South Central WI Forest Health

Frost’s Bite: How Do Insects Survive Winter?

Posted on by akabelowsky
An emerald ash borer larva overwinters by curling into a J shape inside a channel in an ash tree in Brookfield in 2019.

An emerald ash borer larva overwinters by curling into a J shape inside a channel in an ash tree in Brookfield in 2019. / Photo Credit: Bill McNee, Wisconsin DNR

By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg

Michael.Hillstrom@wisconsin.gov

As winter’s chill persists, Wisconsin Department of Natural Resources (DNR) Forest Health staff members are often asked how cold it needs to get to kill insects, especially invasives.

The answer varies from species to species, but many insects are well adapted to dealing with freezing winter temperatures. Some, such as monarchs, avoid the issue and migrate south for the winter. Others, such as multicolored Asian ladybeetles, annoy us with their presence in our homes and offices as they try to avoid the cold until spring.

Continue reading “Frost’s Bite: How Do Insects Survive Winter?” →

DNR Recruiting For Two Forest Health Specialists

Posted on by akabelowsky
A Wisconsin map showing zones of coverage for each of the six DNR Forest Health Specialists

A map showing the zones of coverage for each of the six DNR Forest Health Specialists. / Graphic Credit: 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 opened the search for candidates to fill two Forest Health Specialist openings, one in the West Central zone and one in the South Central zone.

The posting can be seen on the WiscJobs website. To be considered, candidates have until the posted deadline of 11:59 p.m. Monday, Jan. 6, 2025, to submit a resume and letter of qualifications.

Continue reading “DNR Recruiting For Two Forest Health Specialists” →

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” →

What’s That Orange Goo?

Posted on by akabelowsky

A slime mold perched on a vine.

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

What’s the orange goo on that tree?

Should I fight, or should I flee?

I bet forest health staff can ID!

Indeed, there are a number of types of orange goo in the woods during spring.

If it’s a lumpy mass of goo on a log, stump or mulch, then it’s probably a slime mold. Slime molds are an amoeba-like group of organisms called myxomycetes. They move very slowly to eat bacteria and organic matter. Slime molds are harmless, so unless it is covering something of value, just leave it be, and it will disappear on its own. Continue reading “What’s That Orange Goo?” →

Phomopsis Galls Found On Northern Red Oak

Posted on by akabelowsky

By Linda Williams, DNR forest health specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665

Photo showing large Phomopsis galls on a tree before it has leafed out in the spring.

It is often easier to spot large Phomopsis galls before leaves come out in the spring.

Phomopsis galls are large woody swellings on the branches or main stem caused by a fungus. Across Wisconsin, Phomopsis galls can grow on hickory, especially bitternut hickory. However, in some areas of Wisconsin, they can occur on northern red oak.

Northern red oaks sometimes have hundreds of Phomopsis galls on the branches, ranging from as small as a tennis ball to as large as a basketball. Continue reading “Phomopsis Galls Found On Northern Red Oak” →

2024 Spongy Moth Spray Plans Announced

Posted on by akabelowsky

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

Photo of an airplane spraying insecticide on trees at Devil's Lake State Park in Sauk County.

An airplane sprays insecticide on trees at Devil’s Lake State Park in Sauk County. / Photo Credit: Wisconsin DNR

The Wisconsin Department of Natural Resources (DNR) has finalized aerial spraying plans for its 2024 Spongy Moth Suppression Program, with maps for the six selected treatment areas available online.

The treatment sites contain high-value trees at six state parks or forests in Columbia, Marinette, Sauk and Walworth counties. A total of 928 acres will be treated with an aerial spray of “Foray” bacterial insecticide containing Bacillus thuringiensis var. kurstaki.

Continue reading “2024 Spongy Moth Spray Plans Announced” →

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.

Continue reading “Woodpecker Damage On Ash Trees May Indicate Emerald Ash Borer” →

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.