Insect

Defoliation by June beetles

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

June beetles defoliating an oak sapling at night.

June beetles defoliating an oak sapling at night.

June beetles (also called May beetles) are defoliating oak, aspen and birch trees in several parts of Wisconsin this spring. These beetles are unusual in that they feed on foliage at night – look for defoliation during daytime hours although no insects are present. Although the highest densities of June beetles have been found in Crawford and Grant counties in southwest Wisconsin, forest health staff has also received reports of the insect from northeast and west central Wisconsin. Continue reading “Defoliation by June beetles” →

Forestry partners take lead in 2018 EAB trapping

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

As summer approaches, adult emerald ash borer (EAB) beetles are beginning to emerge to feed and reproduce.

Areas of possible initial EAB emergence.

USDA APHIS EAB emergence map. Map credit: USDA Cooperative Emerald Ash Borer Project

Due to the recent statewide quarantine for emerald ash borer and workload considerations, USDA’s Animal and Plant Health Inspection Service, Plant Protection and Quarantine (APHIS PPQ), the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), and the Wisconsin DNR Forest Health Program have discontinued trapping programs for adult beetles in Wisconsin. Continue reading “Forestry partners take lead in 2018 EAB trapping” →

Eastern tent caterpillar and control options

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

Young eastern tent caterpillars on their web nest. Photo: Linda Williams

Young eastern tent caterpillars on their web nest. Photo: Linda Williams

Winter is finally over and eastern tent caterpillars are hatching and building their web nests! In northern Wisconsin, the caterpillars began hatching in early to mid-May, but they emerged earlier in southern Wisconsin. Webs will become larger as the caterpillars feed and grow. Continue reading “Eastern tent caterpillar and control options” →

Forest tent caterpillar: surveys, prediction, and history

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

Areas in northern Wisconsin with forest tent caterpillar defoliation during the peak year of most recent regionwide outbreak, from 1999 – 2002

Forest tent caterpillar larvae feeding on ash foliage. Photo: Paul Cigan

Late-winter surveys in northern Wisconsin for egg masses of forest tent caterpillars (FTC) suggest that numbers will remain low through 2018, continuing a 15-year trend, one of the longest documented intervals between FTC outbreaks in the state. Continue reading “Forest tent caterpillar: surveys, prediction, and history” →

Trapping for non-native beetles

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

A Lindgren funnel trap hung to collect beetles near Green Bay, WI. Photo: Mike Hillstrom

Scott Schumacher, an insect trapper for the Wisconsin DNR’s forest health team, will spend this summer hunting for non-native beetles using funds provided by the U.S. Forest Service. The survey is particularly focused on non-native bark and ambrosia beetles, which are potentially harmful to Wisconsin forests. In early May, Schumacher hung Lindgren funnel traps at 12 sites in Wisconsin which he will be checking throughout the season. Traps were placed at high-risk sites in wooded areas near large commercial port entries on Lake Michigan and near pallet and other waste-packaging recycling companies. Although preventing the arrival of non-native species is always top priority, early detection and rapid response (EDRR) to newly-detected infestations is an important strategy to protect forests from damaging invaders.

Ladybugs in your house this spring?

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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” →

White pine weevil – old and new damage

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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” →

EAB biocontrol releases continue in 2018

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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.

Historical Forest Health News – 1993 and 1968

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News from 25 years ago (1993)

Jack pine budworm – Choristoneura pinus (Rohwer)

Area of defoliation by jack pine budworm in 1993 shaded in black.

Area of defoliation by jack pine budworm in 1993 shaded in black.

“This defoliator erupted in northern and central Wisconsin to cause moderate to heavy defoliation on 400,000 acres of jack pine. This was the second year of defoliation in Clark, Eau Claire and Jackson counties, and first year defoliation in Monroe County. The largest areas of defoliation were in the northwest where periodic outbreaks are expected. Heavy defoliation occurred in Adams, Juneau, Wood, Clark, Eau Claire, Jackson and Monroe counties. Light feeding was apparent in the Conover area of Vilas county. In Oconto county a 90-acre planting of sapling white pine suffered heavy terminal and upper lateral defoliation. Spotty light to moderate defoliation occurred in Oconto and Marinette counties in the northeast. Defoliation in Marinette county was heaviest in over-mature natural stands of jack pine stands in Silver Cliff Township (Sections 22, 23, 27, 26, 34, 35, T34N, RISE).

In Juneau and Wood counties, tree mortality is expected to be high because many trees lost 90 to 100 percent of their foliage. Salvage harvests were scheduled in the defoliated stands that were predicted to suffer heavy mortality. Some of the harvests in the central and westcentral counties were in potential conflict with the protection of the Karner blue butterfly, a newly listed endangered species. Guidelines were developed to survey for the Karner Blue and for its food plant, blue lupine. The guidelines also contain procedures to prevent damage to known Karner Blue habitat during harvest operations. Many defoliated stands that were scheduled for salvage harvests were surveyed. Late season egg mass surveys revealed a 33% decline from 1992 levels in the northwestern counties portending a decrease in populations and defoliation in 1994. In western and central Wisconsin, the egg mass surveys indicate the budworm populations should remain high in 1994. Egg mass surveys in Wood County averaged 5.8 egg masses per plot. Egg mass surveys in Marinette county indicate defoliation will likely be spotty and variable in intensity again in 1994.”

Continue reading “Historical Forest Health News – 1993 and 1968” →