Mass Balance of Citrus Spray Applications

A sampling system was used to quantify on-canopy spray deposition and off-target losses from five air-carrier sprayers commonly used in citrus applications. The samplers consisted of continuous lines (loops) of cotton ribbon that stretched out above tree canopies, on tree sides, and above orchard floor. They extended to the third rows on each side of the application line. The sprayers had different design configurations and their airflow rates, nozzle selections, droplet size spectra, and operating parameters varied markedly. Spray solutions containing a fluorescent tracer were applied between two tree rows, the targets were collected in small segments, and spray deposition on various sample sections was quantified by fluorometry. The study was conducted in five replications.