Don’t Move Firewood, The Nature Conservancy
October is Firewood Month! Help prevent the spread of invasive insects and diseases by buying firewood where you burn it.
Firewood Scout can help you find local firewood for sale.
See the DNR website for more information on invasive species and forest health. Continue reading “Moving Firewood Can Spread Invasive Species”
By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg, michael.hillstrom@wisconsin.gov
Considered one of the most destructive diseases of conifers in the northern hemisphere, Heterobasidion root disease (HRD) is very difficult to control once established in a forest. Infestation of a conifer stand may significantly impact stand management, making early detection essential.
A Heterobasidion root disease (HRD) fruit body with new white growth observed in the fall. Photo: Wisconsin DNR
Continue reading “Check Conifer Trees For Severe Root Disease”
By Linda Williams, Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665
Northeastern Wisconsin saw thin and defoliated aspen trees in early summer this year due to a few diseases. A sample from Marinette County turned up Alternaria leaf and stem blight, Venturia leaf and shoot blight and Phyllosticta leaf spot. Venturia was also noted in central Wisconsin, causing shoot blight, which kills the terminal leaders (growth buds) of young aspen.
Aspen crowns were thin due to multiple leaf diseases. Photo: Wisconsin DNR
Continue reading “Aspen Leaf Diseases Responsible For Thin Crowns”
By Ethan Wachendorf, Forest Health Lab Technician, Fitchburg, ethan.wachendorf@wisconsin.gov or 608-273-6276
Forest owners and land managers should be on the lookout for beech leaf disease (BLD), a destructive disease of beech trees. The disease is primarily found on American beech (Fagus grandifolia) but can also be found on ornamental species like European, Oriental and Chinese beech (F. sylvatica, F. orientalis and F. engleriana).
Symptomatic striping seen from under the canopy. This photo was taken in Ohio. Photo: Wisconsin DNR
By Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665
Scattered white pine in Oneida and Vilas counties had significant amounts of needles that turned light tan or pale yellow this spring. Those needles have mostly dropped from trees, leaving them quite thin.
Tan-colored needles infected with Lophodermium. Photo: Wisconsin DNR
Continue reading “Troubled White Pines: Disease And Thinning”
By Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665
Tubakia leaf spot (Tubakia dryina) is a leaf disease that typically affects the lower canopy of oaks. It caused some issues in 2021 and is affecting red oak trees in north-central Wisconsin this year as well.
Tubakia creates abnormal blotches and spots on oak leaves that can coalesce. Photo: Wisconsin DNR
By Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665
Lecanium scale is popping up in a few areas of Oneida and Vilas counties. These scale insects insert their mouthparts into twigs and suck the sap of the tree. They release honeydew, which can be collected by ants or may coat leaves and anything located under infested trees (i.e., yard furniture or vehicles). Sooty mold can grow on that sticky material and turn things black, so homeowners may want to rinse off the honeydew from outdoor items on a regular basis.
The brown lumps on this stem are lecanium scales. Photo: Wisconsin DNR
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov, 920-360-0665
Have you ever seen an oak wilt fruiting body? Oak wilt is a fungal disease that kills trees in the red oak group (northern red oak, northern pin oak, black oak and other oaks with points on their leaves). Trees in the white oak group (white oak, burr oak, swamp white oak and other oaks with rounded leaves) are more resistant to the disease, but branches or branch tips can still be killed.
Oak wilt pressure pads can create a crack in the bark, allowing beetles to get into the spores. Photo: Wisconsin DNR
Continue reading “On The Lookout For Oak Wilt Fruiting Bodies”
By Michael Hillstrom, DNR Forest Health Specialist, Fitchburg, michael.hillstrom@wisconsin.gov
Typical browning leaf symptoms of red oak trees infected with oak wilt. Photo: Wisconsin DNR
Now is the time to watch for oak wilt! Symptoms typically appear in southern Wisconsin in late June and in northern Wisconsin during July. Watch for browning leaves starting at the top of the canopy and progressing downward. Most leaves will fall from infected trees as they die, typically within two to four weeks.
Several management methods are available to contain oak wilt pockets, so consult your local forest health specialist for guidance on your best options.
The forest health team is also working to evaluate new control methods. Rapid response is currently being tested to more formally evaluate if a new oak wilt infection in a single tree can be stopped before it reaches the roots and spreads to nearby oaks. There is observational data that this method works, but more formal tests are desired. Continue reading “June To October: Oak Wilt Watch!”
By Ethan Wachendorf, DNR Forest Health Lab Technician, Fitchburg, ethan.wachendorf@wisconsin.gov or 608-273-6276
Have you noticed orange, jelly-like growths on cedars this spring? These growths may look like tiny octopus creatures with legs extending all directions, but they’re actually spore horns caused by a fungus.
Orange jelly-like spore horns caused by cedar-apple rust fungus. Photo: Wisconsin DNR
Continue reading “When It Rains, It Spores! Orange Spore Horns Emerge”
