Droplet Size Effect on Spray Deposition Efficiency of Citrus Leaves

ABSTRACT THE objective of this laboratory study was to identify a droplet size range for maximum spray deposition efficiency on citrus leaves. Using a vibrating orifice droplet generator, a wind tunnel and two spray fluids, different sizes of uniform droplets were generated and sprayed towards pairs of targets. The targets, comprising a filter paper and one of four types of leaf surfaces, were held at three distances from the wind tunnel exhaust and were moved at three speeds across the stream of droplets. For each target condition, spraying was replicated 6 times. Assuming that filter paper targets retained 100% of the impacted droplets, percentage of droplets (by weight) retained by leaf targets was used as deposition efficiency criterion. Considering all target conditions, droplet size range of 240 to 340 /itm gave the highest deposition efficiency.