Pest

Ladybugs in your house this spring?

Posted on by jodieellis

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232

One option for removal of ladybugs from your home is to flick them into a small container containing soapy water, which will kill them.

One option for removal of ladybugs from your home is to flick them into a small container containing soapy water, which will kill them. Photo: Linda Williams

In the December 2017 edition of Forest Health News, I wrote about ladybugs congregating in or on homes during autumn. Now that winter has finally ended in Wisconsin, ladybugs that spent winter in the walls of your house are emerging, and many of those will accidentally emerge into, not out of, your home. This can create panic or aggravation, depending on you (or your spouse’s) tolerance for insects in the house. Continue reading “Ladybugs in your house this spring?” →

Defoliation by larch casebearers

Posted on by jodieellis

By Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232

The two cigar-shaped, tan objects sticking to the newly expanding needles of this tamarack tree are larch casebearer caterpillars, feeding on the foliage.

The two cigar-shaped, tan objects sticking to the newly expanding needles of this tamarack tree are larch casebearer caterpillars, feeding on the foliage. Photo: Linda Williams

As tamarack needles begin to appear, so do some tiny caterpillars that feed on them. Larch casebearers defoliate tamarack trees early in the season, first causing the trees to look pale green or yellowish, or even brown if defoliation is severe. This year I have been able to find larch casebearers wherever I look, but so far, I haven’t found any high populations of the insect. Continue reading “Defoliation by larch casebearers” →

Region-wide needle tip browning on red pine

Posted on by jodieellis
Typical appearance of needle tip browning on lower portion of red pine crowns

Red pine with needle tip browning on the lower crown. Photo: Paul Cigan

By Paul Cigan, forest health specialist, Hayward.  Paul.Cigan@wisconsin.gov; 715-416-4920

Although no tree mortality is associated with the condition, widespread needle tip browning on red pine has been observed for the second consecutive year across much of the upper Great Lakes region. The condition is heavier in some places than others, but once in a stand or location, tends to be evenly distributed. Needle tip browning is common on the lower half of mature red pine crowns. On two- to three-year-old needles, the outer half to three-quarters of the needles appear reddish brown to straw-colored while needle bases remain green. Black or dark brown necrotic bands and spots are often present on symptomatic needle tips. Lower crown thinning is also common on symptomatic pine. Newly impacted needles will gradually lighten in color from reddish brown to straw-colored as dead needle tips dry out through the growing season. Continue reading “Region-wide needle tip browning on red pine” →

New “Tick App” available

Posted on by jodieellis
Ticks pose increasing health threats throughout North America

Ticks pose increasing health threats throughout North America. Photo: WI DNR

from the May 2018 edition of RECReport, for the WI DNR Bureau of Parks and Recreation Management

The University of Wisconsin-Madison, a partner in the Midwest Center of Excellence (Center) in Vector-Borne Diseases, has announced that “Tick App” is now available for download. Tick App is a phone application that is part research tool and part educational tool with the goal to transition towards a preventative tool over time.

The Center would like to enroll people, by the app, in their study to determine the risk for tick encounters, assess the success/failure of self-reported prevention strategies, and educate people at the same time. Participation is entirely voluntary. When people download the app, they will go through a sign-up process—and about 5 minutes of questions—so the researchers can assess risk factors for tick exposure.

When people are in the app they can complete daily tick diaries (asking about activities and tick exposure) and can report a tick. Users can even send in an image for identification after the report is completed. For more information on the Tick App, visit http://www.thetickapp.org or tickapp@wisc.edu.

White pine weevil – old and new damage

Posted on by jodieellis

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232

The terminal leader of this young white pine was killed by white pine weevil.

The terminal leader of this young white pine was killed by white pine weevil. Photo: Linda Williams

White pine weevil is an insect that can attack and kill the terminal leader on white pine, jack pine, and spruce trees. Terminal leaders killed last year may remain on the tree until spring, although they commonly break off during winter. Adult weevils are now out laying eggs on terminal leaders, just below the expanding buds. After the eggs hatch, the larvae will bore just under the bark of the terminal and feed, moving downward as they progress. As buds expand this spring, they will quickly run out of water and food due to damage caused by larval feeding, and the terminal leader will begin to wilt, curl, and die. Continue reading “White pine weevil – old and new damage” →

Figure out when your trees will bloom

Posted on by Kirsten Held

The Morton Arboretum is releasing information monthly on growing degree days. Plants, insects and fungi all develop at various times depending on temperature. Development will speed up or slow down depending on the rise and fall of temperature. Several studies have worked to understand the relationship between heat and development. These studies and information from them help anticipate flowering of trees and shrubs and the emergence of insects based on how many growing days have accumulated. Continue reading “Figure out when your trees will bloom” →

Porcupine and squirrel damage on trees

Posted on by jodieellis

By Linda Williams, forest health specialist (Woodruff). Linda.Williams@wisconsin.gov; 715-356-5211, x232

During winter and early spring, damage to trees caused by porcupines and squirrels is evident in some areas. As spring arrives, new green leaves will mask the destruction.

This red pine had the bark stripped off it by a porcupine, which has wider incisors than a squirrel.

This red pine had the bark stripped off it by a porcupine, which has wider incisors than a squirrel.

Porcupine and squirrels feed on the bark of trees, stripping it from branches and main stems. Stripping bark can girdle trees, resulting in branch dieback which shows up the year following the damage. If the branch isn’t completely girdled, it will start to grow callus tissue over damaged areas in an attempt to recover.

This maple bark was eaten by a squirrel. You can see where the tiny incisors scraped the bark down to the wood.

This maple bark was eaten by a squirrel. You can see where the tiny incisors scraped the bark down to the wood.

Both porcupines and squirrels feed on bark in the crowns of trees, so how can you tell which one is doing the damage if you don’t catch them in the act? The size of the teeth marks left in the wood is one clue. A gray squirrel’s incisors leave marks between 1.3 to 1.7 mm wide, while a porcupine’s teeth marks are nearly triple that, from 3.6 to 4.8 mm wide. You should also consider the species of tree being debarked: squirrels prefer maples while porcupines will feed on oak, pine, maple, and even spruce, as well as other species.

Rabbits, mice, and voles can cause similar damage to that caused by squirrels and porcupines, but damage will be located near the base of the tree instead of in the crown.

Another type of tree damage seen in late spring is when squirrels clip 4 to 6 inches off the tips of spruce branches, apparently to consume tasty buds. They drop the remainder of the branches to the forest floor, leaving a carpet of branch tips under spruce trees. I have yet to observe squirrels doing this, but the carpet of branch tips they leave prompts calls from concerned landowners each spring.

Spruce branch tips litter the ground where squirrels dropped them after clipping them from the tree. Although it can look alarming it rarely does enough damage to affect the overall health of the tree.

Spruce branch tips litter the ground where squirrels dropped them after clipping them from the tree. Although it can look alarming it rarely does enough damage to affect the overall health of the tree.

UW Extension offers a brochure about squirrels, including control options to share with landowners having trouble with these critters.

EAB biocontrol releases continue in 2018

Posted on by jodieellis

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

In 2018, the Wisconsin DNR will complete its eighth year of releasing tiny, stingless wasps as biocontrol agents to help manage emerald ash borer. Columbia, Dane and Grant counties are slated for first-time releases this year, and there will be new release sites in Brown, Door and Sheboygan counties. The wasps will be released for a second year at established sites in Brown, Green, Jefferson, Milwaukee and Sheboygan counties. The same wasps that were released in 2017 will be used this year: Tetra sticus planipennisi, Spathius galinae and Oobius agrili.

Tiny adult Spathius galinae wasps are released near an infested ash tree where they will look for EAB larvae to parasitize

Adult Spathius galinae wasps venture out to find some tasty EAB larvae to parasitize.

 

Map showing the numerous biocontrol sites for emerald ash borer established in southern and eastern Wisconsin since 2011.

Biological control sites for emerald ash borer in Wisconsin 2011-2018. Figure by Bill McNee.

Statewide quarantine for emerald ash borer

Posted on by jodieellis

By Jodie Ellis, DNR Forest Health Team, communications specialist (Madison), Jodie.Ellis@wisconsin.gov, 608-266-2172

An adult emerald ash borer.

An adult emerald ash borer.
Photo: Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) enacted a statewide quarantine for the invasive insect emerald ash borer  (EAB) on March 30, 2018. Previously, individual counties were quarantined when EAB was confirmed within each’s borders. Since EAB has been found in 48 of 72 Wisconsin counties, DATCP officials have determined that statewide regulation of the devastating ash tree pest is warranted.

Movement of ash wood, untreated ash products and hardwood firewood of any type to areas outside of Wisconsin will continue to be regulated by USDA’s Animal and Plant Health Inspection Service, Plant Protection and Quarantine. (APHIS PPQ). 

Within the state, Wisconsin businesses and members of the public will be able to freely move ash wood, ash products, and hardwood firewood to or from any Wisconsin county. Firewood restrictions will remain in effect on state and federal lands.

Items affected by the statewide EAB quarantine include ash wood with bark attached, larger ash wood chips, and hardwood firewood of any kind. County-by-county quarantines for gypsy moth, another invasive forest pest, remain in effect.  

The move to a statewide quarantine does not mean that the state has given up on managing EAB; it is simply a shift in strategy as EAB continues its slow spread through the state. The Wisconsin DNR will continue releasing tiny, stingless wasps -natural enemies of EAB – at appropriate sites, which it has done since 2011. The DNR also continues participation in silvicultural trials in which different ash management strategies are being tested.

Most importantly, campers, tourists, and other members of the public are strongly encouraged to continue taking care when moving firewood within the state. “The actions taken by the Wisconsin public during the last few years have significantly slowed the spread of emerald ash borer and other invasive forest pests in the state,” said Wisconsin DNR EAB program manager Andrea Diss-Torrance. “We can continue to protect the numerous areas within our state that are not yet infested – including those in our own backyards – from tree-killing pests and diseases by following precautions.” Public members should continue to obtain firewood near campgrounds or cabins where they intend to burn it, or buy firewood that bears the DATCP-certified mark, meaning it has been properly seasoned or heat-treated to kill pests.

Emerald ash borer is native to China and probably entered the United States on packing material, showing up first in Michigan in 2002. It was first found in eastern Wisconsin in 2008.

For further information on EAB in Wisconsin, visit https://dnr.wi.gov/ using key words “emerald ash borer.”

Prepare for the return of gypsy moths

Posted on by jodieellis

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

In a few weeks, gypsy moth egg masses will begin hatching in Wisconsin. Property owners interested in reducing gypsy moth populations should consider oiling or removing reachable egg masses well before the hatch begins. Horticultural oils that suffocate the eggs are available at many garden centers and large retailers. In general, these are applied when temperatures are above 40oF and freezing is not imminent. When physically removing egg masses, scrape them into a can of soapy water and then let them soak for a few days before discarding in the trash in order to kill the eggs. Additional management options for homeowners and woodlot owners are available at the Wisconsin gypsy moth website. 

Gypsy moth egg masses

Gypsy moth egg masses

Property owners looking to hire a business to do insecticide treatments this spring should contact them soon. A list of certified arborists is available on the Wisconsin Arborist Association website. Additional businesses offering insecticide treatments may be found in the phone book under ‘Tree Service.’ Homeowners can also purchase insecticides, some of which are applied as soil drenches, at garden centers and large retailers. For larger areas, a list of for-hire aerial applicators is available on the Wisconsin gypsy moth website.

Although this winter’s cold temperatures in late December and early January most likely did not cause heavy egg mortality, the cold period will still help reduce gypsy moth populations this summer. According to the U.S. Forest Service, temperatures of -20°F lasting from 48 to 72 hours can kill exposed eggs. Eggs that are laid higher up on the bark of trees suffer higher mortality than those located near the ground because snow insulates the eggs from cold temperatures. Fluctuating spring temperatures can also cause heavy egg mortality.

2018 suppression spraying:

Dane County will be the only participant in the DNR gypsy moth suppression program in 2018. Aerial spraying will occur in mid- to late May at seven sites in Madison and one site in Sun Prairie. A total of 485 acres will be sprayed with a bacterial insecticide that affects only small caterpillars. Maps of the sites are available on the Wisconsin gypsy moth website.

Slow-The-Spread treatments announced:

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) announced its planned 2018 Slow-The-Spread (STS) gypsy moth treatments in western counties. About 90,000 acres are scheduled for treatment at 36 sites in 14 counties, using low-flying airplanes. Treatments will begin in May and continue through late July or early August, using either bacterial insecticide or pheromones which cause mating disruption.

Map of proposed 2018 gypsy moth aerial treatments.

Proposed 2018 gypsy moth treatments will occur in these counties. Counties in yellow are scheduled for Slow-The-Spread (STS) treatments, while Dane County (in blue) will undergo a suppression spray.

Counties scheduled to receive aerial treatments are: Barron (3 sites covering 2,736 acres); Bayfield (1 site, 787 acres); Buffalo (6 sites, 11,754 acres); Burnett (2 sites, 4,529 acres); Chippewa (4 sites, 12,794 acres); Crawford (4 sites, 5,971 acres); Douglas (1 site, 789 acres); Dunn (5 sites, 43,986 acres); Eau Claire (1 site, 674 acres); Grant (1 site, 497 acres); Green (1 site, 392 acres); Lafayette (2 sites, 527 acres); Rusk (1 site, 463 acres); and Vernon (3 sites, 3,785 acres).

More information on STS treatments may be found online at the DATCP Gypsy Moth website.