CELS Scientists Release Parasitic Flies to Fight Invasive Moths

Media Contact: Todd McLeish, 401-874-7892

Heather-FaubertA scientist from the University of Rhode Island’s Biocontrol Lab released thousands of parasitic flies last month in an effort to combat an invasive moth that is defoliating trees throughout the state.

Heather Faubert, coordinator of URI’s Plant Protection Clinic, says that the caterpillars of winter moths, which are native to Europe and arrived in Rhode Island in the last decade, have been found this year in large numbers in many of the state’s coastal communities, as well as in inland areas like Lincoln and Cumberland.

Because the moths have no known predators in the region, Faubert has worked with colleagues at the University of Massachusetts to rear and release a parasitic fly, Cyzenis albicans, that has successfully reduced the moth population in Nova Scotia, where the moths were first found in the 1950s. The fly lays its eggs on tree leaves, and when the moth caterpillar eats the leaves, it ingests the eggs, whereupon the fly larva grows inside the caterpillar and consumes it from the inside.

“I’ve been working on this project since 2005 when our winter moth populations were quite low,” said Faubert. “You need large populations of the moths for the flies to do their job, so I spent several years scouting around the state looking for large moth populations.”

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