Technical Abstract: Historical and current information is presented on the use of mating disruption to manage sparse-density populations of the gypsy moth. The biology of mating disruption of the gypsy moth, and pre- 1989 studies relating to initial developments of application technology, is reviewed, and year-by-year results of studies conducted by the Gypsy Moth Mating Disruption Working Group is presented. In 1989-97, 31 generally successful (based on subsequent-year pheromone trapping) operational projects were conducted 5 states (= 51,719 acres). From 1991-1997, plastic flake and bead pheromone release systems were evaluated in aerial application studies in replicated plots and characterized for particle-size distribution, release rate, residual activity, ease of application, deposition, and efficacy under field conditions. A dose-response study (1992), a reduced-disparlure dose study (1993), an increased-disparlure dose study (1994), a second-year-effects study (1995), a tank-mix study comparing candidate adjuvants (1996), and a flake distribution study (1997), have all contributed to current (1998) formulation, dose, and usage-pattern protocol recommendations by the USDA.