The effect of the matrix within which habitat fragmentation occurs was studied with respect to gypsy moth (Lymantria dispar L.) egg-mass number on the E. S. George Reserve in Livingston Co., Michigan, in October 1999. Overgrown old fields were assumed to be relatively high quality matrix compared to a large herbaceous swamp. Oak forest fragments were located in each matrix type as well as in a reference matrix of extensive oak forest. The mean number of egg masses in stands of black oaks (Quercus velutina) was determined for fragments in high and low quality matrices. A significant difference in gypsy moth egg-mass number between areas of high vs. low quality matrix was detected.