The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), in partnership with the Wisconsin DNR, has detected emerald ash borer in four new counties (Dunn, Oconto, Pepin and Shawano). Please read this DATCP article for more information.
Adult emerald ash borer beetle.
If you are a landowner and have questions about ash trees in your woodlot, contact your local DNR forester using the Forestry Assistance Locator.
By Bill McNee, forest health specialist, Oshkosh, firstname.lastname@example.org, 920-360-0942
The summer of 2020 saw a major rebound of the gypsy moth population after several years of weather conditions that were unfavorable for the non-native, defoliating pest. A mild winter and average summer temperatures/precipitation during the caterpillar stage were all favorable for a population increase.
Female moth laying eggs on tree trunk.
Continue reading “Gypsy moth populations rebound in 2020 – look for egg masses this fall”
By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
If you’ve ever looked closely at oak leaves in late summer you know that you can find lots of interesting things on them this time of year. You’ll see anything from a variety of caterpillars and galls of all shapes and sizes to dead portions of branches caused by insects and diseases. These late season defoliators rarely cause actual health issues for the tree, and rarely require any control, but they can be very noticeable with some dramatic damage. Continue reading “Oak webworms, blotchminers, skeletonizers and dead branch tips in late summer”
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.
Continue reading “Wondering about large yellow wasps?”
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.
Continue reading “Be on the lookout for beech leaf disease”
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.
Continue reading “Fall webworm activity in July”
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.
Continue reading “Reports of sudden balsam fir mortality”