Pest

New finds of emerald ash borer in Wisconsin

Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov, 715-356-5211 x232

Emerald ash borer (EAB) continues to be found in new areas in Wisconsin, where EAB is tracked at the municipality and township levels. Recently, the insect was found for the first time in Eau Claire County, and there were additional finds in Dane, Dodge and Door counties where EAB is already established.

ounties shaded in tan are quarantined for EAB; this includes much of the southern half of  Wisconsin as well as other counties. Areas shaded in green represent the townships and municipalities where EAB has actually been identified, and show that not all counties that are quarantined are fully infested.

EAB quarantine map: counties shaded in tan are quarantined for EAB, green areas within counties depict townships and municipalities where EAB has been confirmed.

 

 

 

How did the cold snap over Christmas and New Year’s affect insects?

Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov, 715-356-5211 x232

Are you wondering how the bitterly cold weather we had in Wisconsin over Christmas and New Year’s affected the insects in your area? You’ll probably be disappointed to learn that, in general, our forest pests handle cold snaps just fine. Here are some examples of what it would take to have an impact on some of our insect pests: 

Gypsy moth: Well, it depends. If egg masses were covered by snow (either near the ground or on branches), they were protected from the cold temperatures. If egg masses were exposed, according to a study done in Michigan, it would take several days of temperatures lower than -15 °F to start seeing mortality in eggs. The more days eggs spend below that temperature, the more mortality, although super-cooled eggs or eggs covered by snow can withstand much lower temperatures and survive. 

Forest tent caterpillar eggs form a band around an aspen twig. The protective hairs coating the eggs have been removed to show the eggs. Photo: Linda Williams

Forest tent caterpillar eggs form a band around an aspen twig. The protective hairs coating the eggs have been removed to show the eggs. Photo: Linda Williams

Forest tent caterpillar: This native insect enjoys our northern climes, so it should be no surprise that it handles the cold quite well. One study found that at temperatures below -45 °F, there was significant mortality. The egg masses of forest tent caterpillars are found near the tips of branches, which are not typically covered with snow. 

Spruce budworm: As with forest tent caterpillar, this native insect thrives in the cooler regions of North America and temperatures lower than -40 °F are required to see any mortality. 

Emerald ash borer: You may recall in 2014, when we also had bitterly cold temperatures, there was quite a media furor about EAB mortality and some research that was going on in Minnesota. Everyone was hoping EAB would be killed completely in those cold areas. Although some mortality did occur, researchers found that because EAB larvae and pre-pupae are protected under the bark of the tree, temperatures need to be drastically low, or very low for a certain number of days, to see significant mortality. That being said, EAB mortality can occur at temperatures below -13 °F, and, if enough mortality occurs, the spread of the population may be slowed as it has to rebuild from the few individuals that survived the bitter cold. 

Multicolored Asian ladybeetles cluster together in protected places to wait out the cold. 

Multicolored Asian ladybeetles cluster together in protected places to wait out the cold. Photo: Linda Williams

Household pests like ladybugs and flies:  Those kinds of insects find protected places to spend the winter (sometimes in your house!), and although there can be significant mortality outside, there will be many that survive the cold just fine.  They often find protected places that are slightly warmer than ambient air temperatures. 

Ticks:  Wood ticks and deer ticks overwinter on the ground, under snow, so in areas of the state where there is plenty of snow cover, they’re doing fine so far.  Desiccation is usually a much more important problem during the life of a tick than overwintering cold. 

Some insects seem to enjoy winter weather, like snowfleas (also known as collembolans or springtails), and winter cutworm, both of which can be found crawling on snow during warmer winter days. 

How can insects survive winter? Different types of insects overwinter during different life stages.  Some insects overwinter as eggs, because eggs are often quite resistant to desiccation, can have “hairs” covering them, are laid in protected areas, or inserted into needles/bark/etc. to give even more protection.  Some adult and larval insects survive winter by supercooling, which is a process in which they eliminate water molecules from their bodies (which, if left behind, could create deadly crystals in their systems).  Supercooling is the equivalent to using antifreeze, allowing the insects to survive very cold temperatures.  One problem insects can have is when there is a warm-up followed by a sudden cold snap, a situation which also causes problems for trees.  When we have steady cold temperatures, insects tend to just hang out like we do, waiting for spring.

 

 

 

 

 

National Invasive Species Awareness Week

Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov, 715-356-5211 x232

National Invasive Species Awareness Week (NISAW) was held from February 26 to March 2 this year. The annual event helps raise awareness and identify solutions to invasive species issues at local, state, tribal, regional, international and national scales. The event not only addresses insects and diseases, but all invasive species, including plants, reptiles, birds, and everything else. Visit the National Invasive Species website for things that you can do increase your awareness of invasive species, or click here to learn about ways you can help.

 

 

 

Comments sought re: change in gypsy moth rule

Aerial spraying of Btk for gypsy moths.

Aerial spraying for control of gypsy moths. Photo: John Ghent, bugwood.org

The WI DNR is proposing to deactivate the gypsy moth suppression program as requests for treatment have fallen to very low levels and this small need can be met by private businesses. The DNR is taking input on the proposed change to rule NR 47.910. If you have questions, concerns, or comments about this proposal you may give your input by attending a hearing or in writing. Input must be received on or before Tuesday, Dec. 19, 2017 to be considered.

Public hearings will be held on Dec. 19, at 11:00 a.m. at DNR service centers in Fitchburg, Milwaukee, Green Bay and Eau Claire. Input may be given verbally or in writing at the hearing.

Written comments may be submitted by U.S. mail, e-mail, or through the internet. Written comments will have the same weight and effect as oral statements presented at the public hearing.

E-mail comments may be made at: DNRAdministrativeRulesComments@wisconsin.gov (Please include “Attn: Andrea Diss-Torrance” in subject line.)

Written comments and any questions on the proposed rules should be submitted to:
Department of Natural Resources
Attn: Andrea Diss-Torrance
P.O. Box 7921
Madison, WI 53707-7921

Written by: Andrea Diss-Torrance, invasive forest insects program coordinator, Madison. Andrea.DissTorrance@wisconsin.gov; 608-264-9247

Gypsy moth numbers rising in northern WI

 

Fig 1. Average gypsy moth trap counts in northern Wisconsin counties. Map credit: Adapted, Slow The Spread Foundation, Inc.

Fig 1. Average gypsy moth trap counts in northern Wisconsin counties. Map adapted from the Slow The Spread Foundation, Inc.

Annual surveys conducted by the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) indicate gypsy moth populations have increased in several northern Wisconsin counties and by 20% statewide. High moth counts were detected in pheromone traps in Ashland, Bayfield, Burnett (Dewey Township), Iron, Oneida, and Vilas counties, with the highest overall count in Bayfield County (14,354 moths total).  Areas with an average catch per trap of 100 moths or more will likely experience damaging levels of defoliation by gypsy moth caterpillars in the following year or years (Fig. 1).

Defoliation can be reliably predicted at the stand level by counting gypsy moth egg masses from August through March before egg hatch; these estimates help determine if preventive measures, such as physical controls, insecticide treatments, or delaying thinning activities are needed until populations collapse. 

In recreational and residential high-use areas, physical controls such as sticky bands and burlap barriers may be used to help reduce nuisance and aesthetic impacts from gypsy moths.  Aerial treatments are used when gypsy moth populations are high. In managed forests, use of silvicultural techniques may be economically feasible to reduce productivity problems caused by the pest.

Learn more about prevention and management options for your property by consulting with your local DNR forester or regional forest health specialist.

More information about population sampling and management options is available online at www.gypsymoth.wi.gov.

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

Recent finds of emerald ash borer in WI

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.

  • none

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

Updated forest health fact sheet – conifer bark beetle

Spruce beetle (Dendroctonus rufipennis)

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

Jack pine budworm is a no-show in West Central WI this year

Jack pine budworm caterpillar on jack pine.

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.

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

 

 

Ladybugs, boxelder bugs and others that want to live in your house

Multicolored Asian ladybeetles search for places to spend the winter and often congregate in protected places.

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.

Western conifer seed bugs (sometimes called leaf footed bugs) on the left, and boxelder bugs on the right, also congregate in the fall as they look for warm protected places to spend the winter.

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

Six new counties quarantined for EAB

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.

Wisconsin counties quarantined for EAB (WI DATCP)

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.

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