Pest Alert: Watch for Winter Moth Damage (April 30, 2007)

Now is the time to begin scouting for winter moth damage on your plants. UMass Extension reports winter moth larvae are hatching and feeding in expanding buds in southeastern MA. Known hosts of the winter moth include maple, oak, apple, crabapple, ash, cherry, and blueberry. Winter moth populations have been very high in coastal areas of Massachusetts from Gloucester to the South Shore and out onto Cape Cod and Martha's Vineyard. Winter moth has also been observed further inland in Massachusetts and established populations are present in Rhode Island. Winter moth has also been picked up in pheromone traps in southeastern NH, coastal Maine, southeastern CT and Long Island. Since winter moth is already established in eastern Massachusetts, please do not report it with the website’s on-line reporting system.

Young larvae will feed inside the buds of plants moving from bud to bud to feed. Once the buds open larvae will continue feeding on the expanded leaves until they drop to the soil in late May or early June to pupate. Winter moth caterpillars are a pale green “inchworm” with white stripes down both sides of their body. The winter moth will then be out of sight until adults emerge in late November or early December.

Resources on the winter moth:
Photos and information on identifying winter moth can be found on the Massachusetts Introduced Pests Outreach website http://www.massnrc.org/pests/pestFAQsheets/winter%20moth.html

UMass Extension Landscape, Nursery, and Urban Forestry program has posted updated winter moth information.
http://umassgreeninfo.org/fact_sheets/defoliators/wm_overview_07.pdf
“Identifying and Managing the Life Stages of the Winter Moth” has excellent information on control strategies and photos of winter moth.
http://www.umassgreeninfo.org/fact_sheets/defoliators/wm_id_man.html

The "Caterpillar update" will help you differentiate winter moth from other caterpillar problems.
http://www.umassgreeninfo.org/fact_sheets/defoliators/caterpillar_update_06.pdf.

The pest alert is from the Massachusetts Introduced Pests Outreach Project, a collaborative project between the Massachusetts Department of Agricultural Resources and the UMass Extension Agriculture and Landscape Program aimed at preventing the establishment of new pathogens and pests in Massachusetts. Visit the project website (http://www.massnrc.org/pests) for more information on emerging pests or to subscribe and unsubscribe for pest alerts.