AMHERST, Mass. A six-year campaign to control invasive winter moths with a natural parasite led by entomologist Joe Elkinton of the University of Massachusetts Amherst now has concrete evidence that a parasitic fly, Cyzenis albicans, has been established and is attacking the pest at four sites in Seekonk, Hingham, Falmouth and Wellesley. It's the beginning of the end for the decade-long defoliation of eastern Massachusetts trees by the invasive species, Elkinton says.
The researchers marked an important milestone during field work this summer and last, when they recovered winter moth larvae recently parasitized by C. albicans, the parasitic fly, at sites in the four towns. The evidence indicates that the flies had successfully overwintered and are now actively preying on the moth's young.
The winter moth, Operophtera brumata, invaded the state from Europe more than a decade ago and has caused widespread, damaging defoliation of many deciduous tree species. The moths have moved westward and recently spread to Rhode Island. In many of these areas defoliation has occurred almost every year since the infestation began. As a result, many trees have started to die. Similar winter moth invasions occurred in Nova Scotia in the 1950s and in the Pacific northwest in the 1970s. In each case, outbreaks were permanently controlled by introducing C. albicans, Elkinton adds.
"Because C. albicans was so successful in controlling winter moth in Nova Scotia and the Pacific northwest, it was natural for us to introduce it here in New England using flies my colleagues and I collected in British Columbia," he notes.
A great advantage of C. albicans is that it is highly specialized to prey on winter moths, so it does not spread to other species. Further, its numbers decline once it gains control, the entomologist points out. It is not attracted to humans or our homes and buildings, so the only impact people
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University of Massachusetts at Amherst