West Central WI forest health

Fall webworm activity in July

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By Todd Lanigan, forest health specialist, Eau Claire, Todd.Lanigan@wisconsin.gov, 715-210-0150

Fall webworm started showing up in early July. This native insect feeds on deciduous trees and shrubs and appears every year in yards and forests. It is often noticed first by the loose webbing over branch tips. It can even completely cover a small tree with webbing. If you look inside the webbing, you will find partially eaten leaves, frass (caterpillar poop) and both live and dead caterpillars.

Fall webworm caterpillars atop

Fall webworm larvae feed within webbed enclosures at branch tips. Credit: Courtney Celley, US Fish & Wildlife Service.

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Reports of sudden balsam fir mortality

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Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665

In early June we started getting reports of balsam fir trees rapidly changing from green to rusty red and dying in just a matter of weeks. Reports and observations are still coming in at the time of this writing, so this article gives a brief synopsis of what we’ve seen so far this year. Symptoms have been observed in some northern and central counties.

The top half of a balsam fir died rapidly this spring due to reasons we are still exploring.

Some balsam fir crowns died rapidly this spring for reasons still being explored.

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Report surviving elm in the forest

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You can help keep native elm trees in the forests of Wisconsin! The US Forest Service continues to work on a project to identify Dutch elm disease (DED)-tolerant American elms native to Wisconsin forests. The goal of the project is to identify and propagate survivor American elms, especially from the colder hardiness zones 3-4, and develop a series of clone banks. Selections would eventually be screened for tolerance to DED. Ultimately, the goal is to make DED-tolerant American elm available for reforestation in northern areas, particularly as a component on sites currently forested by black ash.

If you live in hardiness zones 3 and 4, please look for evidence of surviving elms and report them to the US Forest Service.

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Reddish oak leaves not a cause for concern

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Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665 

Have you noticed any oaks looking kind of red this spring? Or maybe you’ve noticed that the leaves at the tips of the branches are looking red or maroon? 

Some oak leaves look red from a distance, likely due to a prolonged cool spring.

From a distance some oaks have a red hue, probably due to a prolonged and cool spring.

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Updated emerald ash borer silviculture guidelines now available

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By Bill McNee, forest health specialist, Oshkosh, bill.mcnee@wisconsin.gov, 920-360-0942

The Division of Forestry has completed a revision of the emerald ash borer silviculture guidelines to help foresters prepare for and respond to the arrival of emerald ash borer (EAB) in a forest stand.

Cover page of new guidelines. Continue reading “Updated emerald ash borer silviculture guidelines now available” →

New insect and disease factsheets available

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By Mike Hillstrom, forest health specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov, 608-513-7690

The forest health team has produced four new factsheets since the start of 2020. These resources are designed to be informative, 2-page documents for a wide audience that includes landowners, foresters and natural resource professionals, educators, and more. The new factsheets of 2020 are linked below, and more will be announced as they are finalized:

Please check them out and our other recently updated factsheets about Heterobasidion root disease, oak wilt, conifer bark beetles, and hickory decline and mortality. You can find all of these and more forest health publications in the publications catalogue and on the DNR forest health webpage.

The Tick App! ‘Your Tick Expert On-The-Go!’

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By Bieneke Bron, Midwest Center of Excellence for Vector-Borne Diseases, UW-Madison

Do you ever wonder why you are always finding ticks on yourself or around you, but your friends never do? Researchers at the University of Wisconsin – Madison have developed a mobile application that allows users to share their experiences with ticks to help prevent future tick bites.

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Native caterpillars not a major concern for trees

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Mike Hillstrom, forest health specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov, 608-513-7690

Eastern tent caterpillars (ETC) are hatching and beginning to feed on host trees in Wisconsin, including cherry, apple and crabapple trees. Landowners and homeowners may notice the white silken tents forming in branch forks. Although the tents are unsightly, ETC is a native insect and rarely causes damage. Even completely defoliated trees will put out new leaves within a few weeks.

A cluster of eastern tent caterpillars on white silk tent.

Eastern tent caterpillars preparing for a day of feeding on a black cherry tree.

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Larch casebearer and eastern larch beetle: two problems for tamarack

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

Tamarack trees are sending out their needles this spring, and larch casebearer caterpillars are feeding on them. In northern Wisconsin, where the trees didn’t push needles out until the end of May, the caterpillars were impatiently waiting to begin feeding and in some counties the damage is now severe. 

A horizon of tamarack trees defoliated by larch casebearer appear straw-colored or tan from a distance.

Tamarack trees defoliated by larch casebearer will appear straw-colored or tan from a distance. Photo taken May 28 in Oneida County.

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All about earthworms: nightcrawler edition

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By Bernie Williams, invasive plants and earthworms specialist, Madison, Bernadette.Williams@wisconsin.gov, 608-444-6948

As the weather warms up and more of us are out in our gardens digging around, it seems like a good time to learn a few things about those fascinating and beautiful worms you keep encountering.

Close-up of nightcrawler shows its reddish-pink body in detail.

Nightcrawlers have reddish-pink bodies and can be 6-8 inches long when mature.

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