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Disease Control and Pest Management

FAST, a Forecast System for Alternaria solani on Tomato. L. Madden, Graduate Assistant, Department of Plant Pathology, The Pennsylvania State University, University Park, PA 16802; S. P. Pennypacker(2), and A. A. MacNab(3). (2)(3)Assistant Professor, and Associate Professor, respectively, Department of Plant Pathology, The Pennsylvania State University, University Park, PA 16802. Phytopathology 68:1354-1358. Accepted for publication 6 March 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1354.

A computerized forecasting system for Alternaria solani on tomato (FAST) has been developed to identify periods when environmental conditions are favorable for tomato early blight development and to provide a schedule for efficient fungicide applications. The forecasting system incorporates two 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 the FAST schedules and the weekly schedules with regard to 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.