Past reports from the 1992 and 1967 WI DNR Forest Health Annual Reports
25 years ago – 1992
“European fruit lecanium (Parthenolecanium corni (Bouche))
Heavy infestations of this scale insect were reported on sugar maple twigs in Vilas and Price counties.
Jack pine budworm (Choristoneura pinus (Rohwer))
The outbreak in the northwestern counties, which began in 1991, exploded this year (Figure 16). Over 114,000 acres of jack pine were heavily defoliated in Douglas, Bayfield, Washburn and Burnett counties. Egg mass surveys indicate extremely high numbers of jack pine budworm. The area of defoliation may increase in 1993. The present defoliation is not expected to cause significant mortality except in Highland Township, but another year of heavy defoliation in the same stands could cause 10-15 percent mortality. In Highland Township, Douglas County, extremely severe feeding produced significant. mortality and top dieback on several thousand acres of jack pine. Most of these stands are being harvested this winter. Moderate to heavy defoliation also occurred in Jackson, Juneau, Eau Claire, Marinette (1,650 acres), Vilas (2,960 acres) and Oconto counties. In Marinette County, 20 acres of 70-year-old jack pine were cut to release young jack pine and white pine. Jack pine budworm was causing severe top mortality. Evidence of budworm in the northern portion of the Monroe County Forest was observed on 35-40 year old jack pine (Sections 4, 9,16, T19N, R3W). DNR foresters have silvicultural guidelines available to manage budworm-prone jack pine stands.”
Continue reading “Of historical interest…”
Oak leaf from the first oak wilt detection site in Sheboygan County, showing bronzing coloration characteristic of oak wilt infection. Photo: William McKnee, WI DNR
Oak wilt, a deadly fungal disease affecting the red oak group, was recently detected in Sheboygan County for the first time. Wood samples were collected from adjacent symptomatic oak trees on the Kettle Moraine State Forest – Northern Unit in the Town of Mitchell after the trees were spotted by DNR Forestry staff. The presence of Ceratocystis fagacearum, the fungus causing oak wilt, was confirmed through a DNA test done at the DNR Forest Health Lab and DNA sequencing done at the UW-Madison Biotechnology Center. On-the-ground control options are currently being examined.
Oak wilt is a common disease in the southern two-thirds of the state, but has been
Map of counties where oak wilt has been detected, with the recent Sheboygan County confirmation shown in orange.
increasingly found in the northern counties. DNR staff have recently reported first community detections in these northern counties already known to have the disease:
- Langlade County – Town of Langlade
- Sawyer County – Town of Edgewater
- Washburn County – Town of Stone Lake
Oak wilt has been found in all Wisconsin counties except Ashland, Bayfield, Calumet, Door, Douglas, Forest, Iron, Kewaunee, Manitowoc and Taylor.
Additional information about oak wilt can be found at the DNR Forest Health website.
Written by Bill McNee, DNR Forest Health Specialist, Oshkosh. Bill.McNee@wisconsin.gov; 920-360-0942
Since the August newsletter, it was announced that six new counties would be quarantined for emerald ash borer (EAB). The find in Chippewa County was due to a vigilant landowner while the other finds were due to trapping by USDA APHIS.
WI counties quarantined for EAB (DATCP). Most of Wisconsin is EAB-free, including most of the northern half and the yellow areas in all
quarantined counties. EAB has been confirmed only in those cities, villages and townships
colored dark green.
Continue reading “Six new counties quarantined for EAB”
Gypsy moth egg mass
Early fall is the best time for property owners to determine whether gypsy moths will be a problem next year. Gypsy moth egg masses are tan-colored and about the size of a nickel or quarter. Egg masses will not hatch until next spring, which means landowners have plenty of time to plan to minimize gypsy moth damage next summer. New egg masses produced this year feel hard, whereas those that are older are soft and appear faded. Most egg masses will be found on tree trunks and the undersides of branches, but they can also be found on buildings, firewood piles, vehicles and other outdoor objects.
Continue reading “Look for next year’s gypsy moth infestations”
Common buckthorns retain leaves late into the fall.
The following article offers a glimpse of the good work that happens after DNR awards grants through its Weed Management Area – Private Forest Grant Program (WMA-PFGP). Dick Ballou, the driving force of the Cedar Lake Buckthorn Project, takes us through his efforts to raise awareness of that forest scourge -common buckthorn- and control its spread. The next application deadline for WMA-PGRP grants is April 1, 2018. More information on applying for the grant can be found here.
Imagine the frustration of eagerly awaiting your opening day of deer hunting, having your stand in a perfect location and learning at daybreak that the woods around your stand are not as you expected? Several years ago, I prepared for bow hunting and found a perfect location for the deer stand, except for one small problem, a 20-foot tall tree full of leaves. Thinking the tree’s leaves would be gone by mid-October, I placed the stand nearby and went home. Returning in October, the “perfect” location was seriously compromised by the same tree – full of leaves – obstructing my view. Later, I learned the tree was invasive common buckthorn that currently threatens woodlots from New England to Wisconsin and beyond. This experience led me to start the Cedar Lake Buckthorn Project and create this video on buckthorn control. Continue reading “New video on buckthorn control available”
It’s official. January through July 2017 was the wettest Wisconsin has experienced in the 123 years data has been collected. The average across the state was 25.25 inches, which is 7.14 inches above average according to the National Weather Service.
Total precipitation percentiles for the United States from January through July 2017. Overall, and for multiple areas of Wisconsin, it has been the wettest January through July ever recorded. Figure from NOAA
Flood and other storm damage have occurred to forests and urban trees in many areas of Wisconsin. We suspect storm damage from May to July has led to a number of new oak wilt infestations in impacted areas. The wet weather has also led to abundant leaf and needle diseases such as anthracnose. Plentiful precipitation has similarly played a role in insect populations. Japanese beetle larvae thrive with consistent soil moisture and the consistent rain in recent years has resulted in large populations of this pest across the Midwest. In contrast, the wet, humid spring led to another year of high mortality rates for gypsy moth caterpillars from disease.
Written by Mike Hillstrom, forest health specialist, Fitchburg (Michael.Hillstrom@Wisconsin.gov), 608-513-7690.
You may be noticing leaves of various hardwood trees already turning to fall color in lowland areas. These lowland areas are holding more water this year and it is affecting the trees. The trees in these areas are stressed from being in water too long, and this is causing the hardwoods leaves to turn color early. Some of the hardwoods are dying in these lowland areas, and most conifers in these areas are also dying due to too much water.
Hardwood leaves turning to fall color
Written by: Todd Lanigan, forest health specialist, Eau Claire (Todd.Lanigan@wisconsin.gov) 715-839-1632
Ladybug adults and larvae are great predators of aphids and scales and help keep those pests in check. Ladybug larvae don’t look much like ladybugs though, so you may not notice them, or you may wonder what the tiny monster is that’s munching on aphids. Ladybug larvae come in a variety of colors and shapes. Several people have described them as looking like a small dragon, or for those of you from Rhinelander, perhaps they look like a tiny Hodag.
I recently came across a critter that I would have never guessed was a ladybug larvae; it looked more like a mealybug to me. It was on red pine, and there were no aphids on the red pine, so nothing triggered me to think “ladybug larvae.” After snapping a few pics, I dismissed it as an oddity. But of course oddities are just mysteries waiting to be solved. Mike Hillstrom, my counterpart in Fitchburg, helped narrow this down to a ladybug larvae. Ladybugs in the Hyperaspis genus have larvae that look like mealybugs, and those ladybugs (both larvae and adults) specialize in feeding on pine tortoise scale! How fitting since I found it on red pine!
The following photos illustrate that ladybug larvae come in many shapes, sizes, and colors.
This ladybug larvae, in the genus Hyperaspis, looks like a mealybug and specializes in feeding on pine tortoise scale.
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232
Much of Wisconsin has reached peak emergence of emerald ash borer adults.
EAB emergence map as of August 28, 2017. In the north the light green shows peak emergence, and olive is past peak emergence.
EAB continues to be found in new areas. Wisconsin tracks EAB at the municipality or township level. Quarantine counties are shown in tan and infested areas are shown in green on the map below.
EAB quarantine map. Counties shaded in tan are quarantined for EAB, green areas are townships and municipalities where EAB has actually been identified.
Click here for a larger version of the map: EABDetectionsQuarantines
New county quarantines:
New finds in counties already quarantined:
- Columbia County – town of Caledonia and villages of Poynette and Rio
- Crawford County – village of Soldiers Grove
- Dodge County – towns of Herman and Theresa
- Fond du Lac County – village of Campbellsport
- Grant County – city of Boscobel
- Green County – town of Sylvester
- La Crosse County – city of West Salem
- Manitowoc County – city of Manitowoc
- Sheboygan County – village of Howards Grove, towns of Mosel, Rhine and Russell
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232.
Oak wilt symptoms are active right now, but so are several other oak leaf diseases. Can you tell the difference?
Trees with oak wilt will suddenly start to drop their leaves in July and August. These leaves will be either tan or a water-soaked greenish color away from the petiole (leaf stem). Near the petiole there will often be an area that is still green, even though the leaf has fallen to the ground. Symptoms typically start near the top of the tree and progress downwards.
Leaves dropped from a tree dying from oak wilt. Note the discoloration on the distal portions of the leaf, while the petiole area is still green.
Oak wilt leaves often drop from the top of the tree first.
Anthracnose is a fungal leaf disease that is quite common this year due to the wet weather that we’ve had. Anthracnose is not fatal to the tree and the tree will hold these leaves throughout the season. Irregular areas of the leaf will be dead, and if this infection occurred when the leaf was expanding the leaf will often end up misshapen or puckered.
Anthracnose causes irregular dead blotches on the leaf.
Tubakia is another leaf disease that we will sometimes see. Symptoms are typically worse in the lower canopy. Leaves may drop from the tree but the pattern of mortality on the leaf will be different than what you see with oak wilt.
This oak is being affected by Tubakia, a fungal leaf disease. Symptoms are significantly worse in the lower canopy.
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232.