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Rose chafer and Japanese beetle populations high in parts of state

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By Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 920-360-0665 and Todd Lanigan, forest health specialist, Eau Claire (Todd.Lanigan@wisconsin.gov), 715-210-0150

Rose chafer adults defoliate many different plants, shrubs, and trees. Photo: Linda Williams

So far this summer, only a few reports of significant defoliation and damage by rose chafers (Macrodactylus subspinosus) and Japanese beetles (Popillia japonica) have been submitted to the state’s DNR forest health specialists. Both of these leaf-skeletonizing beetles feed on foliage of many species of trees, shrubs and other plants. Although activity by Japanese beetles appears light this year, defoliation by rose chafers was reported in Marinette, Shawano, Waupaca, and Trempealeau counties.

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Defoliation by spruce budworm low to moderate in NE Wisconsin

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By Linda Williams, forest health specialist, Woodruff, Linda.Williams@wisconsin.gov, 920-360-0665 and Paul Cigan, forest health specialist, Hayward, Paul.Cigan@wisconsin.gov, 715-416-4920.

Severely defoliated balsam fir in Vilas County.

Severely defoliated balsam fir in Vilas County.

In many areas this summer, damage from spruce budworm (Choristoneura spp.), a native insect, is less noticeable than in past years. Although heavy defoliation is evident north of St. Germain in Vilas County and at a site in Shawano County, only light to moderate defoliation has been seen in other areas. Light defoliation was observed in Bayfield, Florence, Forest, Marinette, Oneida, Shawano, and Vilas counties. Defoliation was less predominant last year as well, probably because of unusually heavy rainfall in spring 2017 which led to an increase in tree growth. This year’s spring was also unusually wet, resulting in increased tree growth.

Spruce budworm outbreaks typically last about 10 years; the current outbreak began in 2012. The last two years of exceptionally robust tree growth may help some of the damaged trees to at least partially recover. Since 2012, some areas of northeastern Wisconsin experienced three or four years of heavy defoliation; affected trees are either dead or declining despite good growing conditions.

White pine bast scale and fungus

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

Branches in the mid- and lower-crown of this white pine are being killed by white pine bast scale and a fungal disease.

Branches in the mid- and lower-crown of this white pine are being killed by white pine bast scale and a fungal disease. Photo: Linda Williams

White pine bast scale and canker fungus has been identified in two sites in Oneida County. This insect/fungus complex is a new issue in the state; those who work with white pine should be alert for signs and symptoms.

White pine bast scale, a native scale, is tiny, black, oval-shaped, and lacks both eyes and legs. It uses a long stylet to siphon sap from outer layers of phloem (bast) of twigs and branches. White pine bast scales live under lichens on white pine branches. Although lichens don’t directly harm trees, they provide shelter for scale insects.

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Sparse-leafed elms and maples

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Heavy seed production by a red maple. The Ohio State University.

Heavy seed production by a red maple. The Ohio State University.

By Todd Lanigan, forest health specialist, Eau Claire. todd.lanigan@wisconsin.gov, 715-210-0150 and Paul Cigan, forest health specialist, Hayword. Paul.Cigan@wisconsin.gov, 715-416-4920

There have been reports that some elm and maple trees in the state have fewer leaves than normal this spring. The likely reason is that several elms and maples produced an unusually large amount of seed this year, which trees do periodically. During a heavy seed production years, the tree will produce fewer leaves, which may make it appear sparse. Continue reading “Sparse-leafed elms and maples” →

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?” →