By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665
Wisconsin has a few leaf-eating caterpillar species that are out early in the spring. Forest tent caterpillars, eastern tent caterpillars and spongy moth caterpillars cause varying levels of tree damage and are often mistaken for one another.
Forest tent caterpillars congregating on the trunk of a tree. Photo: Wisconsin DNR
Continue reading “Hairy Spring Caterpillars – Which One Do You Have?”
By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov or 920-360-0665.
Introduced basswood thrips are tiny, invasive insects that feed inside tree buds in early spring. Leaves are then deformed when they expand and can look like frost or wind has damaged them.
An adult introduced basswood thrips on the underside of an emerging basswood leaf. This photo is enlarged under a microscope. To the naked eye, they appear as tiny black specks on the underside of the leaf. Photo: Wisconsin DNR
Continue reading “Basswood Thrips: Tiny Terrors Of Basswood Leaves”
By Brenna DeNamur, DNR Forest Health Outreach Specialist, Madison, Brenna.DeNamur@wisconsin.gov
The Forest Health Team has made many changes since the spongy moth’s* (formerly known as gypsy moth) new name debut in March. Earlier this month, we launched the new and improved Spongy Moth Portal!
The University of Wisconsin-Madison Division of Extension recently updated three emerald ash borer (EAB) management factsheets:
Additional EAB resources from the Extension are available here.
To learn more about best practices for managing EAB in your community, check out the DNR’s Emerald Ash Borer Community Toolbox and Forest Health Emerald Ash Borer webpage.
By Linda Williams, DNR Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665 & Paul Cigan, DNR Forest Health Specialist, Hayward, Paul.Cigan@wisconsin.gov, 715-416-4920
Emerald ash borer (EAB) has been detected for the first time in Forest County in the Town of Armstrong Creek and Ashland County in the City of Ashland. The Forest County detection was most likely a natural expansion of other infestations in Florence and Marinette counties.
This Forest County tree was infested with EAB top to bottom. Photo: Wisconsin DNR
The Ashland County detections appear to be isolated infestations likely spread through the transportation of firewood or logs. Several large green ash stands in the City of Ashland show advanced infestation signs.
EAB was first found in Wisconsin in 2008. There are now just seven counties where EAB has not yet been identified. EAB was federally deregulated as of January 2021. In 2018, Wisconsin instituted a state-wide quarantine. This discovery in Forest and Ashland counties will result in no regulatory changes.
Please visit the interactive Wisconsin EAB detections map to see where EAB has been reported. Follow the map’s instructions if you know of an infested area not on the map. Continue reading “EAB Identified For The First Time In Forest And Ashland County”
USDA staff cut a ‘bark window’ in green ash to uncover signs of emerald ash borer.
Emerald ash borer (EAB) is an invasive insect from Asia first introduced into the United States in 2002. Since its discovery, EAB has caused tens of millions of ash trees to die and decline. Today, the U.S. Department of Agriculture (USDA) uses ash trees against the pest to help preserve and protect the tree species. They are asking Wisconsin landowners for their help.
Wisconsin landowners have donated live, infested ash trees to USDA’s EAB biological control program. The staff will then use the wood to cultivate EAB’s natural enemies and release them in Wisconsin and 28 other EAB-infested states. The biocontrol staff will need more ash trees to continue producing and releasing these stingless wasps that attack and kill EAB and are hoping more Wisconsin residents will consider donating their ash trees this year.
Continue reading “USDA Biological Control Facility Seeks Ash Trees To Battle Emerald Ash Borer”
By Paul Cigan, DNR Forest Health Specialist
Paul.Cigan@wisconsin.gov or 715-416-4920
Emerald ash borer (EAB) has been discovered in Bayfield County for the first time in both the city of Bayfield and Bayview township to the south. This marks the 63rd out of Wisconsin’s 72 counties to have an EAB discovery since its initial detection in 2008.
Figure 1: First known infested ash tree in Bayfield County with characteristic woodpecker damage (i.e., flecking).
Photo: Wisconsin DNR
Several white ash trees (Fig 1.) were observed in and around a roadside park in the city of Bayfield, and larval specimens were subsequently lab-confirmed. In Bayview, a black ash swamp had several infested black ash (Fig 2).
After introduction, EAB populations remain low for at least several years as most larvae in newly infested, healthy ash require two years to complete their life cycle. The abundance of healthy ash at each site suggests EAB populations have remained low since their introduction at least three years ago. However, EAB will kill ash more quickly as beetle numbers mount and more larvae transform from egg to adult in a single year. Unfortunately, many ash in the area are expected to die within four to seven years based on detection-to-impact timeframes observed from the Superior and Duluth area and research conducted in midwestern states. Continue reading “Emerald Ash Borer Found In Bayfield County”
By Josh Lancette, Entomological Society of America and Andrea Diss-Torrance, Wisconsin DNR Forest Health
The Entomological Society of America (ESA) has approved “spongy moth” as the new common name for the moth species Lymantria dispar, formerly known as “gypsy moth.”
The ESA gathered a working group of entomologists and forestry professionals to help propose the new name. The name spongy moth—derived from the common name used in France and French-speaking Canada, “spongieuse”—refers to the sponge-like appearance of the egg masses.
The name replaces “gypsy moth” in ESA’s Common Names of Insects and Related Organisms List. The society removed the name in July 2021 for its use as a derogatory term for Romani people.
By Bill McNee, DNR Forest Health Specialist, Oshkosh
bill.mcnee@wisconsin.gov or 920-360-0942
Property owners with healthy, valuable ash trees are encouraged to treat them with insecticide this spring to protect against emerald ash borer (EAB). The pest is currently the most damaging threat to trees in Wisconsin, killing more than 99% of the ash trees it infests.
This ash tree branch in West Allis has been damaged (“flecked”) by woodpeckers feeding on EAB larvae under the bark.
Photo: Bill McNee, Wisconsin DNR
Continue reading “Protect Your Valuable Ash Trees Against Emerald Ash Borer”
By Bill McNee, DNR Forest Health Specialist, Oshkosh
bill.mcnee@wisconsin.gov or 920-360-0942
Three spongy moth egg masses on the underside of a pine branch in Walworth County.
Photo: Bill McNee, Wisconsin DNR
Spongy moth* (formerly known as gypsy moth) egg masses typically begin to hatch in April as temperatures warm. Now is a great time to inspect your trees for egg masses and treat or remove any masses within reach. Each mass that hatches may produce up to 1,000 leaf-eating caterpillars.
Populations of spongy moths increased in 2020 and 2021 due to favorable weather conditions. This winter’s temperatures have not been cold enough to cause heavy egg mortality. A large rise in caterpillar numbers can be expected in 2022 if weather conditions are warm and dry over the next few months.
