Populations of the gypsy moth (Lymantria dispar(L.)) have been monitored in Michigan since 1985 using a permanent statewide grid of more than 2,000 pheromone traps. Trap catch data were analyzed using a computerized Geographic Information System (GIS). Using trap catch data from 1985 to 1987, a regression model (R2= 0.79) was developed to predict adult male moth catch for 1987 using three risk levels of gypsy moth population densities (low, medium, and high). Trap catch data and data on defoliation were combined in the GIS, demonstrating that adult male moth catch can be a good indicator of potential defoliation in the following year. The regression model was then used to predict low, medium, and high risk areas for moth populations for the next year.