Pest

Prepare now – gypsy moth caterpillars return

Gypsy moth caterpillar with distinctive blue and red dots

Gypsy moth caterpillar with distinctive blue and red dots

This June, gypsy moth populations may rise to damaging levels in parts of Wisconsin. High numbers of gypsy moth caterpillars are a tremendous nuisance and can strip trees of their leaves. Combined with other stresses, such as drought or attacks by additional tree pests, this may kill the tree. The insect’s favorite food is oak leaves, but it will feed on many other tree species such as aspen, birch, crabapple and willow. You can take action to reduce the number of caterpillars that will feed on your trees, including placing sticky barrier bands on the susceptible tree species. Continue reading “Prepare now – gypsy moth caterpillars return”

Oak wilt and hickory mortality Forest Health Fact Sheets are available

The forest health program is in the process of updating some of our publications as Forest Health Fact Sheets. These publications offer biology, impact, prevention and management information about specific threats to forest health. Our new oak wilt fact sheet and hickory dieback and mortality fact sheet are currently available on the DNR’s forest health oak wilt and bark beetle webpages and will be available in the DNR’s online publications catalog  in the near future. Enjoy!

Written by: Mike Hillstrom, forest health specialist, Wisconsin Dells (Michael.Hillstrom@Wisconsin.gov), 715-459-1371.

Emerald ash borer new locations in Wisconsin

EAB quarantine map. Counties shaded in tan are quarantined for EAB, and include much of the southern half of Wisconsin, as well as other counties. Areas shaded in green are the townships and municipalities where EAB has actually been identified, and shows that not all counties that are quarantined are fully infested.

EAB quarantine map. Counties shaded in tan are quarantined for EAB, green areas are townships and municipalities where EAB has actually been identified.

Emerald ash borer (Agrilus planipennis) continues to be found in new areas. Wisconsin continues to track EAB at the municipality or township level; quarantine counties are shown in tan and infested areas are shown in green on the map.

If you know you have EAB, please contact us with that information so we can verify the infestation and update the maps. If your area:

  • is not shaded in green on the map please contact DNR or
  • is not shaded at all on the map please contact DATCP.

You can reach both agencies from the menu options when you call 1-800-462-2803.

New county quarantines

  • none

New finds in counties already quarantined

  • Brown County — village of Bellevue
  • Door County — village of Egg Harbor
  • Fond du Lac County — village of Rosendale and town of Springvale
  • Vernon County — town of Franklin

Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.

Slime molds and yeasts are bright and slimy

Several reports have recently come in of bright orange slime on trees or on mulch in Brown, Door and Shawano counties. Slime molds and yeasts can make bright colors, usually pink, orange, or yellow. Don’t panic – they don’t harm the tree. Often the orange, slimy areas on trees are associated with sapsucker wounds, where the tree has been bleeding sap on which microorganisms are growing. We see these most during the spring when the weather is moist, but once the weather warms the slime will dry up, leaving just a faint orange tinge to the tree where they were.

Sapsuckers wound trees and return to lick the sap that oozes from the wounds.

Sapsuckers wound trees and return to lick the sap that oozes from the wounds.

A stump is covered by orange slime. Slime molds and yeasts can be orange, pink, or yellow.

Slime molds and yeasts can be orange, pink, or yellow. Photo by: Gerald Vomastic

 

Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.

Eastern spruce dwarf mistletoe

Eastern spruce dwarf mistletoe (Arceuthobium pusillum), is a parasitic flowering plant that can be very damaging to black spruce, although it can also attack other spruces. Occasionally you’ll see it on other species growing amidst spruce such as tamarack, white pine, red pine, jack pine, or balsam fir. Continue reading “Eastern spruce dwarf mistletoe”

Forest tent caterpillar update

Forest tent caterpillars do not make web nests but may congregate and rest in groups on the bark.

Forest tent caterpillars do not make web nests but may congregate and rest in groups on the bark.

Caterpillars hatch from the eggs of a forest tent caterpillar egg mass.

Caterpillars hatch from the eggs of a forest tent caterpillar egg mass.

Forest tent caterpillars are hatching. Egg mass surveys were conducted in Iron, Ashland, Bayfield, Sawyer, Polk, Washburn, Douglas and Burnett counties, and no egg masses were observed. Surveys in Vilas, Oneida and Forest counties found very few egg masses.

Based on this information we expect low numbers and minimal defoliation again this year, but please let us know if you see forested areas with more significant defoliation.

Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.

 

Invasive insects and disease awareness month

Vin Vasive is the spokesman for invasive insects at USDA APHIS. He is made up of invasive species. This USDA APHIS poster was designed by Deb Levy Creative.

Vin Vasive is the spokesman for invasive insects at USDA APHIS. He is made up of invasive species. This USDA APHIS poster was designed by Deb Levy Creative.

April is invasive plant pest and disease awareness month, and May 21-27 is EAB awareness week.

It’s spring, and a good time to remember that invasive species can be easily moved long distances by unsuspecting citizens; maybe even you! All it takes to potentially start a new infestation is to move things we often like to take with us, but don’t know are a problem:

  • firewood,
  • infected or infested plant material,
  • an infected or infested piece of fruit, or
  • even a decorative piece of northwoods style furniture that hasn’t been properly treated to kill pests hiding inside.

Take a moment to think about whether you are unknowingly moving items that could harbor pests. The Hungry Pests website lists things you can do to prevent the spread of invasive species, whether you’re a birdwatcher, gardener, hunter, logger, or anyone. Check it out! While you’re there check out some short videos of their “spokesman” Vin Vasive, who has gotten much creepier over the years. 

Help spread the word

Coming up, May 21-27 is emerald ash borer awareness week, which is right before the Memorial Day holiday, when lots of travelling, camping, and opening up of summer cabins occurs. The Don’t Move Firewood website has a nice video of how to identify an EAB infested tree. More detailed videos are also available at dnr.wi.gov, keyword “forest health.” If you would like some examples of outreach tools or publications you can use to promote EAB awareness, check out the Don’t Move Firewood website; there you’ll find games for kids, an EAB craft project, videos, press releases, and news articles from past years. 

Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172. Categories: FH, UF. Tags: Statewide FH, Insect, Pest

DNR will conduct aerial spraying for gypsy moth in Madison, Monona and at Devils Lake State Park

Aerial spraying for gypsy moth is done by a loud, low flying airplane beginning early in the morning.

Spray aircraft used in gypsy moth control.

Residents in the Madison and Baraboo areas can expect a morning or two of loud, low-flying planes this May. The DNR Gypsy Moth Suppression Program will be spraying to control high populations of gypsy moth, an invasive and destructive pest whose caterpillars feed on the leaves of many tree and shrub species. Aerial spraying will occur in the following locations:

  • Cities of Madison and Monona: Three sites in and around Orton Park, Quaker Park, and Acewood/Elvehjem Parks
  • Devils Lake State Park: Day-use area at the south end of the lake, and the day-use area and several campgrounds at the north end of the lake.

Maps of the treatment areas can also be seen at the Wisconsin Cooperative Gypsy Moth Program website. Spraying is currently predicted to occur in mid-May, but actual dates will depend on weather conditions and caterpillar development.

Continue reading “DNR will conduct aerial spraying for gypsy moth in Madison, Monona and at Devils Lake State Park”

Forest tent caterpillar egg mass surveys indicate low populations again

Newly hatched forest tent caterpillars with the egg mass they emerged from. Egg masses are laid in mid-summer and remain on the tree through the winter.

Newly hatched forest tent caterpillars with the egg mass they emerged from. Egg masses are laid in mid-summer and remain on the tree through the winter.

Low numbers of forest tent caterpillar egg masses were found recently during surveys in Vilas and Oneida Counties. Forest tent caterpillar is a native insect that has periodic outbreaks. Our last outbreak was from 1999-2002, and they typically have outbreaks every 10-15 years. Last year I noticed a few more caterpillars than the previous year, but there was no noticeable defoliation. So far egg mass surveys indicate another year of low populations, although there may be areas with locally higher populations. Forest tent caterpillar eggs will start hatching soon, timed to closely match the emergence of aspen leaves.

Eastern tent caterpillars hatch from eggs and immediately start to create a web nest. Young caterpillars are shown on a small web nest.

Eastern tent caterpillars hatch from eggs and immediately start to create a web nest. Young caterpillars are shown on a small nest.

Eastern tent caterpillars do not follow a typical outbreak pattern and tend to be present at some low level every year. They create web nests early in the spring, preferring black cherry trees, crabapple trees, or other stone fruits. When webs are small the caterpillars can be easily crushed or sprayed. As webs get bigger you may have to use a rake to pull them out of the tree. It is not necessary to prune the branch out of the tree. Doing so will actually cause more damage to the tree than the defoliation caused by the caterpillars, because trees can more easily send out additional leaves than grow a branch to replace one you prune out. Please do not burn nests out of the trees as this could start a wildfire. 

 

Written by: Linda Williams, forest health specialist, Green Bay, (Linda.Williams@wisconsin.gov), 920-662-5172.