The gypsy moth, known by the scientific name Lymantria dispar, is one of North America's most devastating forest pests. The species originally evolved in Europe and Asia and has existed there for thousands of years. In either 1868 or 1869, the species (known today as one of hundreds of invasive species in North America) was accidentally introduced near Boston by E. Peopold Trouvelot. About 10 years later, the first outbreaks began in Trouvelot's neighborhood and in 1890 Massachusetts and the federal government began eradication campaigns. These attempts ultimately failed and since that time, the range of the gypsy moth has continued spreading.

Although white, chestnut, black and red oak are preferred, caterpillars also eat hundreds of other tree and shrub species including, apple, alder, aspen, basswood, birch, poplar, willow, hawthorn, hemlock and tamarack. Gardeners who don't want to pay to have their trees sprayed can often have better long-term luck by planting tree species less favored by gypsy moths. These include ash, butternut, black walnut, locust, sycamore, and yellow poplar (tuliptree).