Forest Health News

Avoid Ash Trees When Placing Deer Stands

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

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Check Conifer Trees For Severe Root Disease

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

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

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

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

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Red Oak Irony

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.

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Eyes On Beech Leaf Disease

By Ethan Wachendorf, Forest Health Lab Technician, Fitchburg, ethan.wachendorf@wisconsin.gov or 608-273-6276

Forest owners and land managers should be on the lookout for beech leaf disease (BLD), a destructive disease of beech trees. The disease is primarily found on American beech (Fagus grandifolia) but can also be found on ornamental species like European, Oriental and Chinese beech (F. sylvatica, F. orientalis and F. engleriana).

Multiple symptomatic beech leaves showing dark striping between lateral veins on the underside of the canopy.

Symptomatic striping seen from under the canopy. This photo was taken in Ohio. Photo: Wisconsin DNR

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Pine Sawyer Beetle: A Noteworthy Native

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

This time of year, you may see black beetles with long antennae flying around, especially in areas with pine trees. These slow, ungainly flyers are a native longhorn species called white-spotted sawyer beetle, also known as pine sawyer.

Pine sawyers are black beetles with long antennae.

Pine sawyer adult male. Photo: Wisconsin DNR

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Troubled White Pines: Disease And Thinning

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

Scattered white pine in Oneida and Vilas counties had significant amounts of needles that turned light tan or pale yellow this spring. Those needles have mostly dropped from trees, leaving them quite thin.

Some white pine needles are tan colored due to Lophodermium infection.

Tan-colored needles infected with Lophodermium. Photo: Wisconsin DNR

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