Background
Medford, Massachusetts
The gypsy moth is native to Europe and Asia and is a major introduced pest of eastern United States hardwood forests. The gypsy moth is found mainly in the temperate regions of the world, including central and southern Europe, northern Africa, central and southern Asia, and Japan. The gypsy moth was originally introduced into Medford, Massachusetts in 1869 by Leopold Trouvelot, a French astronomer with an interest in insects. Trouvelot wanted to develop a strain of silk moth that was resistant to disease as a part of an effort to begin a commercial silk industry. However, several gypsy moth caterpillars escaped from Trouvelot's home and established themselves in the surrounding areas. Surprisingly, it wasn't until 20 years later that the first outbreak occurred. Despite all control efforts since its introduction, the gypsy moth has persisted and extended its range. In the United States, the gypsy moth has rapidly moved north to Canada, west to Wisconsin, and south to North Carolina. Gypsy moth caterpillars defoliate millions of acres of trees annually in the United States.
In Virginia
defoliation,
Shenandoah National Park
The first gypsy moth was found in Virginia in Shenandoah National Park (Albemarle County) in 1969, probably transported on a visitor's vehicle. That area was treated with insecticide and the population was apparently eradicated. Natural spread of the population reached northern Virginia in 1980. Virginia experienced its first gypsy moth defoliation in 1984. Now, most of Virginia falls into the federally regulated (quarantined) area.
Impacts
Gypsy moth has defoliated nearly 90 million acres nationwide since records were first recorded in 1924. In Virginia, historical defoliation is nearly 5.5 million acres with a suppression cost of over $17 million. These costs do not include the economics associated with tree mortality, reduced tourism and adverse recreational and residential impacts due to defoliation and the nuisance of large numbers of caterpillars in and around dwellings and public areas.