Spray Drift From Ground and Aerial Applications

Abstract

A field test was conducted to quantify spray drift from typical spray applications of citrus in Florida. Spray equipment included both fixed-wing and rotary-wing aircraft and high- and low-volume airblast ground sprayers. Spray solutions containing a fluorescent tracer dye were applied to the four tree rows, closest to the downwind edge of an orange grove, under commonly practiced operational conditions. Mylar targets as well as air samplers were used to sample spray fallout and airborne drift at several locations downwind of spray applications. All applications resulted in measurable drift up to 195 m downwind and more than 70% of drift deposits (including swath displacement) originated from sprays applied to the last two rows of the trees closest to the drift line. Averaged over all distances and replications, the highest and lowest drift fallout were from the fixed-wing and low-volume ground sprayer (2.4:1), but, the highest and lowest airborne drift were from low-volume and high-volume ground sprayers (2.6:1), respectively.