A computer program to improve the control of grapevine downy mildew

A description of a software program for the simulation of grapevine downy mildew (Plasmopara viticola) biology and its mathematical model are shown in this paper. It represents an improvement of the software PLASMO presented in a previous report by the authors. The model describes the development of the pathogen through computations based on weather data and it allows farmers to reduce the number of chemical treatments needed to control the fungus attacks. The improvements, suggested by several field experiments under different conditions, are discussed. The program has been shown to be a useful instrument for deducing the best moments for the fungicide application, on the basis of graphics and numeric values, during vineyards trials performed in Tuscany (central Italy) in the years 1992 and 1993. The user's interface, providing a friendly approach to the simulation and management of disease control, is fully described.