Pest Alert: Winter Moth Flight in eastern MA (November 27, 2006)

Winter moth flight in eastern Massachusetts has begun. Winter moth flight typically begins around Thanksgiving and continues into December or possibly January if air temperatures are warm enough. Male winter moths are small, light brown moths that are attracted to lights at night. The female moths are flightless due to greatly reduced wings. They are often found climbing on tree trunks where they will lay eggs in bark cracks and crevices. The eggs survive the winter and caterpillars hatch from them anytime from late March into April. Winter moth caterpillars will feed on many plant species including maple, oak, apple, crabapple, ash, cherry, and blueberry. No effective control methods are available for adult moths. The UMass Extension fact sheet on winter moth gives information about controlling the moth in the egg stage with dormant oil or in the larval stage with Bt or chemical insecticides.
Winter moth populations have been very high in coastal areas of Massachusetts from Gloucester to the South Shore and out onto Cape Cod. Surveys conducted in 2005 found winter moth as far west as Worcester and all the way to the New Hampshire border. Winter moth has been confirmed in 9 counties in Massachusetts (Essex, Middlesex, Suffolk, Norfolk, Plymouth, Bristol, Barnstable, Dukes, and Worcester). Winter moth is also established in Rhode Island and has been found in eastern Connecticut. Since winter moth is already established in eastern Massachusetts, please do not report it with the website’s on-line reporting system.

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 excellent information on control strategies and photos of winter moth.
“Identifying and Managing the Life Stages of the Winter Moth”
http://www.umassgreeninfo.org/fact_sheets/defoliators/wm_id_man.html

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.