VALIDATING MATHEMATICAL-MODELS OF PLANT-DISEASE PROGRESS IN-SPACE ANDTIME

Experimental studies of the dispersal of plant pathogens, and of the r esulting patterns of disease, have long been an important component of botanical epidemiology. Many statistical methods have been developed for the description of the observed patterns of disease. More recently , the spatial aspects of plant disease have been incorporated into mat hematical models of epidemics. Model validation usually takes the form of a comparison between the model output and real data; but often the comparison is only an informal one. The use of experimental data to d evelop empirical generalizations of the characteristics of patterns of plant disease provides an opportunity for a more stringent validation of models of the spatial dynamics of plant-disease epidemics.