Mike Hillstrom, forest health specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov, 608-513-7690
Chlorosis, which is marked by yellow leaves with green veins, is a common tree and shrub issue in Wisconsin. It is often a result of a nutrient deficiency of iron and manganese.
A chlorotic oak leaf displays yellow leaf tissue with green veins.
Continue reading “Chlorosis: common causes and next steps in management”
You can help keep native elm trees in the forests of Wisconsin! The US Forest Service continues to work on a project to identify Dutch elm disease (DED)-tolerant American elms native to Wisconsin forests. The goal of the project is to identify and propagate survivor American elms, especially from the colder hardiness zones 3-4, and develop a series of clone banks. Selections would eventually be screened for tolerance to DED. Ultimately, the goal is to make DED-tolerant American elm available for reforestation in northern areas, particularly as a component on sites currently forested by black ash.
If you live in hardiness zones 3 and 4, please look for evidence of surviving elms and report them to the US Forest Service.
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.
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!
The spore-producing, slimy, orange gall caused by cedar apple rust fungus.
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.
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”
The University of Wisconsin Plant Disease Diagnostics Clinic (PDDC) has started to accept a limited number of physical samples. However, clinic staffing and hours will be limited, and the number of samples that the clinic will be able to accommodate will be severely restricted. Prioritization of the samples currently goes to:
Continue reading “Plant disease diagnostics in the time of COVID-19”
The UW-Madison Plant Disease Diagnostics Clinic (PDDC) provides expertise in diagnosing plant diseases, and information on plant diseases and their control to agricultural and horticultural producers and businesses, as well as home gardeners, throughout the state of Wisconsin.
If you are interested in receiving regular updates on the educational materials and programs provided by the PDDC, please email Brian Hudelson at pddc@wisc.edu to have your email address added to the new clinic listserv, “UWPDDCLearn”. This listserv will provide announcements of when new content is posted to the PDDC website (https://pddc.wisc.edu/), including (but not limited to) new and revised University of Wisconsin Garden Facts/Farm Facts/Pest Alerts fact sheets, the Wisconsin Disease Almanac (a weekly summary of diagnoses made at the PDDC) and monthly clinic web articles. The listserv will also provide announcements about upcoming PDDC outreach programs.
Continue reading “New UW-Madison Plant Disease Diagnostics Clinic listserv”
By Kyoko Scanlon, forest pathologist, Kyoko.Scanlon@wisconsin.gov, 608-235-7532
The Wisconsin DNR recently created a short video on Heterobasidion root disease (HRD) to compliment the updated guidelines that were released in 2019. The 5-minute educational video covers HRD biology, its significance as a tree disease, signs and symptoms, as well as preventative measures that landowners can take to reduce its introduction and spread. This is a great video for forestry professionals, landowners and the general public to learn more about HRD. Continue reading “Educational HRD video now available”
By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
White pine branches that suddenly turn red may be a sign of white pine blister rust. White pine blister rust is a fungal infection that creates expanding “dead spots” or cankers on the branches or main stem of host trees. Eventually the fungus grows enough to girdle the branch or main stem and the needles fade from green to pale green to rusty red. Orange, spore-producing pustules erupt around the edges of the canker in the spring.
Orange pustules erupt through the bark and around the margins of a white pine blister rust canker. Photo by Jean Romback-Bartels.
Continue reading “White pine blister rust can girdle branches”
By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
There are three things you may find interesting about gall rusts on jack pine at this time of year. The first is that as winter recedes, closer examination of the galls on jack pine shows that squirrels like to chew on them. The squirrels seem to prefer the smaller galls, with most chewing marks being observed on galls less than 2” in diameter. They eat the galls by scraping off the outer layers, leaving behind telltale teeth marks.
Squirrels sometimes feed on galls, scraping away the outer layers and leaving teeth marks behind.
