US: Changes recommended in tomato spray program
This group, called the Qoi’s, includes Quadris, Cabrio, and Tanos – mainstays of many tomato spray programs. Many populations of the early blight fungus in Tennessee and other states are totally resistant to this group of fungicides. If your tomato crops have shown unusual blight severity the last few years despite regular (weekly) fungicide sprays, resistance is probably the reason. That is assuming, of course, that a Qoi was used frequently, about every other fungicide application.
What changes should you make in your spray program? Since early blight is the driving force for the tomato spray program, a product having at least moderate activity against early blight should be used in each spray.
Research in Tennessee has shown that Fontelis and Inspire Super provide outstanding control of early blight. Both products can be used in a program because they are in different mode of action groups. Because of limitations on the number of times that these products can be used, both will need to be included.
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