UMass-Amherst scientists claim victory over the moth, the coastal threat now a "no-harm"

AMHERST – The insect that caused the defoliation of trees and blueberries across the New England coast has apparently reached its peak: a parasitic fly introduced into areas affected by researchers at the University of Massachusetts at Amherst.

"After 14 years of effort, we have successfully converted a snow borer, a major new defoliator invading eastern New England, into a permanent insecticide," said UMass entomologist Joseph Elkinton. in a statement. "I am pleased to announce that we have now saved millions of dollars of pesticides, now and in the future, from Massachusetts residents, who are fighting defoliation of their trees. backyard and their blueberry crops.

"We avoided what would become another major disaster for the United States, comparable to the gypsy moth," said Elkinton.

The research team led by Elkinton, George Boettner and Hannah Broadley introduced the parasitic fly called Cyzenis albicans in areas where the winter moth had established its pattern of leaf consumption. Flies only attack winter moths in an approach called biological control.

"The purpose of biological control is to reduce the density of invasive species to non-harmful status," said Elkinton. "That's what we think we've achieved." One of the key features of Cyzenis albicans, the parasitoid that we have published, is that it seems to be an absolute specialist. It feeds only on snow moth. Other worms in native inches are not attacked. "

Elkinton and Boettner launched the biocontrol program in 2005 by collecting specimens of Cyzenis albicans, which had reduced the populations of Europeans in Nova Scotia and British Columbia. UMass researchers raised flies and released them in the spring in about two dozen sites in New England affected by moths. In July 2018, they had established Cyzenis albicans populations in 38 sites.

Winter moths arrived in Nova Scotia from Europe before 1950, then another European invasion of the disease hit New England in the 1990s, the researchers said. Defoliation was first observed north and south of Boston in 2003 and has spread over most of eastern Massachusetts, Rhode Island, southeastern Connecticut and Canada. of the Maine coast during the next decade.

The caterpillars have damaged trees, orchards and blueberries.

The insect is so named because adults emerge in November and reproduce. The eggs hatch in April and the larvae dig the buds of the leaves of the trees. As caterpillars, they feed on leaves until they fall to the ground at the end of May, burying themselves in the soil and pupating until the beginning of the year. process in winter.

Elkinton said that the winter months seem unable to survive in the interior of New England, including in western Massachusetts, because winters are generally colder than along the coast. the coast. But the UMass entomology team is hosting samples from residents of western New England who think they have the pest in their trees to test them out. They said new versions of the Cyzenis albicans flies can be requested.