Practical applications of plant disease modeling in IPM.

Integrated Pest Management is based on dynamic processes and requires decision-making at strategic, tactical, and operational levels. Relative to decision makers in conventional agricultural systems, decision makers in IPM systems require more knowledge and updated information, and must deal with greater complexity. It has become clear that IPM can be efficiently implemented only if the decision makers are adequately supported. Different tools have been developed for the support of decision-making in plant disease control, and these tools can be grouped in three categories: warning services, on-site devices, and decision support systems (DSSs). These tools work at different spatial and time scales, are provided to users by both public and private sources, focus on different communication modes, and can support multiple options for delivering information to farmers. Plant disease models are key components of any decision-support tool for disease control. Plant disease models produce predictions about the epidemic or single epidemic components that can be used as risk indicators. Characteristics, weaknesses, and strengths of the currently available decision tools are discussed and a new generation of model-based DSSs is shown, which is characterised by: i) a holistic treatment of crop management problems (pests, diseases, pesticide application timing and rates, etc.); ii) a conversion of complex decision processes into simple and easy-to-understand decision supports; iii) easy and rapid access through the Internet; and two-way communication between users and the provider that make it possible to consider contextspecific information