The gypsy moth (Lymantria dispar) was brought to the U.S. in 1869 to experiment with silk production. Populations soon established and the pest has been expanding in distribution since. Adult females are not able to fly. Gypsy moth larvae spin a thread of silk and disperse in the wind. It is estimated that this natural spread would be about 2 miles per year. The actual rate of spread has been much greater due to human aid, primarily by movement of nursery stock and automobiles.
|Egg Masses:Pennsylvania Department of
Conservation and Natural Resources
- Forestry Archive
|Larva: Bill McNee, Wisconsin
Dept of Natural Resources
|Adult male and female: John H. Ghent,
USDA Forest Service
No gypsy moths were captured in traps in North Dakota in 2005-2013. In the past several years, infestations have been found in the Twin Cities area of Minnesota, more recently large numbers of moths have been caught in the arrowhead region. Steps are being taken to slow gypsy moth spread. Trees, Christmas trees, shrubs and logs from quarantined areas must be certified before movement. State and federal agencies use pheromone traps to detect outlying populations. Eradication measures are taken if outlying sites are determined to have established gypsy moth populations. Since 1993, officials have implemented a “Slow the Spread” program that uses intensive sampling and precise population control techniques. The program is concentrated on a 100 mile wide band bordering the generally infested area. The rate of spread has been about half as fast since implementation of the program. This program has been implemented in the arrowhead region of Minnesota since 2003.
Gypsy moths feed on a wide range of trees and shrubs and could be transported on any nursery stock or Christmas trees brought into the state from quarantined areas. Closely inspect and monitor stock received from these areas and ensure shipments are accompanied by a federal certificate or stamp demonstrating compliance.