Parasitic Flies That Control Invasive Winter Moths to Be Released May 9 in Wellesley by UMass Amherst Researchers

May 8, 2008

Contact:

Joseph Elkinton 413/545-4816 (office); 413/531-9512 (cell)

AMHERST, Mass. – A team of scientists led by Joseph Elkinton at the University of Massachusetts Amherst will release approximately 1,000 parasitic flies at Centennial Park in Wellesley on Friday, May 9 at 10 a.m. to control the winter moth, a new invasive species in eastern Massachusetts that is now in the process of stripping the foliage from many kinds of deciduous trees in towns that stretch from the North Shore to Cape Cod.

Members of the press, including videographers and photographers, who wish to attend should meet on the circle at the end of Maugus Ave. in Wellesley, close to the intersection of Routes 9 and 16.

The fly, known as Cyzenis albicans, is an important natural enemy of the winter moth that has successfully controlled the moth in earlier invasions of Nova Scotia and the Pacific Northwest. Elkinton and his colleagues are confident that this fly will eventually suppress winter moth populations in Massachusetts to harmless levels. That is what happened in Nova Scotia, where the fly was introduced in the 1950s, and where winter moths have been at low levels ever since. It will take a few years, however, for a few thousand flies to catch up with a population of winter moths that numbers in the trillions. In Nova Scotia it took six years.

The research team is also confident that the fly will not cause other problems. Research has shown that it attacks only the winter moth, and will not attack other species of caterpillars.

The Cyzenis release project is a cooperative effort between the University of Massachusetts, the USDA Forest Service, the USDA Animal and Plant Health Inspection Service, the Massachusetts Department of Conservation and Recreation and the Plymouth County Cooperative Extension.

Both the winter moth and the parasitic fly originated in Europe. The fly makes a living by laying its own eggs on foliage being eaten by winter moth caterpillars. The caterpillars consume the eggs, which hatch inside the caterpillar and develop into a larval fly. The winter moth caterpillars drop to the ground in late May to form pupae in the soil. Winter moth pupae containing the larval fly eventually die and an adult fly emerges from the pupae the following spring to attack more winter moth caterpillars.

The flies to be released May 9 originated from a population collected in Victoria, British Columbia. They were shipped to the USDA APHIS quarantine facility at Otis Air Base on Cape Cod and grown from winter moth larvae that were infected one year ago in Elkinton’s lab. George Boettner, a technician in Elkinton’s lab, has perfected a technique for infecting large numbers of winter moth caterpillars with the fly. Many of the caterpillars were reared on an artificial diet developed in collaboration with colleagues at the USDA APHIS lab. Elkinton and his colleagues hope to continue the process of rearing and releasing flies until they start to recover them in large numbers in Massachusetts, at which point winter moths should cease to be a problem.

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