Landscape_ Winter Moth in Massachusetts_ History and Biological Control _ Center for Agriculture, Food, and the Environment at UMass Amherst

Winter Moth in Massachusetts

• Scientific Classification

  • Common Name: Winter Moth

  • Scientific Name: Operophtera brumata

  • Order: Lepidoptera

  • Family: Geometridae

Historical Context

• Initial Outbreaks

  • First noticed in late 1990s on Cape Anne (North Shore) and Cohasset, Hingham, and Rockland (South Shore).

  • Initially thought to be caused by native species (like fall cankerworm).

  • Continued outbreaks and adult flights in December indicated it was likely winter moth, a European species.

  • Confirmed as winter moth by David Wagner (UConn) and Richard Hoebeke (Cornell) in 2003.

• Spread of Outbreak

  • Defoliation spread over the North Shore to Boston suburbs, Capitol City, Cape Cod, Martha’s Vineyard, and Rhode Island (Elkinton et al. 2014).

  • Caterpillar larval stage defoliates many deciduous trees: maples, oaks, apples.

  • 2005-2007 survey by Dr. Joseph Elkinton using pheromone traps defined the distribution from Long Island across New England into Canada.

  • Trap data indicated correlation between warmer winters and winter moth distribution adhering to USDA cold hardiness zones.

• Bruce Spanworm Presence

  • Pheromone traps also captured Bruce spanworm (Operophtera bruceata), a native species.

  • Unlike winter moth, Bruce spanworm is not an outbreak species but feeds on similar host trees.

Ongoing Research

• Factors Limiting Outbreaks

  • Research delving into reasons winter moths are confined to coastal regions and why Bruce spanworm is non-outbreak in nature, led by Hannah Broadley (UMass).

• Surveys and Data Collection

  • Ongoing surveys using pheromone traps since 2007 to map spread into central Massachusetts, to Athol (Elkinton et al. 2014, 2015).

  • Defoliation has been restricted to eastern Massachusetts.

  • A potential link between winter temperatures and outbreak density limitation in central MA is under exploration.

• Populations in Maine

  • In 2012, outbreak levels were observed for the first time in Maine, potentially linked to climate change (Elkinton et al. 2015).

History Outside North America

• Native Range

  • Extends from Europe to the Russian Far East.

  • Despite being abundant, not a severe defoliator in Europe due to the presence of natural enemies including predators and parasitoids keeping populations in check.

• Outbreaks in Europe

  • Recent outbreaks recorded in northern Norway, Sweden, Finland due to climate change facilitating movement to previously cold-restricted areas.

• Introduction to North America

  • Introduced to Nova Scotia (1930s), Oregon (1950s), British Columbia (1970s) where biological controls were implemented.

  • Two European parasitoids introduced: Cyzenis albicans (tachinid fly) and Agrypon flaveolatum (parasitic wasp).

  • C. albicans became established, helping to convert winter moths to a low-density, non-outbreak species in Canada.

  • The introduction strategy was deemed successful in Nova Scotia and Vancouver Island beginning in 1961 and late 1970s respectively.

Biological Control Implementation in New England

• Introduction Strategy

  • Initiated in May 2005 with release of 235 adult C. albicans flies in Hingham, Massachusetts, after sourcing from Canada.

  • Collectors found higher winter moth populations in British Columbia.

  • Established collection protocols to ship pupae to USDA quarantine facility for release in New England.

• Release Strategy

  • Gradually expanded release sites to multiple locations to ensure significant numbers (1600-2000 flies per site).

  • Monitoring of their establishment and the subsequent survival of winter moth populations ongoing.

Research Outcomes

• Promising Results

  • Notable declines in winter moth density and defoliation recorded in Wellesley, MA where C. albicans was established.

  • Ongoing investigation into predation impacts on reduced winter moth populations.

  • As of 2016, 41 locations have been released, with positive results of establishment at many sites, showcasing similar patterns to earlier Canadian successes.

Management Techniques

• Integrated Pest Management

  • Emphasis on preserving biological control agents like C. albicans alongside chemical management strategies.

  • Strategies include dormant oil sprays targeting eggs or biorational sprays aimed at younger caterpillar stages.

  • Future dispersal of C. albicans across impacted areas expected as the flies become established.

Conclusion

• Efforts led by Joseph Elkinton and colleagues are on track for achieving biological control of the winter moth, drawing comparisons with Canada’s historical successes.