Art Kabelowsky, DNR Forest Health outreach and communications specialist
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167
Add “YouTube Influencer” to the long list of career accomplishments of Andrea Diss-Torrance, Ph.D.
With the spongy moth caterpillar population on the rise in many areas of Wisconsin this season, the Wisconsin Department of Natural Resources stepped into action last month.
Art Kabelowsky, DNR Forest Health outreach and communications specialist
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167
The statewide quarantine for emerald ash borer will end July 1, as one of several permanent rule changes proposed by the Wisconsin Department of Agriculture, Trade and Consumer Protection.
Changes are coming to some of Wisconsin’s rules for plant inspection and plant control, following legislative approval of a proposal from the Department of Agriculture, Trade and Consumer Protection (DATCP).
The rule changes for ATCP 21 (Clearinghouse Rule CR 22-022), in the works since 2020, will go into effect on July 1.
One of the permanent rule changes involves the end of the state quarantine for emerald ash borer. Other quarantines to be rescinded are those for pine shoot beetle and thousand cankers disease of walnut trees.
The changes were recommended by DATCP for one or more of the following reasons: a lack of serious pest impacts, the quarantine outliving its ability to contain the pest, and/or federal deregulation.
Oak leafroller caterpillars web leaves together as they feed. Photo: Wisconsin DNR.
Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Watch for defoliators in your oak trees this summer. You may have already heard news reports about spongy moth caterpillar populations being high this year, but there are some native caterpillars to watch for this year as well.
In 2022, oak leafroller caterpillars caused significant defoliation to oaks in areas of northeastern and northwestern Wisconsin, as well as in Blue Mound State Park. Many other areas experienced lesser amounts of defoliation from oak leafroller.
By Bill McNee, DNR Forest Health Specialist, Oshkosh
bill.mcnee@wisconsin.gov or 920-360-0942
Spongy moth caterpillars clustered below a sticky barrier. Photo: Mark Guthmiller, Wisconsin DNR
This June and July, spongy moth populations are predicted to reach damaging levels in parts of Wisconsin. Populations began to rise in 2020, and this is likely to be the third year of the pest outbreak in some regions of southern Wisconsin.
At present, damaging populations are expected to be most noticeable in southern counties, counties to the north of the city of Green Bay, and in far northern Wisconsin near Lake Superior. Additional areas are likely to have high populations that are more concentrated in size.
Continue reading “Prepare — Spongy Moth Caterpillars To Return”
By Anne Pearce, Invasive Plants Association of Wisconsin
Spotted lanternfly is on its way to Wisconsin
Tree-of-heaven showing leaves and fruits. Photo: Chuck Bargeron, University of Georgia, Bugwood.org
Spotted lanternfly (Lycorma delicatula) is an invasive insect that threatens a variety of plant species, mostly woody plants. It has not yet been found in Wisconsin, but it is steadily moving toward us from the eastern United States. Both juvenile (nymphs) and adult spotted lanternfly feed by sucking sap from the stem, branches, twigs and leaves of host plants. This weakens the plant and can contribute to the plant’s death. Because spotted lanternfly impacts a wide variety of agricultural crops (like grapes and hops), nursery crops (like roses), and hardwood trees (like maple, walnut, willow, and poplar), it is a high priority pest in Wisconsin.
Continue reading “Report Tree-Of-Heaven To Help Monitor For Spotted Lanternfly”
By Bill McNee, Forest Health Specialist, Oshkosh, Bill.Mcnee@wisconsin.gov or 920-360-0942
Sites where EAB biological controls have been recovered as of March 2023. The Spathius galinae recovery site is indicated by a red star. Blue dots show Tetrastichus planipennisi recovery sites. Municipal EAB detections are in green. Map: Wisconsin DNR
Two adult wasps, collected last December as pupae from an emerald ash borer (EAB) gallery at Kiel Marsh State Wildlife Area in Manitowoc County, have recently been identified as Spathius galinae.
This find marks the first time that S. galinae has been recovered in Wisconsin, confirming that the adult wasps released at this site over the last few years were able to attack EAB larvae and reproduce successfully. The “EAB wasps” were released as biological controls to help reduce EAB populations over the long term.
This wasp species has a longer ovipositor than the other EAB larval parasitoid currently released in Wisconsin (Tetrastichus planipennisi), allowing S. galinae to attack EAB larvae that are beneath thicker bark.
Spathius galinae was first released in Wisconsin in 2016, and approximately 1,000 of this species were released at Kiel Marsh in 2019 and 2020. Recovery surveys are conducted several years after initial releases, giving the wasps time to reproduce and spread. Continue reading “First Recovery of Emerald Ash Borer Enemy Made”
By Bill McNee, Forest Health Specialist, Oshkosh, Bill.Mcnee@wisconsin.gov or 920-360-0942
Spray aircraft used in spongy moth control. Photo: Bill McNee
At a suitable time between early May and early June, an airplane will spray parts of four DNR properties to reduce the population of spongy moth caterpillars (formerly known as gypsy moth). Treatment dates will depend on weather conditions and caterpillar development.
This year’s high populations threaten to strip trees of their leaves and possibly kill high-value trees at these properties.
By Alex Feltmeyer, Forest Health Specialist, Plover, Alexandra.Feltmeyer@wisconsin.gov or 715-340-3810
A Heterobasidion root disease fruiting body is found at the base of a white pine sapling in the understory. Photo: Wisconsin DNR Forest Health
Heterobasidion Root Disease (formerly annosum root rot or Fomes root rot) is a serious disease of conifers that causes reduced height, shoot and diameter growth along with thin and yellowish/red foliage, ultimately causing mortality.
The disease becomes established in a new stand when spores of the fungus land on freshly cut stumps made by any forest management that creates cut stumps. After the disease becomes established, it spreads underground through root systems into adjacent trees. In this way, we often find pockets or groups of trees in various stages of decline.
Movement through the root systems contributes to significant spread throughout stands of conifers, impacting the regeneration of conifers within these pockets.
Mortality usually starts occurring three to eight years after a thinning operation. During this time, perennial fruiting bodies of the fungus begin to develop around the base of cut stumps or dead trees.
By Linda Williams, Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665
Squirrels remove the bark of maples, leaving bright bare spots. Photo: Wisconsin DNR
It’s the time of year when we start to see scattered maple trees stripped of their bark. Squirrels cause this damage — which can be limited to a few small areas the size of a tennis ball or can extend to cover many feet of branches or the main stem.
The squirrels are going after the cambium layer, just under the bark, that tastes slightly sweet from the sap. Smooth bark is easier for squirrels to chew, so young trees or branches with thin bark are likelier to be stripped than those with older, furrowed bark.
At this time of year, the pale wood of the branches that have had the bark stripped off is nearly white; later in the season, this wood will darken or even turn black with sooty mold. This type of feeding can remove enough bark to girdle the branches or the main stem, causing the tree to die from that point to the end of the branch.
Branches that are not completely girdled will continue to grow, and callus tissue will begin to grow over the wounds. If branches are nearly girdled, they may leaf out this spring and then suddenly wilt and die as hot weather hits because the tree can’t deliver enough water to keep those leaves alive. Continue reading “Hungry Squirrels Find Trees Tasty”
By Bill McNee, DNR Forest Health Specialist, Oshkosh, bill.mcnee@wisconsin.gov, 920-360-0942
In 2022, the number of municipal emerald ash borer (EAB) detections in Wisconsin crossed the 1,000 milestone. The 1,000th municipality (town, village or city) to have an EAB detection was the Town of Lincoln in Adams County on May 19. At the end of the year, EAB was known to be in 1,109 municipalities, up 23% from a year earlier.
Cumulative number of Wisconsin municipal EAB detections by year. Graph: Bill McNee, Wisconsin DNR.
Continue reading “More Than 1,000 Wisconsin Municipalities Now Known To Have Emerald Ash Borer”
