MAA NEWS MAA NEWS March 18_w - Page 14

Winter Moth Numbers at a Record Low Promising Data from the Elkinton Lab by Tawny Simisky It’s that time of year again, following the emergence of winter moth (Operophtera brumata) adult moths, where anyone with vested interest in the health of oak, maple, apple, and many other deciduous plants such as cherry, basswood, ash, white elm, crabapple, and blueberry, begin to wonder what is currently known about the winter moth population in Massachusetts. Dr. Joseph Elkinton, Professor of Environmental Conservation at the University of Massachusetts, Amherst, MA, has excellent news for us all: data from his lab’s research locations in eastern Massachusetts suggest that this invasive pest’s population size is at an all-time low. In fact, the 2017 winter moth population was the lowest they have seen since studying and working toward the biological control of this insect for the past 13 years. Hopefully, this will mean low winter moth caterpillar numbers for the 2018 season, in most areas where they are present in eastern Massa- chusetts. Winter moth outbreaks and subsequent defoliation of the above- mentioned host plants were first noticed in Massachusetts on Cape Ann on the North Shore and near Cohasset, Hingham, and Rockland on the South Shore in the late 1990’s. At the time, this defoliation was thought to be caused by a native insect. How- ever, the persistence and severity of the outbreak in Plymouth County caused Deborah Swanson, UMass Extension Horticultur- ist for Plymouth County, Retired, to send caterpillars to UMass Extension Entomologist Robert Childs and Dr. Elkinton to further investigate what species could be responsible. In 2003, following a collaborative effort with UMass Extension and Plymouth County Extension, Dr. David Wagner of the Uni- versity of Connecticut and Richard Hoebeke of Cornell Univer- sity confirmed that winter moth (Operophtera brumata) was responsible. Over the next decade, winter moth caused defolia- tion spread over all of the North Shore into the western suburbs of Boston and across the South Shore onto Cape Cod and Martha’s Vineyard and into Rhode Island and coastal Maine. W