Insect

Periodical Cicada Damage Now Visible

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

Photo of Brood XIII periodical cicadas (Magicicada spp.) resting on a tree at Big Foot Beach State Park in Lake Geneva on June 12, 2024.

Brood XIII periodical cicadas (Magicicada spp.) rest on a tree at Big Foot Beach State Park in Lake Geneva on June 12, 2024.

Scattered twig death, commonly known as “flagging,” was recently observed on several trees at Big Foot Beach State Park in Walworth County, where large numbers of 17-year Brood XIII periodical cicadas (Magicicada spp.) were present. This flagging is likely present in other localized sites in southern Wisconsin that experienced high numbers of cicada emergences.

The University of Wisconsin-Madison Insect Diagnostic Lab’s Periodical Cicadas in Wisconsin webpage has more information about the periodical cicada outbreak.

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Oak Moth Outbreaks May Have Peaked In North

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

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

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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Spongy Moth Egg Mass Surveying Video Released

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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DNR Debuts Fact Sheet On Twolined Chestnut Borer

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

The Wisconsin Department of Resources (DNR) has debuted a new Forest Health fact sheet on twolined chestnut borer (Agrilus bilineatus), a native beetle that attacks already weakened oaks in Wisconsin.

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Spongy Moth Resource Center Hatches Just In Time

By Art Kabelowsky, DNR forest health communications and outreach specialist, Fitchburg
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

A screenshot of the mock-up of the new Spongy Moth Resource CenterAs Wisconsin braces for another potentially busy season of spongy moth caterpillars, three state agencies have teamed up to make it easier for tree owners and others to access the latest information and advice on the invasive, leaf-chomping pests.

The Wisconsin Department of Natural Resources (DNR) has joined the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) and the University of Wisconsin-Madison Extension to revamp the state’s interagency spongy moth information webpage.

Renamed the “Spongy Moth Resource Center,” a first glance at the document reveals basic information on the insect. But by following a new list of “Frequently Asked Questions,” visitors can tunnel deeper to more easily find information that applies specifically to their situation.

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Emerald Ash Borer Detected In Washburn, Taylor Counties

By Paul Cigan, DNR forest health specialist, Hayward;
Paul.Cigan@wisconsin.gov or 715-634-9232

Photo of an emerald ash borer on a tree

The emerald ash borer was detected in the Wisconsin counties of Taylor and Washburn in April, making them No. 70 and No. 71 of Wisconsin’s 72 counties that have confirmed presence of the invasive insect.

The emerald ash borer (EAB) has been detected for the first time in Washburn and Taylor counties, making them the No. 70 and No. 71 of Wisconsin’s 72 counties to have a confirmed detection of the invasive insect.

Here are the details of the most recent discoveries: Continue reading “Emerald Ash Borer Detected In Washburn, Taylor Counties”

UW-Madison Launches Website About Cicadas

By Krista Hamilton, Wisconsin Department of Agriculture, Trade and Consumer Protection;
Krista.Hamilton@wisconsin.gov

Photo of cicadas on a plant.

Hungry cicadas are expected to emerge from their 17-year dormancy this month to feed and mate. In past emergences, Brood XIII cicadas have been documented in 11 southern Wisconsin counties. / Photo Credit: Jim Occi, BugPics, Bugwood.org

In anticipation of the emergence of the Brood XIII periodical cicada this spring, the University of Wisconsin-Madison introduced a new Wisconsin Periodical Cicada website.

Information on the site covers the biology, ecology and distribution of these insects using photos, historical videos and other useful resources.

UW-Madison entomologist PJ Liesch sifted through 150 years of books, newspaper articles, university studies, government records and specimens in the Wisconsin Insect Research Collection to develop an updated map of Wisconsin periodical cicada reports.

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USDA Seeks Donated Ash Trees To Battle Emerald Ash Borer

By Caleb Burden, Acting Field Lead Technician, USDA APHIS PPQ;
Caleb.Burden@usda.gov or 734-732-0025

Photo of a green ash tree with a small piece of bark cut back shows emerald ash borer larvae feeding on the tree.

A green ash tree with a small piece of bark cut back shows emerald ash borer larvae feeding on the tree. / Photo Credit: USDA APHIS PPS

In the fight against emerald ash borer (EAB), the United States Department of Agriculture (USDA) again asks Wisconsin landowners to donate live, EAB-infested ash trees for use in a biological control program.

The emerald ash borer is an invasive insect from Asia first detected in the United States in 2002. Following its discovery, EAB has caused the death and decline of tens of millions of ash trees.

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