A tussock moth (Lymantria dispar
or Porthetria dispar
or Ocneria dispar
) native of the Old World, but accidentally introduced into eastern Massachusetts about 1869, where its caterpillars have done great damage to fruit, shade, and forest trees of many kinds. The male gypsy moth is yellowish brown, the female white, and larger than the male. In both sexes the wings are marked by dark lines and a dark lunule. The caterpillars, when full-grown, have a grayish mottled appearance, with blue tubercles on the anterior and red tubercles on the posterior part of the body, all giving rise to long yellow and black hairs. They usually pupate in July and the moth appears in August. The eggs are laid on tree trunks, rocks, etc., and hatch in the spring.
"By 1980 the range of habitat had advanced as far south as New Jersey, and by 1995 significant populations were found as far west as the Mississippi valley. Initial population surges along the advancing front of the inhabited area cause great damage due to defoliation of trees by the caterpillars, but over time predators, disease and other natural controlling factors tend to reduce the populations to levels not so injurious to local foliage. Much money and effort has been expended trying to control, slow, or limit the spread of gypsy moths in the United States."