Statewide Forest Health

Japanese Beetles Finding New Locations

Posted on by akabelowsky

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

A closeup photo of Japanese beetles defoliating basswood leaves. The invasive pest is becoming more prevalent in northern Wisconsin.

A closeup photo of Japanese beetles defoliating basswood leaves. The invasive pest is becoming more prevalent in northern Wisconsin. / Photo Credit: Linda Williams, Wisconsin DNR

The Japanese beetle (Popillia japonica) is an invasive insect that feeds on many plant species. The pests “skeletonize” leaves by eating the material between the veins.

Adult Japanese beetles feed on the flowers and leaves of more than 300 plant species, including trees, shrubs and herbaceous plants. Forest trees can be defoliated, with open-grown or edge trees suffering the highest defoliation rates.

Continue reading “Japanese Beetles Finding New Locations” →

Oak Decline Continues In Southern Wisconsin

Posted on by akabelowsky

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

Oak decline at Big Foot Beach State Park caused by flooding, drought, spongy moth defoliation, twolined chestnut borer and Armillaria. / Photo Credit: Michael Hillstrom, Wisconsin DNR

Bur and white oaks, most of them more than 100 years old, have experienced rapid mortality (within one to two years) over the past four years in southern Wisconsin and neighboring states. Research into the cause is ongoing, but the evidence so far suggests it’s an oak decline.

Oak declines are not caused by a single issue, but rather by the stacking of multiple health issues. Drought, flooding, storm damage, age, twolined chestnut borer, Armillaria and other root pathogens, and spongy moth and oak leafroller defoliation all play a role in the damage.

Continue reading “Oak Decline Continues In Southern Wisconsin” →

Bark Beetles Infest Drought-Stressed Conifers

Posted on by akabelowsky

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

An adult bark beetle found infesting a white pine branch in 2024. / Photo Credit: Michael Hillstrom, Wisconsin DNR

Conifer mortality in southern Wisconsin has increased in 2024. Regardless of the conifer species, the common theme has been heavy infestation by bark beetles.

This increased bark beetle activity is likely linked to the 2023 drought, which lasted from May to September. Wisconsin experienced the fifth-driest May-July period on record and the fifth-driest meteorological summer (June-August) summer on record. The drought peaked during the middle of September before much-needed rain finally arrived.

Continue reading “Bark Beetles Infest Drought-Stressed Conifers” →

Forest Health Public Appearance Set

Posted on by akabelowsky

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

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.

New Invasive Pest Discovered In Wisconsin

Posted on by akabelowsky

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

A closeup of an elm zigzag sawfly caterpillar consuming a leaf. The invasive insect, new to Wisconsin, was found on an elm tree near the Wisconsin Department of Natural Resources office in Oshkosh on July 16, 2024.

A closeup of an elm zigzag sawfly caterpillar consuming a leaf. The invasive insect, new to Wisconsin, was found on an elm tree near the Wisconsin Department of Natural Resources office in Oshkosh on July 16, 2024. / Photo Credit: Bill McNee, Wisconsin DNR

The invasive insect elm zigzag sawfly (Aproceros leucopada) has been detected in Wisconsin for the first time.

Following the initial Wisconsin discovery in Portage County on July 4. Through Aug. 12, the pest has since been detected in 17 Wisconsin counties. Continue reading “New Invasive Pest Discovered In Wisconsin” →

Emerald Ash Borer Confirmed In All 72 Counties

Posted on by akabelowsky

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

Closeup photo of an adult emerald ash borer. The pest has been detected in Burnett County, making it the 72nd and final county in Wisconsin that have confirmed presence of the invasive insect.

The emerald ash borer has been detected in Burnett County, making it the 72nd and final county in Wisconsin that have confirmed presence of the invasive insect. / Photo Credit: Paul Cigan, Wisconsin DNR

Sixteen years after the Wisconsin Department of Natural Resources (DNR) first detected emerald ash borer (EAB) in Wisconsin, the invasive beetle has been found in the last county without a previous detection.

Burnett County, in northwest Wisconsin, is the 72nd and final county to have a detection of the tree-killing pest.

Continue reading “Emerald Ash Borer Confirmed In All 72 Counties” →

DNR Urban Forestry Council Welcomes New Members

Posted on by janness

The Wisconsin Department of Natural Resources (DNR)’s Division of Forestry recently welcomed two new members to the Wisconsin Urban Forestry Council and said farewell to several members who contributed much to the council. In addition, eight council members renewed their commitment for another 3-year term.

The Wisconsin Urban Forestry Council is an advisory committee to the DNR’s Division of Forestry, guiding the best ways to preserve, protect, expand and improve Wisconsin’s urban and community forest resources. The council is comprised of 23 people appointed by the Secretary of the DNR.

Continue reading “DNR Urban Forestry Council Welcomes New Members” →

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.

Continue reading “Oak Moth Outbreaks May Have Peaked In North” →

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.

Continue reading “Spongy Moth Status Update” →

Best Disposal Methods For Garlic Mustard

Posted on by akabelowsky

By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh Service Center
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Summer can be prime time for invasive plant control, with garlic mustard pulls and many other plant- or location-specific events taking place to confront invasive plants head-on.

Wanting to do your best to help, you might pull garlic mustard along your local hiking trail. But what should you do after you pull it?

Read on for invasive plant disposal tips to ensure you don’t inadvertently do more harm than good with your control efforts.

Continue reading “Best Disposal Methods For Garlic Mustard” →