Eastern spruce dwarf mistletoe (Arceuthobium pusillum), is a parasitic flowering plant that can be very damaging to black spruce, although it can also attack other spruces. Occasionally you’ll see it on other species growing amidst spruce such as tamarack, white pine, red pine, jack pine, or balsam fir. Continue reading “Eastern spruce dwarf mistletoe”
Disease
Leaf and needle diseases
Many areas of Wisconsin have had abundant rainfall and prolonged cool temperatures this spring which often leads to leaf and needle diseases. The fungal leaf disease anthracnose is the most common issue we see on hardwoods. Continue reading “Leaf and needle diseases”
Frothy foam on pine stems could be stemflow mixing or alcoholic flux
Recently, there were two reports of a white, frothy substance on the bases of otherwise healthy- looking, mature pine. There are two different possible explanations for this interesting and unusual phenomenon. Continue reading “Frothy foam on pine stems could be stemflow mixing or alcoholic flux”
Invasive insects and disease awareness month

Vin Vasive is the spokesman for invasive insects at USDA APHIS. He is made up of invasive species. This USDA APHIS poster was designed by Deb Levy Creative.
April is invasive plant pest and disease awareness month, and May 21-27 is EAB awareness week.
It’s spring, and a good time to remember that invasive species can be easily moved long distances by unsuspecting citizens; maybe even you! All it takes to potentially start a new infestation is to move things we often like to take with us, but don’t know are a problem:
- firewood,
- infected or infested plant material,
- an infected or infested piece of fruit, or
- even a decorative piece of northwoods style furniture that hasn’t been properly treated to kill pests hiding inside.
Take a moment to think about whether you are unknowingly moving items that could harbor pests. The Hungry Pests website lists things you can do to prevent the spread of invasive species, whether you’re a birdwatcher, gardener, hunter, logger, or anyone. Check it out! While you’re there check out some short videos of their “spokesman” Vin Vasive, who has gotten much creepier over the years.
Help spread the word
Coming up, May 21-27 is emerald ash borer awareness week, which is right before the Memorial Day holiday, when lots of travelling, camping, and opening up of summer cabins occurs. The Don’t Move Firewood website has a nice video of how to identify an EAB infested tree. More detailed videos are also available at dnr.wi.gov, keyword “forest health.” If you would like some examples of outreach tools or publications you can use to promote EAB awareness, check out the Don’t Move Firewood website; there you’ll find games for kids, an EAB craft project, videos, press releases, and news articles from past years.
Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172. Categories: FH, UF. Tags: Statewide FH, Insect, Pest
Oak wilt found in Price County, plus prevention steps

Map of the known distribution of oak wilt in Wisconsin as of December 1, 2016.
Oak wilt, a deadly fungal disease affecting red oaks, was confirmed for the first time in Price County in 2016. In addition to the new county find, the disease was also confirmed in various townships in northern Wisconsin counties where we already knew oak wilt was present.
The map in the oak harvesting guidelines was updated based on the find.
Oak wilt is commonly found in the southern two-thirds of the state, but has been creeping northward. The disease was found for the first time in 2010 in Oneida County, in 2012 in Lincoln, Sawyer, and Vilas counties, in 2013 in Rusk County, and in 2014 in Washburn County. Oak wilt has been confirmed in all Wisconsin counties except Ashland, Bayfield, Calumet, Door, Douglas, Forest, Iron, Kewaunee, Manitowoc, Sheboygan, and Taylor.
Read more about oak wilt prevention in the news release from March 21, 2017: Protect oak trees from oak wilt by waiting until after July to prune.
Written by: Kyoko Scanlon, forest pathologist, Fitchburg (Kyoko.Scanlon@Wisconsin.gov), 608-275-3275.
Financial assistance is available for controlling invasive species.
Looking for a financial assist in your efforts to control invasive species?
The Wisconsin Invasive Species Council website lists 61 different grant opportunities that are available from Federal and State agencies as well as private foundations. The list is searchable by applicant (tribe, government agency, company, non-profit, individual) and type of invasive organism (plant, animal, aquatic, invertebrate, disease). All but one has a link that takes you to more information or a contact person.
Why not take a few moments to explore these opportunities?
Written by: Michael Putnam, invasive plants program specialist, Madison (Michael.Putnam@wisconsin.gov), 608-266-7596.
Stump treatment to prevent heterobasidion root disease (Annosum)

Applying a preventative treatment to a fresh pine stump using a backpack sprayer. Photo by: Linda Williams, WI DNR.
There are currently two products available to treat fresh pine stumps to prevent new infections of heterobasidion root disease (HRD), which was previously called annosum. The products are Cellu-Treat and Rotstop-C. Both are water soluble and can be sprayed on the stump. Sporax, a granular/powder product, was previously available but is no longer being manufactured. If you still have a supply of Sporax you can continue to use it. The one-page factsheet on HRD (Annosum) has been updated with information on where to purchase the available products.
For more information on Cellu-Treat and Rotstop-C please check out these websites:
Written by: Kyoko Scanlon, forest pathologist, Fitchburg (Kyoko.Scanlon@Wisconsin.gov), 608-275-3275.
Bur oak blight confirmed in Clark and Sawyer counties in 2016
Bur oak blight (BOB) was confirmed for the first time in Clark and Sawyer counties in 2016. The number of reports of symptoms of this disease was low in 2016 across its range in Wisconsin. Currently, BOB has been detected in 24 counties in Wisconsin.
Continue reading “Bur oak blight confirmed in Clark and Sawyer counties in 2016”
EAB detection continues to grow in urban areas
EAB is an invasive pest that continues to expand and affect more communities in Wisconsin. EAB affects ash trees, which are prevalent in Wisconsin’s urban forests. Communities have been, and continue to create plans to mitigate EAB infestation. Currently, there are 268 communities with known EAB detections. Unfortunately, Wisconsin has far surpassed the former record for most municipal detections in a single year, 86 this year versus 52 in 2015. Continue reading “EAB detection continues to grow in urban areas”