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”
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.
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
Basswood trees in Forest, Marinette and Oconto counties are looking very poor this year. The leaves are damaged, misshapen or completely missing. Several things seem to be happening, but the worst offenders seem to be a late frost/freeze and a suspected infestation by introduced basswood thrips.
Evidence of suspected basswood thrips infestation in early spring.
Continue reading “Basswood leaves defoliated and trees looking thin”
By Bill McNee, forest health specialist, Oshkosh, bill.mcnee@wisconsin.gov, 920-360-0942
The Division of Forestry has completed a revision of the emerald ash borer silviculture guidelines to help foresters prepare for and respond to the arrival of emerald ash borer (EAB) in a forest stand.
Continue reading “Updated emerald ash borer silviculture guidelines now available”
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 Bieneke Bron, Midwest Center of Excellence for Vector-Borne Diseases, UW-Madison
Do you ever wonder why you are always finding ticks on yourself or around you, but your friends never do? Researchers at the University of Wisconsin – Madison have developed a mobile application that allows users to share their experiences with ticks to help prevent future tick bites.
Continue reading “The Tick App! ‘Your Tick Expert On-The-Go!’”
Mike Hillstrom, forest health specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov, 608-513-7690
Eastern tent caterpillars (ETC) are hatching and beginning to feed on host trees in Wisconsin, including cherry, apple and crabapple trees. Landowners and homeowners may notice the white silken tents forming in branch forks. Although the tents are unsightly, ETC is a native insect and rarely causes damage. Even completely defoliated trees will put out new leaves within a few weeks.
Eastern tent caterpillars preparing for a day of feeding on a black cherry tree.
Continue reading “Native caterpillars not a major concern for trees”
By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
Tamarack trees are sending out their needles this spring, and larch casebearer caterpillars are feeding on them. In northern Wisconsin, where the trees didn’t push needles out until the end of May, the caterpillars were impatiently waiting to begin feeding and in some counties the damage is now severe.
Tamarack trees defoliated by larch casebearer will appear straw-colored or tan from a distance. Photo taken May 28 in Oneida County.
Continue reading “Larch casebearer and eastern larch beetle: two problems for tamarack”
By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665
Spruce budworm defoliation is becoming noticeable in northern and central Wisconsin counties as clipped host tree foliage stuck in the caterpillars’ webbing turns rusty red. The caterpillars should pupate soon, and moths will emerge a couple weeks later to mate and lay eggs. Spruce budworm is a native insect with periodic outbreaks that defoliates spruce and balsam fir in the Midwest.
Spruce budworm caterpillar near the silk webbing it spins on branch tips.
