A computerized forecasting system for A. solani on tomato (FAST) was developed to identify periods when environmental conditions are favorable for tomato [Lycopercicon esculentum] early blight development and to provide a schedule for efficient fungicide applications. The forcasting system incorporates 2 empirical models based on the following daily environmental parameters: maximum and minimum ambient air temperature, hours of leaf-wetness, maximum and minimum temperature during the wetness period, hours of relative humidity greater than 90% and rainfall. Disease severity data from epidemics subjected to FAST-generated spray schedules were compared with a nonsprayed check and with weekly spray schedules that were started 2- and 4 wk after transplanting. There were no significant differences among final disease severity and apparent infection rates. The disease levels corresponding to these spray schedules were significantly less than the nonsprayed check. The FAST-generated schedules required fewer fungicide applications to achieve the same level of control as the weekly schedules.