Recent advances in personal computer hardware and the rapid development of spatial analysis software that is user-friendly on PC's has provided remarkable new tools for the analysis of plant diseases, particularly ecologically complex virus diseases. Due to the complexity of the disease cycle of the animal-vectored plant virus, these diseases present the most interesting challenges for the application of spatial analysis technology. While traditional quantitative analysis of plant diseases concentrated on within-field spatial analysis, often involving rather arcane mathematical descriptions of pattern, the new spatial analysis tools are most useful at the dimension where many disease epidemics occur, the regional level. The output of many of the programs used in spatial analysis is a highly visual picture of a disease epidemic which has a strong intuitive appeal to managers of agricultural enterprises. Applications by us, thus far, have included tomato, pepper and cotton virus diseases in Arizona, Mexico, California and Pakistan. In addition, this technology has been applied by us to Phytophthora infestans in potato and tomato. Aspergillus flavus in cotton, and regional insect problems of tomato and cotton.