Pest

Make Your 2023 Spongy Moth Treatment Plans Early

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”

Harvest Timing Affected By Spongy Moth

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

Numerous spongy moth egg masses on a bur oak in southern Waukesha County, November 2022.

Numerous spongy moth egg masses on a bur oak in southern Waukesha County, November 2022. Photo: Bill McNee, Wisconsin DNR.

Forest managers planning silvicultural treatments in spongy moth susceptible stands (containing a large proportion of host species including oak, birch, aspen and basswood) are encouraged to annually conduct egg mass surveys in the few years prior to the scheduled treatment to predict if heavy defoliation is likely. The results may indicate that management activities should be altered or delayed until an outbreak has ended. At present, stands that were heavily defoliated in 2022 or are predicted to be heavily defoliated in 2023 are most likely to need a management delay or alteration.

It is recommended that a time interval be left between a stress agent (such as heavy defoliation or significant drought) and stand thinning so that the trees can recover from pre-existing stress before being subjected to additional stress. One growing season is a common interval for healthy stands that are not being subjected to drought or other stresses. A longer interval is suggested if the tree stress has been more severe or if the stand was not healthy and vigorously growing at the time of defoliation. The same interval is probably appropriate regardless of which stress agent is the pre-existing one. A protective aerial spray may prevent tree stress from defoliation but is usually not economically viable due to the high cost of an aerial treatment.

Continue reading “Harvest Timing Affected By Spongy Moth”

Twolined Chestnut Borer Attacks On The Rise

By Paul Cigan, DNR Forest Health Specialist, Hayward, Paul.Cigan@wisconsin.gov or 715-416-4920

Twolined chestnut borer (TLCB) attacks on oak trees have increased in numerous Wisconsin counties, with decline and associated mortality in the last two growing seasons, most noticeably since August.

Symptoms of infestation by this native beetle are initially seen in mid-July on the outer portions of branches in the upper crown. Leaves begin to fade from green to yellow to red. Within a matter of weeks, they turn brown and remain on the branches for weeks to months. Their foliage may also appear sparse or completely bare (Fig. 1).

Trees with twolined chestnut borer symptoms

Figure 1. Northern red oaks with symptoms of twolined chestnut borer, ranging from crown thinning and leaf chlorosis like the tree on the left (early stage) to dead top branches like the tree on the right (intermediate stage). Photo: Wisconsin DNR

Continue reading “Twolined Chestnut Borer Attacks On The Rise”

Moving Firewood Can Spread Invasive Species

An image of an insect walking away from burning firewood in a forest with the caption, “Buy it where you burn it.”

Don’t Move Firewood, The Nature Conservancy

October is Firewood Month! Help prevent the spread of invasive insects and diseases by buying firewood where you burn it.

Firewood Scout can help you find local firewood for sale.

See the DNR website for more information on invasive species and forest health. Continue reading “Moving Firewood Can Spread Invasive Species”

Check Conifer Trees For Severe Root Disease

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

Considered one of the most destructive diseases of conifers in the northern hemisphere, Heterobasidion root disease (HRD) is very difficult to control once established in a forest. Infestation of a conifer stand may significantly impact stand management, making early detection essential.

A pine stump with a Heterobasidion root disease fruit body with old brown growth in the center and new, bright white growth along the edges.

A Heterobasidion root disease (HRD) fruit body with new white growth observed in the fall. Photo: Wisconsin DNR

Continue reading “Check Conifer Trees For Severe Root Disease”

Grant Funds Available For Community EAB Management

By: Abigail Krause, DNR Urban Forestry Coordinator

As more detections of emerald ash borer (EAB) are confirmed in Wisconsin’s northern counties, many communities are just starting to address the management consequences that others having been dealing with for more than a decade. Members of the communities in which you live and work may vaguely know of you as “that one person that knows things about trees.” As such you may get asked: are there any cost-share funds or programs out there to help communities deal with EAB?

The answer is yes! Urban Forestry’s grants can be utilized for EAB related projects. Extra great news: urban forestry regular and startup grants are accepting applications until Monday, Oct. 3.

Continue reading “Grant Funds Available For Community EAB Management”

Look For Spongy Moth Egg Masses – Larger Outbreak Possible in 2023

By: Bill McNee, DNR Forest Health Specialist, Oshkosh

bill.mcnee@wisconsin.gov or 920-360-0942

Three tan-colored spongy moth egg masses on a single tree branch in Walworth County.

Three spongy moth egg masses on a branch in Walworth County. Photo Credit: Bill McNee, Wisconsin DNR

Now that spongy moth* (formerly known as gypsy moth) egg laying is complete for 2022, it’s a good time to look for and dispose of egg masses produced by adult moths over the past two months.

Spongy moth egg masses are tan-colored lumps about the size of a nickel or quarter, and are found on trees, buildings and other outdoor objects. They may also be found in protected places such as firewood piles and birdhouses. Newly produced egg masses will feel firm and appear darker in color than older egg masses, which appear faded, feel spongy and do not contain viable eggs. The current-year egg masses will not hatch until next spring.

In 2022, Wisconsin’s spongy moth population grew for a third consecutive summer due to favorable weather conditions and limited caterpillar mortality from diseases. The outbreak was most dramatic in opposite ends of the state. In southern and southeast Wisconsin, several thousand oak-dominated acres were heavily defoliated and very large numbers of property owner reports were received by DNR staff. In Bayfield County, about 80,000 acres of rural defoliation was reported from aspen-dominated forests. Smaller patches of defoliation were also reported from several other counties. Continue reading “Look For Spongy Moth Egg Masses – Larger Outbreak Possible in 2023”

Aspen Leaf Diseases Responsible For Thin Crowns

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

Northeastern Wisconsin saw thin and defoliated aspen trees in early summer this year due to a few diseases. A sample from Marinette County turned up Alternaria leaf and stem blight, Venturia leaf and shoot blight and Phyllosticta leaf spot. Venturia was also noted in central Wisconsin, causing shoot blight, which kills the terminal leaders (growth buds) of young aspen.

Aspen trees with leaves damaged by leaf disease..

Aspen crowns were thin due to multiple leaf diseases. Photo: Wisconsin DNR

Continue reading “Aspen Leaf Diseases Responsible For Thin Crowns”

Pine Sawyer Beetle: A Noteworthy Native

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

This time of year, you may see black beetles with long antennae flying around, especially in areas with pine trees. These slow, ungainly flyers are a native longhorn species called white-spotted sawyer beetle, also known as pine sawyer.

Pine sawyers are black beetles with long antennae.

Pine sawyer adult male. Photo: Wisconsin DNR

Continue reading “Pine Sawyer Beetle: A Noteworthy Native”

Hungry, Hungry Japanese Beetles

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

Japanese beetles (Popillia japonica) are an invasive insect that feed on many plant species. They skeletonize leaves, which means that they eat the material between the veins and often leave lacy veins that turn brown and curl.

An adult beetle on a leaf.

Japanese beetle adult. Photo: Wisconsin DNR

Continue reading “Hungry, Hungry Japanese Beetles”