ABSTRACT
Three tomato disease forecasting systems - FAST, CUFAST, TOM-CAST - have been developed and used in certain locals for scheduling fungicide applications to control Alternaria solani on tomatoes allowing fungicides to be applied "as needed" and affording the possibility of reducing fungicide applications while maintaining crop quality. Cowgill, Maletta and Johnston have evaluated these forecast systems since 1989 and have demonstrated the potential to control early blight with reduced numbers of applications under northern New Jersey climatic conditions. Resulting estimated annual cost savings per acre (labor, equipment, Bravo 720 at 3 pts/acre), averaged over the years that each forecast system has been evaluated, are: FAST - $230; CUFAST - $252; TOM-CAST - $483.

Extrapolating to 800 acres of fresh market tomatoes produced in North Jersey, the potential cost savings for four years based on the average number of sprays eliminated with TOM-CAST would have approached $1.5 million. Reduction in pesticide inputs would have approached 83,000 lbs a.i. for a four year period. With the more conservative CUFAST, cost saving would have exceeded $ 0.8 million. Tomato disease forecasting has potential to offer important benefits to New Jersey's fresh market tomato industry.

The TOM-CAST system appears to have some important advantages over the other forecast systems. In order to implement this system in a program for tomato growers, specific thresholds must be identified in field trials taking place over several seasons in order to account for year to year weather variability. The possible disadvantages of TOM-CAST, suggested by our 1993 and 1994 research results but not apparent in 1995, must be investigated.

In order for a forecasting system to be fully implemented, the benefits of this approach to disease control must be clearly documented through research and demonstrated in grower trials. The effectiveness of the forecast system and the economic parameters related to its use will be the primary considerations for individuals, organizations and programs looking to implement disease forecasting, so they must be thoroughly documented. Since reliable weather information at reasonable cost will also be essential to implementation, rigorous evaluation of equipment and services that may fill this need is required