*These training opportunities are provided as an information service only and do not constitute an endorsement from the Wisconsin Department of Natural Resources.
See below for information on the ISA Virtual Event and other upcoming trainings. Continue reading “Upcoming Trainings”
Two photos of the same spot on a tree in Door County, showing Heterobasidion root disease fruiting bodies (left) and the basal wound beneath them (right). / Photo Credits: Bill McNee, Wisconsin DNR
By Bill McNee, DNR Forest Health Specialist, Oshkosh;
Bill.McNee@wisconsin.gov or 920-360-0942
Heterobasidion root disease (HRD), formerly known as annosum root rot, was recently found in Door County for the first time.
In mid-September, several suspected HRD fruiting bodies were spotted in a white spruce plantation on privately owned land in the town of Sevastopol. One cluster of fruiting bodies located at the base of a dead spruce was confirmed as Heterobasidion irregulare, the fungal pathogen that causes HRD. The other fruiting bodies were identified as a native decay fungus that has a similar appearance.
Continue reading “Heterobasidion Root Disease Found In Door County”
By Michael Hillstrom, Forest Health Specialist, Fitchburg
Michael.Hillstrom@wisconsin.gov
Oak decline at Big Foot Beach State Park caused by flooding, drought, spongy moth defoliation, twolined chestnut borer and Armillaria. / Photo Credit: Michael Hillstrom, Wisconsin DNR
Bur and white oaks, most of them more than 100 years old, have experienced rapid mortality (within one to two years) over the past four years in southern Wisconsin and neighboring states. Research into the cause is ongoing, but the evidence so far suggests it’s an oak decline.
Oak declines are not caused by a single issue, but rather by the stacking of multiple health issues. Drought, flooding, storm damage, age, twolined chestnut borer, Armillaria and other root pathogens, and spongy moth and oak leafroller defoliation all play a role in the damage.
Continue reading “Oak Decline Continues In Southern Wisconsin”
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
The acorn farthest on the right has pip galls. Squirrels ate the pip galls from the other acorns. / Photo Credit: Linda Williams, Wisconsin DNR
Several areas in northern Wisconsin have reported significant acorn drop. In almost all cases, these acorns have been damaged by either pip galls or acorn weevils.
Squirrels enjoy feeding on pip galls and will pluck those acorns off the tree, rip off the cap, eat the pip gall and drop the rest of the acorn to the ground. Squirrels will also seek out acorns infested by acorn weevils. They will open those acorns, eat the larvae and then drop the rest of the acorn to the ground.
Continue reading “Squirrels Love Acorn Pip Galls And Weevils”
By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665
Oak leaves that drop from a tree infected with oak wilt may be all brown or all green, or often they will have green near the base of the leaf and the outer portions will be brown or watersoaked green. / Photo Credit: Linda Williams, Wisconsin DNR.
The middle of summer is the time to start watching oak trees for symptoms of oak wilt. Although symptoms show up suddenly and leaves drop quickly, symptoms can emerge anytime between now and when leaves turn color in the fall.
Trees that were wounded in the spring and became infected with the fungus that causes oak wilt will usually die that same year. In established oak wilt pockets, the fungus moves underground through grafted root systems and trees will wilt as the fungus moves into the tree.
By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665
A tree showing that lower branches are thin and have lost leaves due to Tubakia leaf spot, while leaves on its upper branches look good. / Photo Credit: Linda Williams, Wisconsin DNR.
Tubakia leaf spot is a leaf disease caused by a fungus (Tubakia dryina) that typically affects the lower canopy of red oaks.
Because of all the rain that came during the spring and early summer of 2024, the fungus has started to impact some trees. Problems didn’t occur last year because the weather was too dry.
By Kyoko Scanlon, DNR Forest Pathologist, Fitchburg;
Kyoko.Scanlon@wisconsin.gov or 608-235-7532
Forest owners and land managers should look for beech leaf disease (BLD) this summer, a destructive beech tree disease in the United States.
The disease is primarily found on American beech (Fagus grandifolia) but can also be found on ornamental species such as European, Oriental and Chinese beech (F. sylvatica, F. orientalis and F. engleriana). Although it has not yet been found in Wisconsin, recent discoveries of the disease in Michigan and other nearby states highlight the continued importance of monitoring BLD’s expansion. There is potential for BLD to move into Wisconsin as the eastern portion of the state overlaps with the native range of American beech.
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Eastern white pines (Pinus strobus) can be beautiful trees in urban and forested areas (they can tower above the rest of the forest’s trees), but they can also attract a deadly disease.
White pine blister rust (Cronartium ribicola), also known as WPBR, is a fungus that can attack branches and the main stem of white pine, causing cankers that continue to grow each year and creating dead spots that can girdle branches or the main stem. Damage from a girdling canker may take years to become severe enough to cause tree decline and mortality. That means you may be able to help your trees and prevent mortality.
Continue reading “Pruning Can Control White Pine Blister Rust”
A swath of pine dead due to high water table mortality in 2020 in northeast Wisconsin.
By Alex Hornung, DNR Forest Health Specialist, Plover;
Alexandra.Hornung@wisconsin.gov
Many pine stands across central and northeast Wisconsin are being impacted by the change from high levels of precipitation to extreme drought that has occurred over the last 5-7 years.
Drastic or sudden changes can be particularly stressful to trees of all species, but especially to pine stands that prefer well-drained soil types.
A slime mold perched on a vine.
By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg;
Michael.Hillstrom@wisconsin.gov
What’s the orange goo on that tree?
Should I fight, or should I flee?
I bet forest health staff can ID!
Indeed, there are a number of types of orange goo in the woods during spring.
If it’s a lumpy mass of goo on a log, stump or mulch, then it’s probably a slime mold. Slime molds are an amoeba-like group of organisms called myxomycetes. They move very slowly to eat bacteria and organic matter. Slime molds are harmless, so unless it is covering something of value, just leave it be, and it will disappear on its own. Continue reading “What’s That Orange Goo?”
