Woodland owners

Maple Petiole Borer Sawfly Causing Leaf Drop

Posted on by akabelowsky
A closeup display photo showing prematurely fallen sugar maple leaves that have a normal appearance, except for characteristic darkened petiole stubs caused from feeding damage of the maple petiole borer.

Prematurely fallen sugar maple leaves with normal appearance except for characteristic darkened petiole stubs caused from feeding damage of the maple petiole borer. / Photo Credit: Paul Cigan, Wisconsin DNR

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

Fallen maple leaves have been observed under Wisconsin maple trees since late May.

The fallen leaves are typically of normal shape, size and color, but have a darkened petiole stub (i.e., leaf stem) remaining. A closer examination of the petiole may reveal a hollow feeding tunnel containing tiny larvae of the insect responsible for the damage inside: the maple petiole borer.

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DNR Debuts Fact Sheet On White Grubs

Posted on by akabelowsky
Closeup photo showing a white grub in topsoil, feeding on a root.

A white grub feeds on a root. / Robert L. Anderson, USDA Forest Service, Bugwood.org

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

White grubs, the larvae of Wisconsin’s native May/June beetles (Phyllophaga spp.), can cause significant damage to forest plantings.

To help those who plan to plant seedlings and saplings, the Wisconsin Department of Natural Resources’ (DNR) Forest Health team has produced a fact sheet on white grubs, aimed specifically at forest plantings.

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Please Submit Trees Planted This Spring!

Posted on by janness

By Dan Buckler, DNR Urban Forest Assessment Specialist; Daniel.Buckler@wisconsin.gov or 608-445-4578

When your newly planted trees are getting comfortable in their new homes, you’ve pulled the splinters from your hands and you find yourself at a desk asking yourself, “What now?”, we have an answer for you.

Please take a moment and record your trees in the Wisconsin Tree Planting Survey. Those submissions will then appear on the Tree Planting Map and be tallied toward the state’s pledge to the Trillion Trees Initiative. Governor Tony Evers signed the pledge to protect and restore Wisconsin’s rural and urban forests by planting 100 million trees in Wisconsin by 2030. Continue reading “Please Submit Trees Planted This Spring!” →

Rotstop® C No Longer Available In North America

Posted on by akabelowsky
Photo of a worker manually applying fungicide, imbued with blue dye, to a freshly cut tree stump to fight the spread of fungal diseases such as Heterobasidion root disease.

A worker manually applies fungicide, imbued with blue dye, to a freshly cut tree stump to fight the spread of fungal diseases such as Heterobasidion root disease. / Photo Credit: Wisconsin DNR

By Kyoko Scanlon, DNR Forest Pathologist, Fitchburg
Kyoko.Scanlon@wisconsin.gov

The manufacturer, Lallemand Plant Care, recently decided to remove Rotstop® C fungicide from the North American market.

As a result, the product is no longer available for purchase in North America. If you already have the product and have stored it in an appropriate space, you may still use it as a preventative treatment for Heterobasidion root disease (HRD) as long as the expiration date has not arrived.

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April Offers Opportunities For Tree Lovers

Posted on by akabelowsky
Wide-angle photo showing that a beautiful view of Wisconsin forestland awaits visitors to Roche a Cri State Park in Adams County.

A beautiful view of Wisconsin forestland awaits visitors to Roche a Cri State Park in Adams County. / Photo Credit: Wisconsin DNR

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

“Acts of creation are ordinarily reserved for gods and poets. To plant a pine, one need only own a shovel.”

Those were the words of Wisconsin’s most prominent conservation expert, Aldo Leopold, who authored the famous book, “A Sand County Almanac” among his many achievements.

This month, everyone in Wisconsin will have the chance to follow Leopold’s advice – even if in a small way, because many small efforts can add up to a prominent positive impact on Wisconsin’s trees and forests.

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Avoid Seedy Hitchhikers This Summer

Posted on by akabelowsky
A photo showing a large patch of the invasive plant garlic mustard on a wooded property. The aggressive plant spreads and outcompetes native plants and trees for nutrients.

Avoid creating infestations of invasive plants — such as this huge patch of garlic mustard — on your wooded properties; don’t transport or plant aggressive spreaders as you head up north this summer. / Photo Credit: Steven Katovich, Bugwood.org

By Wisconsin Department of Natural Resources (DNR)

Hitchhiking invasive plants, insects and pathogens are worthy of concern.

As you dream of days spent at the cabin up north, planting your garden or wandering in the woods, here are a few reminders to help you avoid bringing hitchhiking invasives along as you enjoy your spring and summer activities.

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DNR Urges Spring Spongy Moth Treatment Plans

Posted on by akabelowsky
Carefully scraping spongy moth egg masses off trees and into a cup of soapy water will help to hold down caterpillar damage in 2025.

Carefully scraping spongy moth egg masses off trees and into a cup of soapy water will help to hold down caterpillar damage in 2025. / Photo Credit: Bill McNee, Wisconsin DNR

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

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.

Property owners who have oak, birch, crabapple, aspen, willow and linden (basswood) trees should be particularly watchful because the caterpillars of this invasive insect prefer these species. However, they will feed on many other kinds of trees and shrubs.

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Spring Brings Opportunities To Protect Oak Trees

Posted on by akabelowsky
A photo of an oak tree with a branch that has been pruned, but not treated with protective paint to prevent infection with oak wilt.

Pruning, cutting, or wounding oaks during April through July leaves them vulnerable to oak wilt. / Photo Credit: Paul Cigan, Wisconsin DNR

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

With warmer spring weather fast approaching, the Wisconsin Department of Natural Resources (DNR) recommends protecting oaks from the often-fatal disease, oak wilt, by refraining from pruning, cutting or injuring oak trees from April through July.

Oak wilt is a serious disease that kills trees in the red oak group (including pin oak, northern red oak and black oak) and weakens those in the white oak group (bur oak, swamp white oak, white oak and English oak).

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Squirrels Can Damage Trees During Late Winter

Posted on by akabelowsky
Photo showing that squirrels have removed significant amounts of bark from a maple tree's trunk to get at the tasty cambium layer underneath.

Squirrels have removed significant amounts of bark from this maple to get at the tasty cambium layer underneath. / Photo Credit: Linda Williams, Wisconsin DNR

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

Squirrels can be fun to feed and fun to watch, but when they start damaging or killing your trees, well, that’s not so cute.

It’s the time of year when we start to have some warm days that allow sap to start moving in trees. If there are broken branches or damaged bark, the tree can drip sap. And that can attract squirrels.

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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” →