Forest Health News

Basswood leaves defoliated and trees looking thin

Posted on by margueriterapp

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

Basswood trees in Forest, Marinette and Oconto counties are looking very poor this year. The leaves are damaged, misshapen or completely missing. Several things seem to be happening, but the worst offenders seem to be a late frost/freeze and a suspected infestation by introduced basswood thrips.

Evidence of basswood thrips on a single leaf; some defoliation and dieback.

Evidence of suspected basswood thrips infestation in early spring.

Continue reading “Basswood leaves defoliated and trees looking thin” →

Updated emerald ash borer silviculture guidelines now available

Posted on by margueriterapp

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

Posted on by margueriterapp

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!’

Posted on by margueriterapp

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.

Continue reading “The Tick App! ‘Your Tick Expert On-The-Go!’” →

Native caterpillars not a major concern for trees

Posted on by margueriterapp

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.

Continue reading “Native caterpillars not a major concern for trees” →

Larch casebearer and eastern larch beetle: two problems for tamarack

Posted on by margueriterapp

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.

Continue reading “Larch casebearer and eastern larch beetle: two problems for tamarack” →

All about earthworms: nightcrawler edition

Posted on by margueriterapp

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.

Continue reading “All about earthworms: nightcrawler edition” →

What’s that orange goo?!

Posted on by margueriterapp

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

What’s the orange goo on that tree?!

Should I fight or should I flee?

I bet forest health staff can ID!

Close-up of orange gelatinous gall growing on cedar caused by cedar apple rust.

The spore-producing, slimy, orange gall caused by cedar apple rust fungus.

Continue reading “What’s that orange goo?!” →

Spruce budworm defoliation showing up

Posted on by margueriterapp

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

Spruce budworm defoliation is becoming noticeable in northern and central Wisconsin counties as clipped host tree foliage stuck in the caterpillars’ webbing turns rusty red. The caterpillars should pupate soon, and moths will emerge a couple weeks later to mate and lay eggs. Spruce budworm is a native insect with periodic outbreaks that defoliates spruce and balsam fir in the Midwest.

Close-up of spruce budworm caterpillar near the silk web it spins around branch tips.

Spruce budworm caterpillar near the silk webbing it spins on branch tips.

Continue reading “Spruce budworm defoliation showing up” →

Pine tortoise scale can cause branch and tree mortality, sooty mold problems

Posted on by margueriterapp

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

Pine tortoise scales are sometimes found at very heavy densities on jack and scotch pine twigs. In Wisconsin they prefer young jack pine trees, inserting their straw-like mouthparts into twigs and sucking out the sap. When populations are high, pine tortoise scale can cause branch mortality and even whole tree decline.

Tiny pine tortoise scales clustered on a pine branch tip.

Pine tortoise scales are so plentiful on this twig that they are practically on top of one another.

Continue reading “Pine tortoise scale can cause branch and tree mortality, sooty mold problems” →