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, Indiana, Maine, North Carolina, Wisconsin, and Wyoming. The U. S. Department of Agriculture reports that virtually all areas that have experienced an invasion of gypsy moths continue to have extremely high levels of infestation.
Gypsy moths have a voracious appetite for leaves, and the primary environmental problem caused by them is the destruction of huge areas of forest. Gypsy moth caterpillars defoliate a number of species of broadleaf trees including birches, larch, and aspen, but prefer the leaves of several species of oaks, though they have also been found to eat some evergreen needles. One caterpillar can consume up to one square foot of leaves per day. In 2001, 84.9 million acres (34.4 million ha) had been defoliated by these insects. The sheer number of gypsy moth caterpillars produced in one generation can create other problems as well. Some areas become so heavily infested that the insects have covered houses and yards, causing psychological difficulties as well as physical.
There are few natural predators of the gypsy moth in North America, and none that can keep its population under control. Attempts have been made since the 1940s to control the insect with pesticides, including DDT, but these efforts have usually resulted in further contaminating of the environment without controlling the moths or their caterpillars. Numerous attempts have also been made to introduce species from outside the region to combat it, and almost 100 different natural enemies of the gypsy moth have been introduced into the northeast United States. Most of these have met, at best, with limited success. Recent progress has been made in experiments with a Japanese fungus that attacks and kills the gypsy moth. The fungus enters the body of the caterpillar through its pores and begins to destroy the insect from the inside out. It is apparently non-lethal to all other species in the infested areas, and its use has met with limited success in parts of Rhode Island and upstate New York. It remains unknown however, whether it will control the gypsy moth, or at least stem the dramatic population increases and severe infestations.
[Eugene C. Beckham ]
Pond, D., and W. Boyd. "Gypsy on the Move." American Forests 98 (March–April 1992): 21–25.
Gypsy Moth in Virginia. April 10, 2001 [cited May 2002]. <http://www.gypsymoth.ento.vt.edu/vagm/index.html>.
U.S. Department of Agriculture. "Plant Protection and Quarantine: Gypsy Moth Quarantine." Animal and Plant Health Inspection Service. June 15, 2001 [cited May 2002]. <http://www.aphis.usda.gov/ppq/maps/gypmoth.pdf>.
gyp·sy moth • n. a tussock moth (Lymantria dispar) having a brown male and larger white female. The caterpillar can be a serious pest of orchards and woodland.