An expert system (ES) has been developed to assist citrus spray applicators in planning and evaluating their sprayer operations. The ES is partitioned into two parts: (1) spray planning (procedures and calculations for sprayer calibration as well as suitability of spraying under given weather parameters) and (2) spray evaluation (estimation of overall spray deposition, ground fallout, and drift as percentages of the total spray discharged at orchard scale). The first part is based on established procedures and the second part is built on the previously developed spray deposition model. The latter includes a "What-If" analysis function that gives feedback on changes in input variables and the corresponding outputs. Testing of the ES revealed that the trends in the outputs, reflecting the effects of application rate, travel speed, foliage density, and percent missing trees were in general agreement with literature. The ES was evaluated by five individuals with diverse experience in spray applications. Overall, the ES was found useful for calibration and evaluation of spray applications in citrus.
