Emerald ash borer (EAB) continues to be found in new areas in the state. Wisconsin tracks EAB at the municipality or township level. Quarantined counties are shown in tan; infested areas are shown in green on the map.
New county quarantines
EAB quarantine map. Counties shaded in tan are quarantined for EAB, green areas are townships and municipalities where EAB has been confirmed. Map courtesy of WI DATCP.
New finds in counties already quarantined
- Monroe County — Town of New Lyme
- Richland County — City of Richland Center
Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211, x232
Spruce beetle (Dendroctonus rufipennis). Photo: Edward H. Holsten, USDA FS, Bugwood.org
The Division of Forestry’s forest health team recently updated another forest health fact sheet about conifer bark beetles. Like the oak wilt and hickory dieback and mortality fact sheets revised earlier this year, the conifer bark beetle publication offers information about biology, impact, prevention and management of the insects. The conifer bark beetle fact sheet is available on the DNR’s forest health webpage.
Written by: Mike Hillstrom, forest health specialist, Wisconsin Dells. Michael.Hillstrom@Wisconsin.gov; 608-513-7690
New needles are green (circled in red), and older needles are yellow (circled in blue) on this spruce. Spruce needles that are yellow with no visible fruiting bodies on the needles may be suffering from nutrient deficiency due to constant wet soils this year, or they may have a fungal disease called SNEED (spruce needle drop). Photo by Linda Williams, WI DNR.
In late summer and early fall I had a few calls about younger spruce with yellow needles. These trees were typically 8-20 years old and were a very yellow color, with new foliage emerging a green color but quickly fading to yellow. There are two things that came to mind this year. The first thought is that we’ve had a very wet year. All year long roots were often in saturated or very moist soil. Consequently. the yellowing could be a sign of nutrient deficiency, specifically nitrogen, due to the saturated soils. The second possibility is a disease called SNEED (an abbreviation for ‘spruce needle drop’), which I typically see on heavier soils.
SNEED in spruce is thought to be caused by the fungus Setomalonomma holmii. Pathogenicity of the fungus has not been proven, but it is the primary fungus present on trees with a particular suite of symptoms. Spruce with SNEED have current year needles that are a nice green color, but older needles will be yellow or yellow/green in color. Black fruiting bodies will look like pepper sprinkled generously on the twigs of the affected branches. Old needles, although not showing any fruiting bodies, will drop from the tree prematurely, and repeated years of this will cause the tree to thin, decline, and can lead to mortality. I’ve seen this primarily in plantations of white spruce on heavy soils, but have also seen it in blue spruce plantations; it’s reported in Norway spruce as well. I don’t know of any sure-fire chemical options to prevent infection or to help the trees recover. Management typically involves removing the most affected trees in the plantation, minimizing stress, and minimizing standing water or waterlogged soils where possible.
Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211, x232.
Jack pine budworm caterpillar on jack pine. Photo: Todd Lanigan, WI DNR
I conducted surveys for jack pine budworm caterpillars and egg masses in Dunn, Eau Claire, Jackson, Monroe, Pierce, and St. Croix counties last spring (caterpillars) and this fall (egg masses). Fortunately, I did not find any caterpillars and only one egg mass on red pine in Pierce County. Based on information from these surveys, jack pine budworm should not be a problem in 2018.
Jack pine budworm egg mass on jack pine needle. Photo: Todd Lanigan, WI DNR
In Wisconsin, jack pine budworm is a pest of jack, red, and white pine. It has rarely been found on white spruce, and in those cases only when the trees were located next to an infested plantation. Jack pine budworm can cause problems in natural stands, plantations, edge plantings/aesthetic strips, yard trees, and anywhere host trees are found.
For more information on management of jack pine in the state, click here.
Written by Todd Lanigan, forest health specialist, Eau Claire. Todd.Lanigan@wisconsin.gov; 715-839-1632
Multicolored Asian ladybeetles search for places to spend the winter and often congregate in protected places. Photo: Linda Williams, WI DNR
This fall, some areas of the state saw large numbers of ladybugs (specifically multicolored Asian ladybeetles) congregating as fall gave way to colder temperatures. Box elder bugs, leaf-footed bugs (or western conifer seed bugs), and brown marmorated stink bugs were also seen congregating this fall in areas of the state where they have been found before. These insects are attracted to homes and will attempt to find a way inside to spend the winter in a protected place. The urge to look for an overwintering spot is triggered by the first hard frosts and freezes of the season, but this year we had a fabulous warm-up after a cold spell which allowed the insects ample time to congregate on houses.
A Western conifer seed bug (sometimes called leaf footed bugs) on the left, and boxelder bug on the right. These two species also congregate in the fall as they look for warm protected places to spend the winter. Photo: Linda Williams, WI DNR
If you’re having problems with these insects invading your house you can try to “build them out”. Spraying the exterior of your house with appropriate pesticides to keep them out (which will repel all insects for a time) works well but it’s recommended this is completed by the last week of September or first week of October. UW Extension offers a fact sheet that gives suggestions for keeping ladybugs out of your home. When I get calls about ladybugs or box elder bugs inside the home, I recommend vacuuming the critters up, but always avoid squishing, since squishing them will stain whatever they are crushed on. Be sure to empty vacuum bags that have ladybugs in them as the ladybugs will start to smell after they die.
It’s not unusual for me to hear of folks mixing up multicolored Asian ladybeetles with Japanese beetles … they’re two different critters. And, yes, multicolored Asian ladybeetles are indeed ladybugs. Both exotic and native ladybugs feed on aphids and scales which means that they’re beneficial, but only the exotic ones will try to spend the winter in your house or garage.
Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232
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