Statewide Forest Health

Tree decline and mortality observed at many wet sites this summer

By Bill McNee, DNR Forest Health Specialist, Oshkosh. bill.mcnee@wisconsin.gov; 920-360-0942

An aerial view of tree mortality in very wet areas. Photo: Bill McNee

An aerial view of tree mortality in very wet areas. Photo: Bill McNee

Site visits and aerial surveys conducted on trees in eastern Wisconsin by the Wisconsin DNR forest health team in July and August found multi-species decline and mortality common at many very wet sites. Continue reading “Tree decline and mortality observed at many wet sites this summer”

Oak leaf fold galls and itch mites

by Mike Hillstrom, forest health specialist (Fitchburg). Michael.Hillstrom@wisconsin.gov;
208-513-7690

Oak leaf fold galls on red oak leaves. Photo: Mike Hillstrom

Oak leaf fold galls on red oak leaves. Photo: Mike Hillstrom

Ethan Lee, parks supervisor for the City of Janesville, recently reported symptoms of oak leaf fold galls on an oak tree on the University of Wisconsin – Rock County campus. Oak leaf fold galls, caused by fly larvae, are generally harmless to trees. However, new information links oak leaf galls with a recent invasive mite from Europe, Pyemotes herfsi, commonly called the oak leaf itch mite. Although no evidence of itch mite was found on the affected red oak tree, more than 50% of the tree’s leaves contained leaf fold galls. Continue reading “Oak leaf fold galls and itch mites”

Be on the lookout for beech leaf disease

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

Early striping from BLD as seen looking up into the canopy. Photo: The Ohio State University.

Early striping from BLD as seen looking up into the canopy. Photo: The Ohio State University.

Although beech leaf disease (BLD) has not been found in Wisconsin, forest owners and managers should keep an eye out for it on American (Fagus grandifolia) and, to a lesser extent, European (Fagus sylvatica) beech trees. Beech leaf disease is becoming a serious issue in parts of Ohio, Pennsylvania, New York and Ontario. Its cause is not yet known.

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Balsam fir mortality in many counties around the state

Counties shaded in blue are where balsam mortality has been reported, but the is even more widespread than this map indicates.

Counties shaded in blue are where balsam mortality has been reported, but it is even more widespread than this map indicates.

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

Reports of balsam fir suddenly turning rusty red to brown and dying have been coming in steadily this spring and summer. The accompanying map shows where this has been reported so far this year.

Spoiler alert! There are no insect or diseases involved. It appears the cause may be unusually severe winter drying or winter damage.

Continue reading “Balsam fir mortality in many counties around the state”

Fall webworms start making an appearance

By Todd Lanigan, forest health specialist, Eau Claire, WI. Todd.Lanigan@wisconsin.gov; 715-210-0150

A silken nest full of caterpillars, excrement and debris. Photo: Todd Lanigan

A silken nest full of caterpillars, excrement and debris. Photo: Todd Lanigan

Web-like nests of fall webworm (Hyphantrea cunea) caterpillars, a common native pest active from July through September, are beginning to appear in parts of the state. A common native pest throughout most of the U.S. and southern Canada, fall webworm caterpillars feed on leaves of almost all shade, fruit, and ornamental trees and shrubs, except for conifers. They typically form nests of loose webbing over the tips of tree branches.  Although populations of fall webworm caterpillars are rarely large enough to cause lasting damage to trees, the presence of nests and feeding damage from caterpillars can greatly affect trees’ aesthetic value. Typically, trees recover from feeding damage on their own, but defoliation for more than two or three years in a row could make trees more susceptible to diseases and pests.

Continue reading “Fall webworms start making an appearance”

Forest Health Program welcomes new forest invasive plant coordinator

By Jodie Ellis, communications specialist, Madison. Jodie.Ellis@wisconsin.gov; 608-843-3506

Michael Putnam

Michael Putnam, DNR Forestry’s new forest invasive plant coordinator.

The Forest Health Program is excited to welcome Mike Putnam as its new forest invasive plant coordinator. Mike has been working with the program as an LTE for more than four years in Madison; his new position is in Rhinelander. He’ll be focusing on invasive plants prevention and management with DNR foresters and partners, so please reach out to him with field work opportunities.

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White pine bast scale and fungus

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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Forestry partners take lead in 2018 EAB trapping

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

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”

Trapping for non-native beetles

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.