Forest Health News

Twolined Chestnut Borer Attacks On The Rise

Posted on by brenna.denamur

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

Twolined chestnut borer (TLCB) attacks on oak trees have increased in numerous Wisconsin counties, with decline and associated mortality in the last two growing seasons, most noticeably since August.

Symptoms of infestation by this native beetle are initially seen in mid-July on the outer portions of branches in the upper crown. Leaves begin to fade from green to yellow to red. Within a matter of weeks, they turn brown and remain on the branches for weeks to months. Their foliage may also appear sparse or completely bare (Fig. 1).

Trees with twolined chestnut borer symptoms

Figure 1. Northern red oaks with symptoms of twolined chestnut borer, ranging from crown thinning and leaf chlorosis like the tree on the left (early stage) to dead top branches like the tree on the right (intermediate stage). Photo: Wisconsin DNR

Continue reading “Twolined Chestnut Borer Attacks On The Rise” →

Moving Firewood Can Spread Invasive Species

Posted on by brenna.denamur
An image of an insect walking away from burning firewood in a forest with the caption, “Buy it where you burn it.”

Don’t Move Firewood, The Nature Conservancy

October is Firewood Month! Help prevent the spread of invasive insects and diseases by buying firewood where you burn it.

Firewood Scout can help you find local firewood for sale.

See the DNR website for more information on invasive species and forest health. Continue reading “Moving Firewood Can Spread Invasive Species” →

Bernie Williams Retirement

Posted on by brenna.denamur
Bernie Williams

Bernie Williams was the Forest Health Team’s worm specialist.

By Becky Gray, DNR Forest Health Team Leader, Fitchburg, Rebecca.Gray@wisconsin.gov or 608-220-3022

While Bernie Williams might yet become a famous artist or comedian, her work with the DNR Forest Health Program was retired on Aug. 29, 2022. Bernie reached minor celebrity status through her presentations on invasive plants and worms across Wisconsin and the country. She was awarded for Outstanding Contribution to Accomplishing the Division of Forestry’s Purpose in 2018 because of her role with the Best Management Practices (BMPs) for Invasive Species, NR40 and her dedication to outreach and education. We are really going to miss Bernie’s humor and crazy stories and wish her all the best as she takes her garden, bees and travels to the next level!

For invasive plant questions, please contact Mary Bartkowiak or Jaqi Christopher. For worm questions, please contact Scott Schumacher.

Avoid Ash Trees When Placing Deer Stands

Posted on by brenna.denamur

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

The Wisconsin Department of Natural Resources (DNR) cautions hunters to avoid placing deer stands in or near ash trees this deer season as they start scouting properties.

Hunter in trees

It is important to place and maintain tree stands carefully as you prepare for this upcoming hunting season. Photo Credit: Wisconsin DNR

Continue reading “Avoid Ash Trees When Placing Deer Stands” →

Check Conifer Trees For Severe Root Disease

Posted on by brenna.denamur

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

Considered one of the most destructive diseases of conifers in the northern hemisphere, Heterobasidion root disease (HRD) is very difficult to control once established in a forest. Infestation of a conifer stand may significantly impact stand management, making early detection essential.

A pine stump with a Heterobasidion root disease fruit body with old brown growth in the center and new, bright white growth along the edges.

A Heterobasidion root disease (HRD) fruit body with new white growth observed in the fall. Photo: Wisconsin DNR

Continue reading “Check Conifer Trees For Severe Root Disease” →

Look For Spongy Moth Egg Masses – Larger Outbreak Possible in 2023

Posted on by kirsten.biefeld

By: Bill McNee, DNR Forest Health Specialist, Oshkosh

bill.mcnee@wisconsin.gov or 920-360-0942

Three tan-colored spongy moth egg masses on a single tree branch in Walworth County.

Three spongy moth egg masses on a branch in Walworth County. Photo Credit: Bill McNee, Wisconsin DNR

Now that spongy moth* (formerly known as gypsy moth) egg laying is complete for 2022, it’s a good time to look for and dispose of egg masses produced by adult moths over the past two months.

Spongy moth egg masses are tan-colored lumps about the size of a nickel or quarter, and are found on trees, buildings and other outdoor objects. They may also be found in protected places such as firewood piles and birdhouses. Newly produced egg masses will feel firm and appear darker in color than older egg masses, which appear faded, feel spongy and do not contain viable eggs. The current-year egg masses will not hatch until next spring.

In 2022, Wisconsin’s spongy moth population grew for a third consecutive summer due to favorable weather conditions and limited caterpillar mortality from diseases. The outbreak was most dramatic in opposite ends of the state. In southern and southeast Wisconsin, several thousand oak-dominated acres were heavily defoliated and very large numbers of property owner reports were received by DNR staff. In Bayfield County, about 80,000 acres of rural defoliation was reported from aspen-dominated forests. Smaller patches of defoliation were also reported from several other counties. Continue reading “Look For Spongy Moth Egg Masses – Larger Outbreak Possible in 2023” →

Aspen Leaf Diseases Responsible For Thin Crowns

Posted on by brenna.denamur

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

Northeastern Wisconsin saw thin and defoliated aspen trees in early summer this year due to a few diseases. A sample from Marinette County turned up Alternaria leaf and stem blight, Venturia leaf and shoot blight and Phyllosticta leaf spot. Venturia was also noted in central Wisconsin, causing shoot blight, which kills the terminal leaders (growth buds) of young aspen.

Aspen trees with leaves damaged by leaf disease..

Aspen crowns were thin due to multiple leaf diseases. Photo: Wisconsin DNR

Continue reading “Aspen Leaf Diseases Responsible For Thin Crowns” →

Red Oak Irony

Posted on by brenna.denamur

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

Red oak trees in many areas of northern Wisconsin are aptly fitting their name as many crowns exhibit a red hue this summer.

A red oak tree with a red and green leaves.

Red oaks are producing a second flush of leaves following oak leafroller defoliation in spring, resulting in trees with red-looking crowns. Photo: Wisconsin DNR

Widespread defoliation by oak leafrollers in May and June has led many oaks to generate a second set of leaves after being stripped. New expanding leaves often display a prominent red color that gives the tree crown a stark reddish appearance from afar.

Continue reading “Red Oak Irony” →