New UMaine Browntail moth report sheds light on how the scourge began, and where we are heading

Wed, 06/16/2021 - 10:30am

    Did you know that when the Browntail moth first spread across the North East, at the turn of the 20th Century, there was a tremendous effort to contain them, including the use of, “insecticide spraying, biological control, public action initiatives, and changes in the landscape,” according to a new report from UMaine. But, cold winters, as was the norm then and not now, still did not kill the larvae. The struggle to contain the moths for the sake of human health and certain tree species was just as arduous as it is today.

    The latest academic study, “Browntail Moth Research at the University of Maine: A Report of Activities and Findings 2016–2020,” was released June 15. It provides a broad and thorough overview of how the scourge began, and details current efforts to destroy the moths, while peering into the future.

    The group of University of Maine researchers, led by faculty in the School of Biology and Ecology, investigated the spread of the pest from coastal communities to nearly all of Maine’s 16 counties. 

    Professor emerita Eleanor Groden co-authored the report in collaboration with colleagues and students in UMaine’s chemistry department and with the Maine Agricultural and Forest Experiment Station. Staff from the Maine Department of Agriculture, Conservation and Forestry also contributed to the research, which received support from a number of public, private and nonprofit partners. 

    Co-author Angela Mech, a UMaine assistant professor of forest entomology, has assumed leadership of the browntail moth project following Groden’s retirement. Mech’s other research interests include insect biodiversity, forest health and invasion ecology. 

    The browntail moth report will be updated and shared with the public as research continues and new information about the moth emerges.
    “Browntail moth is an invasive forest pest that was accidentally introduced in 1897 from Europe into Cambridge, Massachusetts,” the report said.
    “After its initial establishment, the insect rapidly spread through the northeast, encompassing an area of 150,000 km2 from Long Island, New York, to New Brunswick, Canada. During this period, the U. S. Department of Agriculture launched a massive biological control effort to introduce natural enemies from the native range of this insect into these areas. After this rapid expansion, browntail moth populations declined in the 1920s and 1930s, likely due to a combination of insecticide spraying, biological control, public action initiatives and changes in the landscape. There were some small outbreaks in the historic range in the 1960s.
    “ Since the time of its range retraction, browntail moth populations have remained in small isolated areas of the Casco Bay Region, Maine and on Cape Cod, Massachusetts. Since the early 1990s, small, localized outbreaks of browntail moth (100 to 10,000 acres) have occurred infrequently in communities along the coast from Freeport to Georgetown and surrounding Merrymeeting Bay. However, from 2016 to 2019, Maine has experienced a dramatic increase in the infestation area such that as of winter 2020, traces of populations were found as far north as Calais, Maine, as far inland as Cambridge, Maine, and as far south as Scarborough, Maine.”