Forest Health News

2025 DNR Spongy Moth Spray Plans Announced

Posted on by akabelowsky
Photo showing an airplane spraying pesticide over trees at Devils Lake State Park in Sauk County to help in the control of spongy moth caterpillars.

An airplane sprays pesticide over trees at Devils Lake State Park in Sauk County to help in the control of spongy moth caterpillars. / Photo Credit: Sue Johansen, Wisconsin DNR

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

The Wisconsin Department of Natural Resources (DNR) has finalized aerial spraying plans for its 2025 Spongy Moth Suppression Program, with maps for the five selected treatment areas available online.

The treatment sites are at three state parks in Juneau, Marinette and Sauk counties that are highly valued for their recreational use. A total of 544 acres of trees will be treated with an aerial spray of “Foray” bacterial insecticide containing Bacillus thuringiensis var. kurstaki.

Continue reading “2025 DNR Spongy Moth Spray Plans Announced” →

La Crosse County Added To Spongy Moth Quarantine

Posted on by akabelowsky
A closeup photo of a spongy moth caterpillar consuming a leaf.

A spongy moth caterpillar consumes a leaf. / Photo Credit: Bill McNee, Wisconsin DNR

By Wisconsin Department of Natural Resources (DNR)

La Crosse County has become the latest Wisconsin location to be added to the state and federal spongy moth quarantine, joining most eastern and central Wisconsin counties already considered to be infested by the invasive insect.

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) announced the change on April 1, based on trapping data collected last year.

Continue reading “La Crosse County Added To Spongy Moth Quarantine” →

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.

Continue reading “April Offers Opportunities For Tree Lovers” →

Fight The Bite! Watch For Ticks

Posted on by akabelowsky

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

Ticks are active now, so it’s time to start taking precautions to prevent tick bites and transmission of the diseases they carry. Whenever temperatures at ground level get above 40-42 degrees Fahrenheit, ticks will start to be active.

Continue reading “Fight The Bite! Watch For Ticks” →

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.

Continue reading “Avoid Seedy Hitchhikers This Summer” →

Watch For Oak Decline And Mortality This Summer

Posted on by akabelowsky
Oak decline and mortality at Big Foot Beach State Park in 2024.

Oak decline and mortality at Big Foot Beach State Park in 2024. / Photo Credit: Wisconsin DNR

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

Oak decline and mortality continue to be an issue in Wisconsin, and because of the recent droughts and spongy moth outbreak, we expect these impacts to become more widespread this summer.

Forest decline is the progressive loss of tree and stand vigor and health over several years without obvious evidence of a single causal factor. Typically, trees die in a scattered fashion across a large area over several years. The additional stress from defoliation can result in pockets of heavy oak mortality, particularly on dry, sandy sites and steep, rocky ridges and hills.

Continue reading “Watch For Oak Decline And Mortality This Summer” →

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.

Continue reading “DNR Urges Spring Spongy Moth Treatment Plans” →

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).

Continue reading “Spring Brings Opportunities To Protect Oak Trees” →

Treat Ash Trees Against Emerald Ash Borer This Spring

Posted on by akabelowsky
A photo of an ash tree next to a park trail in Winnebago County showing damage from woodpeckers feeding on EAB larvae beneath the bark.

An ash tree next to a park trail in Winnebago County shows damage from woodpeckers feeding on EAB larvae beneath the bark. / Photo Credit: Bill McNee, Wisconsin DNR

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

Property owners with healthy, valuable ash trees are encouraged to treat them with insecticide this spring to protect against emerald ash borer (EAB).

The invasive pest is currently the most damaging threat to trees in Wisconsin, killing more than 99% of the ash trees it infests.

Continue reading “Treat Ash Trees Against Emerald Ash Borer This Spring” →

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.

Continue reading “Squirrels Can Damage Trees During Late Winter” →