For most fungicides, the applications must be made before the disease begins because the materials control by prevention and not by eradication of the pathogen after the organisms are inside the plant. Lower volumes and lower pressure can be used, but are not usually as effective. Kentucky's vegetable growers, as a whole, need to pay more attention to this area. Sprayer nozzles should be those made for fungicide use, clean, and without excessive wear. Spray adjuvants or surfactant should be used if the product label recommends it.
Surfactants are most valuable in cole crops and peppers due to the waxy leaf.
When possible, applications should be made when the air is still. Sometimes crop damage results from fungicide use. It is important to maintain application intervals. If it rains before the material is dry on the foliage, most of the material will wash off. Regular applications are needed to keep up with new growth of the plant and loss of the applied material due to weathering.