Pest

Aerial Spraying Set For Four State Sites

Posted on by akabelowsky

By Bill McNee, Forest Health Specialist, Oshkosh, Bill.Mcnee@wisconsin.gov or 920-360-0942

Spray aircraft used in spongy moth control

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.

Continue reading “Aerial Spraying Set For Four State Sites” →

Heterobasidion Root Disease Approaches

Posted on by akabelowsky

By Alex Feltmeyer, Forest Health Specialist, Plover, Alexandra.Feltmeyer@wisconsin.gov or 715-340-3810

A Heterobasidian root disease fruiting body at the base of a white pine sapling

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.

Continue reading “Heterobasidion Root Disease Approaches” →

Hungry Squirrels Find Trees Tasty

Posted on by akabelowsky

By Linda Williams, Forest Health Specialist, Woodruff, Linda.Williams@wisconsin.gov or 920-360-0665

Maple branches with light colored areas where squirrels removed bark.

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” →

More Than 1,000 Wisconsin Municipalities Now Known To Have Emerald Ash Borer

Posted on by patricialindquist

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.

Graph showing cumulative number of Wisconsin municipal emerald ash borer detections by year.

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” →

First Anniversary Of Spongy Moth’s Name Change

Posted on by patricialindquist
Spongy moth caterpillar

Spongy moth caterpillar. Photo credit: Jon Yuschock, Bugwood.org

March 2, 2023, marks one year since a new common name for Lymantria dispar, spongy moth, replaced the prior name of this insect, “gypsy moth.” This change was necessary because the word “gypsy” is an ethnic slur for the Romani people and the former common name equated people with insects. This is the first name change undertaken by ESA (Entomological Society of America)’s Better Common Names Project.

The current name—derived from the common name used in France and French-speaking Canada, “spongieuse“—refers to the moth’s sponge-like egg masses. Lymantria dispar is a damaging pest. This current name is a critical move in public awareness that focuses on an important feature of the moth’s biology while moving away from an outdated term. We encourage you to review any materials you may have on your website, ordinances and other material related to forest pests to ensure they are in accordance with this name change.

Continue reading “First Anniversary Of Spongy Moth’s Name Change” →

Wisconsin DNR 2022 Forest Health Annual Report

Posted on by patricialindquist

By Becky Gray, Forest Health Team Leader, Rebecca.Gray@wisconsin.gov

The Wisconsin Department of Natural Resources’ Forest Health team recently completed the 2022 Forest Health Annual Report. The report summarizes impacts from pests, diseases and weather on the health of Wisconsin’s forests. Highlights from 2022 include:

  • Spongy moth’s rising numbers and evaluation of control techniques;
  • emerald ash borer continuing to spread and kill ash trees;
  • possible new biological control of buckthorn; and
  • drought and flooding impacts alongside insect infestations.

Read the report here.

2022 Forest Health Annual Report

Make Plans To Control Spongy Moth Before The Eggs Hatch

Posted on by patricialindquist

By Bill McNee, DNR Forest Health Specialist, Oshkosh, Bill.McNee@wisconsin.gov or 920-360-0942

Spongy moth (formerly known as gypsy moth) egg masses typically begin to hatch in April as temperatures warm. Each mass that hatches may produce up to 1,000 leaf-eating caterpillars.

Now is a great time to inspect your trees for egg masses and treat or remove any masses within reach. Wisconsin weather has been favorable for this pest over the last three years and populations have grown.

Photo of three spongy moth egg masses on the underside of a pine branch in Walworth County.

Three spongy moth egg masses on the underside of a pine branch in Walworth County. Photo: Bill McNee, Wisconsin DNR.

Continue reading “Make Plans To Control Spongy Moth Before The Eggs Hatch” →

Spongy Moth Management Webinar: March 8 at 6 p.m.

Posted on by patricialindquist

By Michael Hillstrom, Forest Health Specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov

Spongy moth populations increased dramatically in 2022 and the outbreak is expected to continue in 2023.

Landowners interested in learning more about spongy moth management options are encouraged to attend an upcoming webinar hosted by UW Extension at 6 p.m. on March 8, 2023.

This is a free event, but registration is required. DNR Forest Health Specialist Mike Hillstrom and UW-Madison Insect Diagnostic Lab entomologist PJ Liesch will discuss a variety of effective management tactics for reducing spongy moth damage in varied settings from high value urban trees to forests.

A flyer for an upcoming webinar about spongy moth management that will take place virtually at 6pm on March 8, 2023.

UW Extension’s spongy moth management webinar can help you prepare to care for your land this spring.

Treat Your Valuable Ash Trees Against Emerald Ash Borer This Spring

Posted on by patricialindquist

By Bill McNee, 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.

Woodpecker damage during the winter is often the first sign that an ash tree is infested. The birds remove pieces of bark while feeding on EAB larvae inside the tree. Insecticide treatment of infested ash trees is more likely to be successful if the trees have low or moderate levels of woodpecker damage.

Now is a good time to consider insecticide protection, because the treatments are typically done between mid-April and mid-May. Ash (in the genus Fraxinus) is the only type of tree that needs protection against EAB. Mountain ash and prickly ash do not need protection because the insect does not attack them.

Ash tree branch in West Allis has been damaged by woodpeckers. Sections of bark are missing, exposing the tree’s light brown wood.

This ash tree branch in West Allis has been damaged by woodpeckers feeding on EAB larvae beneath the bark.
Photo: Bill McNee, Wisconsin DNR.

Continue reading “Treat Your Valuable Ash Trees Against Emerald Ash Borer This Spring” →

Make Your 2023 Spongy Moth Treatment Plans Early

Posted on by brenna.denamur

By Bill McNee, DNR Forest Health Specialist, Oshkosh
bill.mcnee@wisconsin.gov or 920-360-0942

As long as weather conditions are favorable for the spongy moth* (formerly known as gypsy moth) population, the current outbreak is predicted to continue and spread to other parts of Wisconsin in 2023. Property owners are encouraged to examine susceptible host trees (including oak, birch, crabapple, aspen and willow) and plan ahead.

Spongy moth egg masses on a tree next to a penny for size comparison.

Spongy moth egg masses are tan-colored lumps that are larger than a penny, about the size of a nickel or quarter. Photo: Wisconsin DNR

Continue reading “Make Your 2023 Spongy Moth Treatment Plans Early” →