If you’ve noticed large yellow wasps flying around this summer, you may be wondering whether you’ve seen the Asian giant hornet (aka “murder hornet”). This probably gave you some pause considering all the headlines they received earlier this year, but fortunately for Wisconsin and much of the Midwest, murder hornets have not yet been found in the region.
The cicada killer is a common native insect in the Midwest.
By Elly Voigt, forest health lab assistant, Fitchburg
Beech leaf disease (BLD) is a relatively recently discovered, destructive disease of beech trees in the US. It was first observed in 2012 in Ohio and has since spread to areas of Pennsylvania, New York, Connecticut, Rhode Island, Massachusetts and Ontario, Canada. BLD affects our native beech species, American beech (Fagus grandifolia) and ornamental beech species, including European beech (Fagus sylvatica). The disease has not yet been observed in Wisconsin but could become an issue in the future.
Symptomatic leaf puckering of a beech tree with BLD. Credit: Ohio State University.
By Bill McNee, forest health specialist, Oshkosh, Bill.Mcnee@wisconsin.gov, 920-360-0942
Increasing reports of gypsy moth, forest tent caterpillar and other defoliators this summer may indicate rising populations and increased defoliation over the next few years. A recently revised guide to aerial sprays for landowners is now available.
Continue reading “Revised aerial spray guide now available”
The HRD stump treatment guidelines are now available in an interactive format to make it easier to obtain stand-specific recommendations. You can find the link called “Interactive guidelines” on the right side bar under “Additional Resources” at the DNR HRD webpage. The user will be asked a series of questions and then a stand-specific recommendation will be provided at the end. The interactive guidelines incorporate Exceptions and Modifications described in the guidelines. Check it out!
By Todd Lanigan, forest health specialist, Eau Claire, Todd.Lanigan@wisconsin.gov, 715-210-0150
Fall webworm started showing up in early July. This native insect feeds on deciduous trees and shrubs and appears every year in yards and forests. It is often noticed first by the loose webbing over branch tips. It can even completely cover a small tree with webbing. If you look inside the webbing, you will find partially eaten leaves, frass (caterpillar poop) and both live and dead caterpillars.
Fall webworm larvae feed within webbed enclosures at branch tips. Credit: Courtney Celley, US Fish & Wildlife Service.
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”
Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
In early June we started getting reports of balsam fir trees rapidly changing from green to rusty red and dying in just a matter of weeks. Reports and observations are still coming in at the time of this writing, so this article gives a brief synopsis of what we’ve seen so far this year. Symptoms have been observed in some northern and central counties.
Some balsam fir crowns died rapidly this spring for reasons still being explored.
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.
Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
Forest tent caterpillar (FTC) is a native insect with periodic outbreaks. Reports of high populations have been coming in this spring from the towns of Nokomis, Three Lakes and Sugar Camp in Oneida County. There is some defoliation in these areas, but the geographic extent of damage is still limited. When looking for caterpillars in northeastern Wisconsin, it was not difficult to find at least one or two of them, which is an increase from past years when it was difficult to find any caterpillars at all.
Forest tent caterpillars go through several instars, or growth stages. Colors vary between stages but all have the cream-colored “boot prints” down their backs.
Continue reading “Forest tent caterpillar populations high in small localized areas”
Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
Have you noticed any oaks looking kind of red this spring? Or maybe you’ve noticed that the leaves at the tips of the branches are looking red or maroon?
From a distance some oaks have a red hue, probably due to a prolonged and cool spring.
Continue reading “Reddish oak leaves not a cause for concern”
