UMass Extension Landscape Message June 8, 2012
"Winter Moth caterpillars have pupated and the feeding damage for this year is over. Complete defoliation of trees occurred in certain areas of MA and Rhode Island this spring. A new outbreak of winter moth was discovered in Harpswell, Maine (Cumberland County: approximately 400 acres), which is a first find for that state. Male moths have been collected in that county in southeastern Maine for many years but numbers were always so low that outbreaks had not yet occurred. Winter moth movement has been traced with pheromone traps and DNA analysis from the established population in Nova Scotia down the coasts of Maine, New Hampshire, Massachusetts and Rhode Island (and now CT). It is also possible to inadvertently move the insect via soil when moving plants from areas of infestation, such as eastern MA to other geographic locations (generally from June into December). Citizens are especially encouraged to take great care when thinking about moving plants from areas with winter moth infestations to new areas where the pest does not yet exist."
The note about moving winter moths in soil of plants is sobering.