One of the main goals of the study of plant pathology is the development of methods for reducing crop losses caused by plant diseases. In many crops, growers rely on calendar-based spray programs for disease management. This strategy generally provides adequate disease suppression. However, as it totally ignores the factors governing pathogen development and the occurrence of epidemics, it often results in the application of unnecessary surplus pesticides. Furthermore, occasionally, despite the intensive application of fungicides, diseases develop and yields are impaired. Obviously, this type of spray program is not the optimal strategy for disease management. The contribution of epidemiological research to plant disease management is illustrated in this paper using examples taken from over 15 years of research in Israel. Four case studies are presented, in order of increasing complexity of the pathosystem: ascochyta blight in chickpea, grey mould in sweet basil, powdery mildew in grape and grey mould in greenhouse vegetables. Epidemiological studies of each of these pathosystems have provided new insights into the factors governing disease outbreaks, which have led to the development of improved management strategies. These strategies are currently used by Israeli growers, enabling them to adequately suppress these pathogens with fewer fungicide applications.