Pest

Make Plans Now To Fight Spongy Moth In 2025

Posted on by akabelowsky
A photo showing large egg masses on a tree at the Kettle Moraine State Forest-Southern Unit in 2021.

Large egg masses are seen on a tree at the Kettle Moraine State Forest-Southern Unit in 2021. / Photo Credit: Bill McNee, Wisconsin DNR

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

Part Two of a report on spongy moth in Wisconsin in 2024 and 2025. Part One was published in December.

The Wisconsin Department of Natural Resources (DNR) is encouraging property owners to examine their property for spongy moth egg masses and plan for action this spring if needed. Each spongy moth egg mass contains hundreds of eggs that will hatch into hungry, leaf-eating caterpillars this spring. Large numbers of these invasive caterpillars can be a tremendous nuisance that may cause tree mortality.

Continue reading “Make Plans Now To Fight Spongy Moth In 2025” →

Woodpecker Flecking On Ash Means EAB

Posted on by akabelowsky
Photo showing that woodpecker flecking on green ash and white ash, from birds feeding on emerald ash borer larvae, will often be extensive and very noticeable.

Woodpecker flecking on green ash and white ash, from birds feeding on emerald ash borer larvae, will often be extensive and very noticeable. / Photo Credit: Linda Williams, Wisconsin DNR

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

Ash trees that are flecked by woodpeckers will have the outer layers of their bark chipped off by the birds. Woodpeckers do this to punch through the remaining bark more easily to get at the tasty emerald ash borer (EAB) larvae living there.

Flecking usually starts at the top of the tree, providing a sure sign that insects are under the bark. Although the problem could be caused by ash bark beetles, the more common culprit is EAB.

Continue reading “Woodpecker Flecking On Ash Means EAB” →

White Masses On Alder Are Woolly Aphids

Posted on by akabelowsky
Photo showing a group of woolly alder aphids on an alder branch.

A group of woolly alder aphids on an alder branch. / Photo Credit: Linda Williams, Wisconsin DNR

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

Have you seen white lumps of fluff on alder stems? Woolly alder aphids congregate together for the winter. These aphids produce white filaments from their bodies to protect them from predators. When they congregate, they can look like a big clump of snow stuck to alder branches.

Continue reading “White Masses On Alder Are Woolly Aphids” →

2024 Spongy Moth Review

Posted on by akabelowsky

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

A tree shows high numbers of spongy moth caterpillars, though the majority of the caterpillars have been killed either by virus (hanging in an inverted V) or fungus (hanging in a stretched line, head down). The virus and fungus helped to quell a potential outbreak in many areas of the state in 2024.

A tree shows high numbers of spongy moth caterpillars, though the majority of the caterpillars have been killed either by virus (hanging in an inverted V) or fungus (hanging in a stretched line, head down). The virus and fungus helped to quell a potential outbreak in many areas of the state in 2024. / Photo Credit: Bill McNee, Wisconsin DNR

As the 2023 spongy moth season ended, there were hopes for a return to colder and wetter conditions in 2024 so that the spongy moth outbreak would decline or even come to an end.

What wound up happening in Wisconsin was the “lost winter,” the warmest since recordkeeping began in 1895. Given this warmth, there were concerns that the widespread spongy moth outbreak would continue for a third consecutive summer, with good caterpillar survival, ongoing defoliation and high rates of tree mortality in already stressed forests.

Continue reading “2024 Spongy Moth Review” →

Cooperative Enlists Public To Make Tree Health A Snap

Posted on by akabelowsky

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

Screenshot of the main page of the TreeSnap app as seen on a mobile phone.

The main page of the TreeSnap app as seen on a mobile phone. / Photo Credit: TreeSnap.org

It takes more than a village to foster healthy forests. More than a township, a city and a county, too. Sometimes, even more than a state.

That’s why the Great Lakes Basin Forest Health Cooperative (GLB FHC) was formed four years ago by Holden Arboretum in Ohio and the U.S. Department of Agriculture Forest Service.

Geographically, the group’s region encompasses an area from New Jersey to Wisconsin. The Wisconsin Department of Natural Resources (DNR) is an active member.

Continue reading “Cooperative Enlists Public To Make Tree Health A Snap” →

Forest Health and Climate Change Resources

Posted on by akabelowsky

By Carmen Hardin, Director, DNR Applied Forestry Bureau, Rhinelander;
Carmen.Hardin@wisconsin.gov

A graphic shows changing tornado risk trends in the United States from 1980 to 2020. All Wisconsin counties are showing an increase in tornado days.

A graphic shows changing tornado risk trends in the United States from 1980 to 2020. All Wisconsin counties are showing an increase in tornado days. / Map Credit: Inside Climate News, Stephen M. Strader et. al., Nature Magazine

We are often asked difficult questions about our forests, their health and how climate change is impacting them. Here is a curated collection of resources that may help you answer some of those questions. Continue reading “Forest Health and Climate Change Resources” →

Treatment Of EAB Infestations In Yard Trees

Posted on by akabelowsky

By Abby Krause, DNR Urban Forestry Coordinator;
Abigail.Krause@wisconsin.gov or 608-556-5690

This summer’s detection of emerald ash borer (EAB) in Burnett County means our little metallic friend (or should I say foe?) is now known to be present in all 72 Wisconsin counties.

While EAB has been around for the better part of two decades in Wisconsin, many homeowners are still in the thick of dealing with the fallout of this invasive pest.

Continue reading “Treatment Of EAB Infestations In Yard Trees” →

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.

Continue reading “Forest Health Staff To Join Oak Disease Webinar” →

Check Conifers For Invasive Adelgids

Posted on by akabelowsky
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.

Continue reading “Check Conifers For Invasive Adelgids” →

Winter Squirrel Damage Killing Maple Branches

Posted on by akabelowsky

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

Two photos show maple branches that died recently due to previous damage from squirrels.

Two photos show maple branches that died recently due to previous damage from squirrels. / Photo Credit: Linda Williams, Wisconsin DNR

Have you noticed maple branches suddenly dying this summer?

Sudden mortality of maple branches during the summer in northern Wisconsin is often a result of squirrel damage that occurred in late winter and early spring.

In late winter and early spring, gray squirrels strip the bark of maples to get at the sweet maple sap. When the damage is extensive or severe, entire trees or branches will be killed immediately and will not leaf out in the spring.

Continue reading “Winter Squirrel Damage Killing Maple Branches” →