Late blight has the potential to be one of the most destructive diseases for potato growers. Late blight is influenced largely by environmental conditions, and management under semiarid conditions can be quite different from management under wet, humid conditions. This presentation outlines effective control practices for growers who raise potatoes under semiarid conditions. It addresses the effect of irrigation on late blight, fungicide efficacy against late blight, the impact of weather, timing of fungicide applications, the effect of application method on fungicide residue, and the role of postharvest products.