The gypsy moth (Portheria dispar), a native of Europe and parts of Asia, has been causing both ecological and economic damage in the eastern United States and Canada since its introduction in New England in the 1860s.

In 1869, french entomologist Leopold Trouvelet brought live specimens of the insect to Medford, Massachusetts for experimentation with silk production. Several individual specimens escaped and became an established population over the next 20 years. The destructive abilities of the gypsy moth became readily apparent to area residents, who watched large sections of forest be destroyed by the larvae. From the initial infestation in Massachusetts, the gypsy moth spread throughout the northeastern United States and southeastern Canada. As of 2001, the following states were quarantined: Connecticut, Delaware, Maryland, Michigan, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont. More that two-thirds of Virginia is quarantined, as well as sections of Ohio...