Forest Health News

Millions Of Cicadas Preparing To Emerge

Posted on by akabelowsky

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

Closeup photo of a periodical cicada, showing its black body and orange-colored wing veins and legs.

Closeup of a periodical cicada, showing its black body and orange-colored wing veins and legs. / Photo Credit: Ward Upham, Kansas State University, Bugwood.org

2024 will be a big year for periodical cicadas (Magicicada spp.).

For the first time since 1803 — when Thomas Jefferson was president — 13-year Brood XIX and 17-year Brood XIII cicadas will co-emerge in the millions.

If you want to observe this spectacle, you can see the Brood XIII cicadas in southern Wisconsin. Expect to see and hear them in June, and bring your ear protection because some of the louder choruses of males can reach 90 decibels.

Continue reading “Millions Of Cicadas Preparing To Emerge” →

Emerald Ash Borer Spreads Through The North

Posted on by akabelowsky

By Paul Cigan, DNR Forest Health Specialist, Hayward;
https://dnr.wisconsin.gov/topic/foresthealth/staff, 715-416-4920

This winter, the spread and impact of emerald ash borer (EAB) have been confirmed in several new northern townships in previously invaded counties.

These include Marengo (Ashland County); Gordon, Hawthorne and Oakland (Douglas County); Cadott and Colburn (Chippewa County) and Balsam Lake and St. Croix Falls (in Polk County).

Continue reading “Emerald Ash Borer Spreads Through The North” →

Feeding Aphids Cause Spruce To Wilt

Posted on by akabelowsky

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

Have you ever wondered just how much sap can be sucked out of a tree by aphids?

Aphids insert their piercing, sucking mouthparts into needles, twigs or bark, depending on the species of aphid.

Once their mouthparts are inserted, they begin to suck sap and will excrete excess moisture as small droplets of water called honeydew.

Continue reading “Feeding Aphids Cause Spruce To Wilt” →

Time for Spongy Moth Treatment Plans

Posted on by akabelowsky

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

A photo showing numerous spongy moth egg masses on a bur oak in Walworth County.

Numerous tan-colored spongy moth egg masses on a bur oak in Walworth County. / Photo Credit: Bill McNee, Wisconsin DNR

The Wisconsin Department of Natural Resources (DNR) encourages property owners to examine their trees for spongy moth egg masses and determine whether control measures are needed this spring.

Spongy moths thrive in warm and dry weather. Even if weather conditions are more typical this spring and summer, the current spongy moth outbreak — which defoliated a state-record total of 373,000 acres of woodland last year — will likely continue and spread.

Continue reading “Time for Spongy Moth Treatment Plans” →

Invasive Species Find The Spotlight In February

Posted on by akabelowsky

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

Graphic showing home page for NISAW.org-slash-forest, titled Invasive Species Are Damaging Our Forests

One focus for policy development during NISAW 2024 is forest health and invasive plants. NAISMA has created an easy way to contact your elected officials to let them know you support the Invasive Species Prevention and Forest Restoration Act. / Image Credit: NAISMA.org

While February in Wisconsin may bring to mind snow-covered ground and little new plant growth, it’s quite a big month for action in the invasive species world. The last week of February brings National Invasive Species Awareness Week (NISAW), an international event that focuses on legislation, policies and funding for the prevention and management of invasive species.

Continue reading “Invasive Species Find The Spotlight In February” →

Squirrel Damage To Maple Trees Showing Up Earlier This Winter

Posted on by akabelowsky

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

Photo of a maple tree with some bark removed by squirrel feeding.

Squirrels have stripped off the bark of this maple tree to get at the sweet cambium layer under the bark. / Photo Credit: Linda Williams, Wisconsin DNR

Typically in the spring, squirrels can cause damage to maple trees by removing bark from branches and the main stem after the trees have been frozen all winter and the weather starts to warm up. This fall, before the January cold spell, temperatures had warmed up by mid-November and remained warm throughout December.

As a result, starting in late November fresh squirrel damage was being noted on some scattered maples in north central Wisconsin. Damage progressed throughout December and some trees have more than half of the bark removed from branches and the main stem. The sight of scattered bits of bark around the base of these trees is another sign of squirrel activity.

Continue reading “Squirrel Damage To Maple Trees Showing Up Earlier This Winter” →

Woodpecker Damage On Ash Trees May Indicate Emerald Ash Borer

Posted on by akabelowsky

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

Photo showing woodpecker damage on an ash tree trunk, an early sign the tree might be infested with emerald ash borer.

Woodpecker damage is an early sign an ash tree might be infested with emerald ash borer. / Photo Credit: Wisconsin DNR

The Wisconsin Department of Natural Resources (DNR) encourages property owners to watch for woodpecker damage to their ash trees this winter. If damage is found, property owners should make plans to take action in the spring.

Woodpecker damage, often called “flecking,” happens when birds peck away some of a tree’s bark to access the larvae underneath. Flecking is a common early sign that an ash tree might be infested with emerald ash borer (EAB), an invasive insect. EAB is the most damaging threat to Wisconsin trees, killing more than 99% of the untreated ash trees it infests.

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Leafminer Creates Green Bay Packers Colors On Aspen Leaves

Posted on by akabelowsky
Photo of an aspen leaf that fell in the fall showing a “green island” due to leafminer feeding.

An aspen leaf that fell in the fall showing a “green island” due to leafminer feeding. / Photo Credit: Linda Williams, Wisconsin DNR

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

Most aspen leaves that fell this fall were a beautiful yellow gold color, but every so often some could be found that were yellow with a green strip on them. Were the aspen trees supporting the Green Bay Packers? No. The green stripe was an indication of the presence of a tiny leafmining caterpillar.

Leafminers are tiny caterpillars that live and feed within a leaf. These tiny caterpillars may produce blotch mines or serpentine mines that create lines on the leaf.

Continue reading “Leafminer Creates Green Bay Packers Colors On Aspen Leaves” →

Forest Health Forecast For 2024

Posted on by akabelowsky

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

An aerial photo of oak and aspen forests showing heavy defoliation from spongy moth.

Oak and aspen forests with heavy defoliation from spongy moth. Additional defoliation coupled with ongoing drought in the upcoming 2024 growing season is expected to put significant stress on affected forests. / Photo Credit: Paul Cigan, Wisconsin DNR

Maintaining a healthy and productive forest often requires — more than ever before — a working knowledge of how to anticipate, prevent and mitigate environmental stressors that threaten to undermine it. The list of stressors includes drought, impact of forest insects and diseases.

In a recent and timely article, Denise Thornton of My Wisconsin Woods taps the expansive knowledge of the DNR’s Forest Health team and a state climatologist to bring focus to the threats facing forests this year.

She also lists steps that can be taken to ensure health and proactivity are maintained in your forests.

Bronze Birch Borer Attacks Stressed Birch

Posted on by akabelowsky

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

Photo of a white birch tree with its top half dying from bronze birch borer attack.

Bronze birch borer has attacked these trees, and parts of the tree above the attack site are thin and declining. / Photo Credit: Linda Williams, Wisconsin DNR

Bronze birch borer (Agrilus anxius) is a native beetle that attacks birch trees. As adults emerge from the bark, they create small, D-shaped exit holes, similar to emerald ash borer but smaller.

Bronze birch borer attacks stressed trees, and the source of the stress can be anything from drought, flooding, defoliation or old age.

Continue reading “Bronze Birch Borer Attacks Stressed Birch” →