Gypsy moths, Lymantria dispar, are defoliators and they prefer to feed on poplar, oak, willow, and basswood species. They will also feed on other species, but they do tend to avoid ash, balsam fir, butternut, black walnut, red cedar, flowering dogwood, sycamore, yellow or tulip poplar and shrubs such as mountain laurel.
Sometime between 1868 and 1869 European gypsy moths were accidentally released in Massachusetts by French scientist, E. Leopold Trouvelot, after a failed attempt of trying to utilize them for silk production. Gypsy moth eggs masses can be transported to South Dakota on any items that are stored outdoors and can be moved. For example, people relocating to South Dakota and moving all of their lawn furniture.
Gypsy moth larva, Jon Yuschock, Bugwood.org
Male Gypsy Moth, Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org
European Gypsy Moth, Female (top) and male (bottom), USDA, APHIS, Plant Protection and Quarantine Archives
Small populations can be kept in check by predator birds, insects, and possibly small mammals until a major outbreak occurs. In the past and present years, gypsy moth adults have been collected from gypsy moth traps in South Dakota. However, the population isn’t large enough to sustain itself at a level where it will become an issue. Gypsy moth larvae can be found in groupings of around 5, or 6, but also in masses with 50 or more larvae on a tree. Larvae will continuously eat in large groups. Gypsy moth larva are easy to identify by looking for the 12 red dots and 10 blue dots on their abdomen.