Southern WI Forest Health

Forest Health Staff To Join Oak Disease Webinar

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A screen grab of a webpage on the United States Environmental Protection Agency website discussing a pest management webinar set for Dec. 10, 2024.

The U.S. Environmental Protection Agency will present an international webinar titled “Deadly Oak Diseases” from 1 to 2:30 p.m. Tuesday, Dec. 10. / Graphic Credit: U.S. Environmental Protection Agency

By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg;
Michael.Hillstrom@wisconsin.gov

The U.S. Environmental Protection Agency (EPA) will present an international webinar titled “Deadly Oak Diseases” from 1 to 2:30 p.m. (CST) Tuesday, Dec. 10.

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Forest Health Staff Public Appearance Set

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Wisconsin Department of Natural Resources Forest Health team leader Becky Gray will discuss invasives during a presentation to the Southeastern Wisconsin Invasive Species Consortium, set for Wednesday, Nov. 6, at Havenwoods State Forest in Milwaukee. / Photo Credit: Art Kabelowsky, Wisconsin DNR

Forest Health team leader Becky Gray has planned an appearance at a public meeting of the Southeastern Wisconsin Invasive Species Consortium (SEWISC). She’ll give a presentation covering invasives on a statewide level.

The event will take place from 1 to 4 p.m. Wednesday, Nov. 6, at Havenwoods State Forest, 6141 N. Hopkins St., Milwaukee, WI. More information is available on the SEWISC website.

Check Conifers For Invasive Adelgids

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Photo showing white, cottony hemlock woolly adelgid egg sacs on a hemlock branch.

White, cottony hemlock woolly adelgid egg sacs on a hemlock branch. / Photo Credit: Bill McNee, Wisconsin DNR

By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg; Michael.Hillstrom@wisconsin.gov

Hemlock woolly adelgid (HWA) and balsam woolly adelgid (BWA) are invasive, aphid-like insects that cause tree mortality in North America. Neither has been found in Wisconsin so far, but they are likely to arrive at some point, as they have been confirmed in Michigan.

HWA (Adelges tsugae) is an invasive, sucking insect pest of hemlock trees. The white, cottony egg sacs of HWA can be seen on the undersides of hemlock branches at the base of needles year-round. HWA saliva enters the tree while feeding. The saliva is toxic and causes needle drop and twig dieback, progressing to tree mortality in 4-10 years.

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A Busy Summer For Urban Forestry Interns

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By Dan Buckler, DNR Urban Forest Assessment Specialist; daniel.buckler@wisconsin.gov or (608) 445-4578

Every year, the summer ends faster than one could pronounce Liquidambar styraciflua, and this year was no exception. Hopefully, while you are trying to recall proper Latin pronunciations, your summer is still filled with enjoyable, productive or illuminating activities. That was certainly the case for the DNR Urban Forestry summer internship program. This summer, staff worked with Southern University students Taylor Colman and Priscilla Loh on a variety of different data collection projects, filling the internship’s eight weeks with species identification, tree mensuration and tree health assessments. Continue reading “A Busy Summer For Urban Forestry Interns” →

Spruce Budworm Defoliation Continues

Posted on by akabelowsky

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

Closeup photo showing that webbing created by the spruce budworm caterpillar holds needles and frass and protects the caterpillar. A pupa hangs from the branch.

Webbing created by the spruce budworm caterpillar holds needles and frass and protects the caterpillar. A pupa hangs from the branch. / Photo Credit: Linda Williams, Wisconsin DNR

Although symptoms weren’t as prevalent as in 2023, this year marked yet another year of defoliation from spruce budworm.

Another severe year of defoliation causes additional stress on the trees. Even though there has been a lot of rainfall this spring, it’s still stressful for the trees to face repeated years of defoliation by spruce budworm before they begin to decline and die.

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Dropping Leaves May Indicate Oak Wilt

Posted on by akabelowsky

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

Photo showing that oak leaves that drop from a tree infected with oak wilt may be all brown or all green, or often they will have green near the base of the leaf and the outer portions will be brown or watersoaked green.

Oak leaves that drop from a tree infected with oak wilt may be all brown or all green, or often they will have green near the base of the leaf and the outer portions will be brown or watersoaked green. / Photo Credit: Linda Williams, Wisconsin DNR.

The middle of summer is the time to start watching oak trees for symptoms of oak wilt. Although symptoms show up suddenly and leaves drop quickly, symptoms can emerge anytime between now and when leaves turn color in the fall.

Trees that were wounded in the spring and became infected with the fungus that causes oak wilt will usually die that same year. In established oak wilt pockets, the fungus moves underground through grafted root systems and trees will wilt as the fungus moves into the tree.

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Tubakia Leaf Disease Affects Red Oak

Posted on by akabelowsky

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

A tree showing that lower branches are thin and have lost leaves due to Tubakia leaf spot, while leaves on its upper branches look good.

A tree showing that lower branches are thin and have lost leaves due to Tubakia leaf spot, while leaves on its upper branches look good. / Photo Credit: Linda Williams, Wisconsin DNR.

Tubakia leaf spot is a leaf disease caused by a fungus (Tubakia dryina) that typically affects the lower canopy of red oaks.

Because of all the rain that came during the spring and early summer of 2024, the fungus has started to impact some trees. Problems didn’t occur last year because the weather was too dry.

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Spongy Moth Status Update

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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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‘Cicadapalooza’ Makes Noise In Lake Geneva

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Photo showing dozens of recently emerged cicadas rest on a tree trunk at Big Foot Beach State Park in Lake Geneva on May 30, 2024.

Dozens of recently emerged cicadas rest on a tree trunk at Big Foot Beach State Park in Lake Geneva on May 30, 2024. / Photo Credit: Sarah Wolski, Wisconsin DNR

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

Brood XIII periodical cicadas apparently love Lake Geneva. The Wisconsin hotspot for Brood XIII has again been the resort city of Lake Geneva, located just a few miles from the Illinois border. It experienced Wisconsin’s first emergence of the insects’ latest 17-year cycle on May 17. Cicadas remained active – noisily so – through late June.

The city of Lake Geneva, joined by the University of Wisconsin-Madison Entomology department, celebrated the insects’ return with Cicadapalooza, a family-friendly, free pop-up event on June 8 that included guided walking tours, presentations by UW-Madison entomologists, cicada merchandise, food and more.

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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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