ISHS Acta Horticulturae 724: IX International Symposium on the Processing Tomato
MODERNIZING THE DELIVERY OF TOM-CAST |
| Authors: | R.E. Pitblado, I. Nichols, J. Winter |
| Keywords: | processing tomatoes, plant diseases, weather-timed fungicide sprays |
| Abstract:
Fungicides are regularly applied to processing tomato fields at frequencies which at times can be excessive. In an effort to aid growers in a more strategic application approach, disease-warning models were developed to increase the accuracy and reduce the number of seasonal fungicide applications. Disease-warning models are mathematical descriptions of the interaction between environmental variables that can result in plant disease. The output of a model produces an index of predicted disease risk. TOM-CAST is an example of a disease-warning model which establishes a timed fungicide spraying program for processing tomatoes. This particular model is based upon weather data, specifically hourly leaf wetness and temperature. The output of the TOM-CAST model produces daily disease severity values (DSV). Disease control is obtained from the accumulation of daily DSV’s which reach a threshold number and indicate a recommendation for a foliage fungicide application. It has been recently noted that the spatial accuracy of the seasonal spraying applications could potentially be further enhanced if the TOM-CAST model became site specific. Site specific integration within the TOM-CAST model is now feasible with the advancement of geographical information systems (GIS) and an improved agricultural microclimate network called the Ontario Weather Network. From the initial beginnings of the development of TOM-CAST in the early 1970s to the more sophisticated delivery in the year 2004 the tomato industry has gained considerably in the modernization of this decision based model. | |
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