Invasive stink bug numbers increasing

Posted on by Ellen Clark

By Mike Hillstrom, forest health specialist, Fitchburg. Michael.Hillstrom@wisconsin.gov; 608-513-7690

Invasive brown marmorated stink bugs (BMSB) are now well established and reproducing in southern and central Wisconsin. This fall we are getting our first reports of large numbers of BMSB gathering on the sides of houses looking for places to overwinter. This problem will continue to get worse as stink bug populations increase and their range expands. Damage to important crops, ornamental plants and trees will also be a major concern. BMSB is known to feed on a wide variety of plants including apples, tomatoes, corn, soybeans, silver maple and walnut.

Adult brown marmorated stink bugs are ½ to ¾ inch long, brown with alternating white and black patches on the edge of the abdomen and white bands on the antennae and have smooth shoulders that lack spines.

An adult brown marmorated stink bug. Photo by P.J. Liesch, University of Wisconsin Insect Diagnostic Lab.

Researchers are working on ways to manage the pesky bugs. One new method being explored is hanging black netting soaked in insecticide at locations where the bugs congregate, such as doors on the north and east sides of structures.

Samurai wasps are another promising lead. These stink bug-killing wasps found their way into the U.S. on their own over the past few years, but researchers are also working with lab-reared samurai wasps that they hope to release. Samurai wasps parasitize the eggs of BMSB but do not sting humans or other animals.

For more information about identification and management check out:
• University of Wisconsin-Extension
• WisContext
• Midwest Stink Bug app

EAB biological control recoveries

Posted on by Ellen Clark

By Bill McNee, forest health specialist, Oshkosh. bill.mcnee@wisconsin.gov; 920-360-0942

Tetrastichus planipennisi, an introduced, parasitic wasp that attacks emerald ash borer (EAB) larvae, was successfully recovered at two sites in Racine and Waukesha counties in October 2018. This was the first recovery of the natural enemy from Waukesha County. These events indicate that the wasps, released at the same sites in 2015, successfully established and have been attacking EAB larvae since then. This wasp species was previously recovered at release sites in six southeast Wisconsin counties (Kenosha, Milwaukee, Ozaukee, Racine, Walworth and Washington). These releases began in 2011 to reduce EAB populations over the long term, so that some small ash trees might reach reproductive maturity, thus allowing ash to persist on the landscape, albeit as a smaller, less common tree. The tiny wasps do not sting or bite people, and the public is unlikely to ever see them.

Adult Tetrastichus planipennisi wasp shown on a finger. Photo by Bill McNee.

Tree bark samples from the two sites are currently being incubated to look for another parasitic wasp, Oobius agrili, that may be present in EAB eggs. This species has not been recovered in prior surveys and is known to be more difficult to detect than T. planipennisi. Recovery surveys will continue at many locations 2-3 years after wasps are released to allow the populations of introduced parasitoids to increase to detectable levels.

It is important to note that insecticide treatment of high-value ornamental trees still needs to be done to prevent tree mortality from EAB. For more information about EAB, parasitoid wasps, and insecticide treatments, visit http://www.emeraldashborer.wi.gov.

Cluster of Tetrastichus pupae (circled) from a parasitized EAB larva, located near an unparasitized EAB larva. Photo by Bill McNee in Racine County, October 2018.

New forest health specialist for Central Zone

Posted on by Ellen Clark
New forest health specialist Alex Feltmeyer in woods.

New forest health specialist Alex Feltmeyer. Photo by Mike Hillstrom.

Alexandra (Alex) Feltmeyer started October 15, 2018 as the Forest Health Specialist for the Central Zone (Adams, Green Lake, Lincoln, Marathon, Marquette, Menominee, Oconto, Portage, Shawano, Taylor, Waupaca, Waushara, and Wood counties). Alex will be stationed at the Plover Ranger Station and will start making connections with the foresters and partners in her zone right away. Her contact information is Alexandra.Feltmeyer@wisconsin.gov and 715-340-3810.

As a reminder, the DNR forest health specialists are available to diagnose and provide management recommendations for forest health concerns such as insect, disease and weather-related damage on forested properties in Wisconsin. The forest health specialists are also available to give presentations and trainings on current insect and disease concerns and management guidelines. For a full list of forest health program staff and the counties they cover, please visit https://dnr.wi.gov/topic/ForestHealth.

Reduce crime and violence with trees in your neighborhood

Posted on by Ellen Clark

Can trees reduce aggression, violence and crime? Multiple studies say, “Yes!” October is domestic violence awareness month. Let trees be part of the solution. Levels of aggression and violence have been shown to be significantly lower among individuals who have some nearby nature outside their apartments than among their counterparts who live in barren conditions. Surveys exploring these results show residents with green views report using reasoning more often in conflicts with their children rather than violence. They also report less use of physical violence in conflicts with partners compared to those living in buildings without trees. Continue reading “Reduce crime and violence with trees in your neighborhood” →

Celebrate your neighborhood trees this month

Posted on by Ellen Clark

As the leaves begin to change from green to shades of orange, yellow and red, we celebrate the benefits these steadfast neighbors provide. October is NeighborWoods® Month, a campaign to plant and care for community trees. “Each year, tens of thousands of volunteers act to make their communities greener and healthier by planting trees – keeping their neighborhoods vibrant,” the Arbor Day Foundation reports.

Continue reading “Celebrate your neighborhood trees this month” →

Public comment period for HRD treatment guidelines revision closes October 16

Posted on by jodieellis

A fruiting body of Heterobasidion irregulare at the base of a pine tree.

By Kyoko Scanlon, forest pathologist, Fitchburg. Kyoko.Scanlon@wisconsin.gov; 608-235-7532

Wisconsin DNR is seeking public comments on a proposed revision to preventative treatment guidelines for Heterobasidion root disease (HRD). Stand-level HRD treatment guidelines were originally released in 2013. A DNR technical team and stakeholder advisory committee proposed a revised version using recent research findings, operational experience, and economic considerations.

The draft document and information about the public comment process can be found at  https://dnr.wi.gov/news/input/Guidance.html#open through Tuesday, October 16, 2018. All comments must be submitted by that date.

Leaf-browning on white and burr oaks

Posted on by jodieellis

By Mike Hillstrom, forest health specialist, Fitchburg. Michael.Hillstrom@wisconsin.gov; 608-513-7690

Dying leaves on white oak. Photo: Mike Hillstrom.

Dying leaves on white oak. Photo: Mike Hillstrom.

During late August and September of this year, Forest Health staff received several comments about problems with white and burr oaks. Leaves on affected trees turned brown, curled and died prematurely. Some trees were almost completely affected, while others only mildly. Symptoms varied widely between trees, even between those located next to each other. After examining several samples, the DNR Forest Health Lab concluded that damage was likely caused by fungal leaf pathogens and the twig canker fungus Botryosphaeria. Because the damage occurred late in the growing season, afflicted trees will not likely suffer major impacts. Although Botryosphaeria can cause twig dieback, oak trees usually recover without long-term problems. Continue reading “Leaf-browning on white and burr oaks” →

Return of Asian multicolored ladybugs

Posted on by jodieellis

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 920-360-0665

Multicolored Asian ladybeetles, true to their name, come in a range of colors, from orange to red, with a variety of spot sizes and numbers.

Multicolored Asian ladybeetles, true to their name, come in a range of colors, from orange to red, with a variety of spot sizes and numbers. Photo: Linda Williams

Multicolored Asian ladybeetles are not native to Wisconsin. Although there are numerous native ladybugs in the state, only the Asian variety are known to aggregate in buildings in the fall and become nuisances. Continue reading “Return of Asian multicolored ladybugs” →

Pine root collar weevil

Posted on by jodieellis

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 920-360-0665

This jack pine is leaning due to damage at its base from pine root collar weevil. Photo: Linda Williams

This jack pine is leaning due to damage at its base from pine root collar weevil. Photo: Linda Williams

Damage from pine root collar weevils was recently reported in Lincoln, Marinette, and Vilas counties on jack pine trees. Pine root collar weevils are known to attack and kill all types of pines, although scotch, red, and jack pine are the most common hosts in Wisconsin. The insects attack pine trees of varying sizes – from large saplings to those of small pole size. Adult weevils deposit eggs at the tree’s base; larvae then bore under bark and feed in the root collar area, effectively girdling the tree. Soil and bark near the root collar becomes blackened and soaked with pitch. Feeding larvae are visible in tunnels under the bark. Continue reading “Pine root collar weevil” →

Oak branch tips laying on the ground this fall

Posted on by jodieellis

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 920-360-0665

An oak branch tip clipped by a squirrel and dropped to the ground. Photo: Linda Williams

An oak branch tip clipped by a squirrel and dropped to the ground. Photo: Linda Williams

Forest health specialists in the northern part of the state recently received reports of oak trees suddenly losing branch tips (complete with attached leaves). Preliminary examinations of cut/branches did not initially reveal any obvious problems. However, upon closer inspection, teeth marks from squirrels were found on many of them. Squirrels were even observed clipping oak branches and dropping them to the ground. Continue reading “Oak branch tips laying on the ground this fall” →