Sprayer Performance Evaluation with Microcomputers

CROP yield and quality depend very much on the effective application of pesticides. Too little chemical causes inefficient pest control while an overdose increases cost, may damage the crop, and adds to pesticide pollution problems. Traditional approaches to teaching crop producers how to calibrate their sprayers have not been very effective. A microcomputer program, called SPRAYCAL, was developed to emphasize the economic aspects of using improperly calibrated equipment for pesticide application. This software was utilized to indicate defective nozzles and to calculate errors in travel speed and application rate at calibration clinics conducted in Iowa and Ohio during the springs of 1984, 1985, and 1986. The amount of chemicals wasted and the subsequent cost to the farmer were emphasized in the case of overapplication. Of the 32 sprayers calibrated, only seven (20%) were capable of applying a tank mix within ±5% of the intended application rate. Of those 25 sprayers showing an unacceptable performance, roughly one-third overapplied the spray mix while two-thirds underapplied.