Insect

Spruce budworm defoliation showing up

Posted on by colleenrobinson
The two center balsam fir are severely defoliated by spruce budworm while the outer two trees are less severely defoliated.

The two center balsam fir are severely defoliated by spruce budworm while the outer two trees are less severely defoliated.

Spruce budworm defoliation is starting to show up in the northern counties as the clipped foliage stuck in the caterpillar webbing turns rusty red. Defoliation this year may be reduced in some areas if the caterpillars were damaged by the multiple storms we’ve had this spring. Let us know where you’re seeing defoliation. The caterpillars should be pupating soon and moths will emerge a couple weeks after pupation. Spruce and balsam fir are defoliated by this pest, which is a native insect with periodic outbreaks. 

Outbreaks occur every 30-50 years, and last for 10 years on average. Our previous outbreak ran from 1970-1980. Mature balsam fir and spruce are preferred hosts, although younger balsam or spruce can be defoliated as well. Repeated defoliation can cause top-kill and eventually whole tree mortality. Balsam fir stands, or stands with a heavy component of balsam fir, are often more severely impacted, but don’t let that fool you into thinking it won’t defoliate pure spruce stands.  Continue reading “Spruce budworm defoliation showing up” →

Prepare now – gypsy moth caterpillars return

Posted on by colleenrobinson
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

Posted on by colleenrobinson

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

Posted on by colleenrobinson
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.

Forest tent caterpillar update

Posted on by colleenrobinson
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.

 

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

Posted on by colleenrobinson
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

Posted on by colleenrobinson
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.

 

Emerald ash borer new locations in Wisconsin

Posted on by colleenrobinson
EAB quarantine map. Counties shaded in tan are quarantined for EAB, and includes 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 and detections 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; quarantined counties are shown in tan and known 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

  • Adams/Columbia/Juneau/Sauk counties — city of Wisconsin Dells
  • Brown County — village of Allouez
  • Crawford County – town of Bridgeport
  • Columbia County – town of Lowville
  • Columbia/Dodge counties – village of Randolph
  • Dane County – village of DeForest
  • Green County – town of Monroe
  • Jackson County — towns of Melrose and North Bend
  • Jefferson County – towns of Aztalan, Farmington, Hebron, and Sumner
  • La Crosse County – town of Shelby
  • Monroe County – city of Sparta
  • Rock County – towns of Clinton, Harmony, Johnstown, and Lima
  • Sheboygan County – village of Kohler
  • Trempealeau County — towns of Ettrick, Gale and Preston

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

 

Emerald ash borer trapping in 2017

Posted on by colleenrobinson

The Wisconsin DNR forest health team is planning to trap for emerald ash borer (EAB) at 20 locations in 2017.

Emerald ash borer traps will be placed at 12 locations in northwest Wisconsin in 2017: Big Bay State Park, Amnicon Falls State Park, Pattison State Park, Brule River State Forest, Governor Knowles State Forest, Interstate State Park, Willow River State Park, Eau Claire, Smith Lake County Park, Flambeau River State Forest, Big Falls County Park, and Pershing State Wildlife Area.

EAB trap locations in northwest Wisconsin in 2017.

Emerald ash borer traps will be placed at 8 locations in northwest Wisconsin in 2017: Northern Highlands American Legion State Forest, Governor Thompson State Park, Hartman Creek State Park, Poygan Marsh Wildlife Area, River Side Park, Princeton, Dodge Memorial Park, and Grand River Marsh Wildlife Area.

EAB trap locations in northeast Wisconsin in 2017.

Traps will mostly be placed on state properties. A couple traps will be placed on county land where state properties are not in the local area. Traps are deployed close to 400 growing degree days so they are ready when EAB adults start emerging at approximately 450 degree days. In 2016, southern Wisconsin hit 450 degrees days (modified base 50°F) in late May.

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