defoliation from the oak leafroller and oak leaftier. / Photo Credit: Paul Cigan, Wisconsin DNR

A three-year-long outbreak of oak leafroller moth and oak leaftier moth—two native, early-season oak defoliators—continued this spring in northern Wisconsin, leaving behind tens of thousands of acres of oak-dominated forest with scattered, widespread defoliation.

Partially defoliated, thin and yellow-tinted crowns were visible across portions of Barron, Rusk, Sawyer and Washburn counties, as well as areas in Florence, Forest, northern Marinette and Vilas counties.

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Spongy Moth Status Update

Posted on by akabelowsky

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

A photo showing several trees with spongy moth defoliation in Marinette County in mid-June 2024.

Spongy moth defoliation in Marinette County in mid-June 2024. / Photo Credit: Darrek Sams, Wisconsin DNR

As of early July, we have seen a mix of live and dead caterpillars and tree defoliation that is typical of a late-stage spongy moth outbreak. Reports of defoliation have been received as far north as Florence County.

Recent aerial surveys in southern Wisconsin spotted defoliation in the same general areas as in 2023, but the defoliation has generally been less intense this year. Information for northern Wisconsin has yet to be made available. Refoliating oaks, growing a second set of pale-looking leaves, were seen in Walworth County in early July.

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Spongy Moth Egg Mass Surveying Video Released

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

The Wisconsin Department of Natural Resources (DNR) Forest Health team joined with the DNR Office of Communications to produce an instructional video aimed at helping large landowners and land managers in the fight against spongy moth.

The video, less than 2 minutes in length, shows how to conduct a survey of spongy moth egg masses in the fall. With that information, people can predict how much damage to expect from the caterpillars in the spring, giving them time to make advance plans for the most effective control options.

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Watch For Spongy Moth Caterpillar Diseases

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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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Retracted: Study Shows Drought Harms Wetter Forests Most

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Note:

The original version of this Forest Health News article has been removed because the journal article in Science magazine that was referenced has been retracted by its authors due to a mathematical error. The journal authors reran their analysis and although many results remained unchanged, the statistical significance of some conclusions, and the results of some robustness tests, did change. It is unclear to what degree these errors affected observations in the Forest Health News article, so that article was removed. More information is available here.

Avoid Hitchhikers This Summer

Posted on by akabelowsky

By Erika Segerson-Mueller, DNR invasive plant program specialist, Oshkosh
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Invasive jumping worms have a light-colored clitellum, while most worm species have a raised, pink clitellum. / Photo Credit: Brad Herrick, UW-Madison Arboretum

To reiterate some advice you may have heard long ago from your parents: Don’t give rides to hitchhikers. They may have been thinking about people, but hitchhiking invasive plants, insects and pathogens are also worthy of concern.

As you dream of days spent at the cabin up north, planting your garden or wandering in the woods, here are a few reminders to help you avoid bringing hitchhiking invasives along as you enjoy your spring and summer activities. Continue reading “Avoid Hitchhikers This Summer” →

Phomopsis Galls Found On Northern Red Oak

Posted on by akabelowsky

By Linda Williams, DNR forest health specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665

Photo showing large Phomopsis galls on a tree before it has leafed out in the spring.

It is often easier to spot large Phomopsis galls before leaves come out in the spring.

Phomopsis galls are large woody swellings on the branches or main stem caused by a fungus. Across Wisconsin, Phomopsis galls can grow on hickory, especially bitternut hickory. However, in some areas of Wisconsin, they can occur on northern red oak.

Northern red oaks sometimes have hundreds of Phomopsis galls on the branches, ranging from as small as a tennis ball to as large as a basketball. Continue reading “Phomopsis Galls Found On Northern Red Oak” →