Testing a Modified Airblast Sprayer for Use In Citrus

An airblast sprayer was modified with individually adjustable volume spray nozzles and an adjustable louver diverter for the lower 60% of air volume.  These are to be controlled based on laser sensor determination of tree size and canopy density.  A previously designed tower collector for spray pattern was modified to allow collection of spray driven by high velocity air at lower heights, 1 to 8 feet, for basic determination of spray deposition with height.  Surround clay product was used in the spray mix for visual determination of leaf deposition in field tests.  Without control of air flow or spray nozzle volume, excessive spray was delivered to the first 8 feet of tree height.  The effects of adjusting nozzle volume and air flow on spray deposition are reported for basic spray delivery and deposition on front and back of leaves at different tree heights and depth into the canopy. Without controls outer leaf surfaces were over-sprayed up to 8 feet of height with poor penetration to inner leaves while upper tree leaves received lower than desirable deposits.