Red pine damaged by the April 2nd, 2026, ice storm in central Wisconsin. / Photo Credit: Wisconsin DNR
By Michael Hillstrom, DNR Invasive Forest Pest Coordinator, Fitchburg
Michael.Hillstrom@wisconsin.gov or 608-513-7690
Spring 2026 has seen a variety of tree stress events. Wisconsin trees have experienced snow and ice damage, severe storms that resulted in wind, hail and flood damage and swings in temperatures that brought leaf out and subsequent frost damage.
The 2025 winners of the Invasive Species Action Awards. / Photo Credit: Wisconsin DNR
By Mackenzie Manicki, DNR Invasive Plant Specialist, Madison
In Wisconsin, June is Invasive Species Action Month (ISAM), and plenty of activities are planned to educate and motivate residents and visitors into action.
Invasive species are defined as nonnative organisms whose introduction can cause harm to the environment, the economy, or pose threats to human health.
Continue reading “Invasive Species Action Month: Action Awards, Awareness Weekend”
By Carter Hellenbrand, DNR Invasive Plant Field Specialist, Fitchburg
Carter.Hellenbrand@Wisconsin.gov
Note: This is the second installment in the Forest Health News “Invasives Spotlight” series, a monthly series of Forest Health News articles.
Monarch butterflies are dependent on native milkweed for survival. But did you know there are invasive plants within the milkweed family that negatively impact this relationship?
Continue reading “Invasives Spotlight: Black and Pale Swallow-wort”
By Wisconsin DNR
With 145 invasive plants regulated under Wisconsin’s Invasive Species Rule NR40, it can be challenging to identify some of these plants while out in the woods.
The task can be further complicated by the presence of native lookalikes — plants that have a similar appearance to harmful invasive species, but are native plants that benefit wildlife, pollinators and ecosystems in Wisconsin.
Continue reading “Invasives And Imposters: Native Look-Alikes To Know”
Wisconsin DNR Forest Insect Pest Specialist Mike Hillstrom gives a presentation during a New Forester Training session in Marinette County in 2024. / Photo Credit: Bill McNee, Wisconsin DNR
By Art Kabelowsky, DNR Outreach and Communications, Fitchburg Arthur.Kabelowsky@wisconsin.gov or 608-335-0167
Mike Hillstrom, the Wisconsin Department of Natural Resources Invasive Forest Pest Coordinator, will give a public presentation on forest invasive species from 10 a.m. to noon Saturday, June 20, at Lake Kegonsa State Park in Stoughton.
The talk will be part of the informational and educational events sponsored as part of the DNR’s Invasive Species Awareness Weekend.
A bag of Tim-bor Professional, a borate-based chemical that fights Heterobasidion root disease. / Photo Credit: Wisconsin DNR
By Kyoko Scanlon, Forest Pathologist, Fitchburg
Kyoko.Scanlon@wisconsin.gov
People who have been dealing with Heterobasidion Root Disease (HRD) may be familiar with the product name “Cellu-Treat®.” It has been used to treat fresh cut stumps to prevent HRD.
But Cellu-Treat® is not the only chemical available for HRD. Another borate-based chemical, Tim-bor® Professional, can also be used legally for the same purpose in Wisconsin. Both products are manufactured by Nisus Corporation, and their labels are almost identical (Cellu-Treat label, Tim-bor label).
Continue reading “Fungicide For HRD Stump Treatment Available In Smaller Size”
A 3-D printed trap used to collect hemlock woolly adelgid DNA. / Photo Credit: Wisconsin DNR
By Michael Hillstrom, DNR Invasive Forest Pest Coordinator, Fitchburg
Michael.Hillstrom@wisconsin.gov or 608-513-7690
This spring, the Wisconsin Department of Natural Resources (DNR) is collaborating with the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) to set traps to detect the invasive insect hemlock woolly adelgid (Adelges tsugae; HWA).
The project, funded by the Wisconsin Specialty Crop Block Grant Program, calls for traps to be set to detect the invasive insect. No detection of HWA has been made to date in Wisconsin forests. Continue reading “Cooperative Hemlock Woolly Adelgid Trapping Effort Begins”
Japanese honeysuckle climbing up nearby trees. / Photo Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
By Carter Hellenbrand, DNR Invasive Plant Field Specialist, Fitchburg
Carter.Hellenbrand@Wisconsin.gov
Note: This is the first installment in the Forest Health News “Invasives Spotlight” series, a monthly series of Forest Health News articles.
Many people recognize honeysuckle as a fast-spreading invasive shrub that can quickly displace native vegetation. But did you know that some honeysuckles exist as a vine?
Japanese honeysuckle (Lonicera japonica) is an invasive perennial vine that can grow to a length of 80 feet or longer. Birds will often eat and disperse the berries the vine produces, allowing for the creation of new populations.
A self-service firewood point of sale at Mirror Lake State Park in Sauk County. / Photo Credit: Wisconsin DNR
By Art Kabelowsky, DNR Outreach and Communications, Fitchburg
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167
With camping season about to enter full swing, the Wisconsin Department of Natural Resources (DNR) urges campers to think twice before giving invasive species or harmful hitchhikers a ride in their firewood.
Memorial Day marks the unofficial start of summer, and campfires are a Wisconsin summer staple. And campers should know it’s a big help to the state’s trees when they help to prevent the spread of invasive pests by making smart firewood choices.
Large white grub larvae discovered while splitting firewood. The insects are living in a piece of firewood with a lot of decay. / Photo Credit: Wisconsin DNR
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Hermit flower beetles (Osmoderma spp.) are very large scarab beetles, sometimes called leather beetles.
Three Osmoderma species can be found in Wisconsin, though none are common. Adult beetles look big and beefy but are harmless, eating a little pollen, feeding on ripe fruit and sipping nectar and tree sap during their adult life.
Continue reading “Huge White Grubs Found In Firewood, Rotting Logs”
