Spray Drift, Operator Exposure, Crop Residue and Efficacy: Early Indications for Equivalency of Uncrewed Aerial Spray Systems with Conventional Application Techniques

Abstract

Highlights Initial data shows UASS spray drift is greater than ground, less than aerial, and similar to an airblast application. Operator exposure with UASS is less than that of a backpack sprayer. No current data shows that residues on crops from UASS applications would be different than conventional applications. UASS applications generally have similar efficacy as their conventional counterparts. Abstract. Uncrewed Aerial Spray Systems (UASS) are being adopted at a rapid pace in agricultural applications of crop protection products. The data required to effectively regulate their use must be gathered to position UASS in terms of equivalency with other conventional practices. In Fall 2021, the CropLife America Drones Working Group initiated an effort to collect published information on establishing the equivalency of UASS applications with conventional application types as it relates to spray drift, operator exposure, crop residue, and efficacy. Based on the published literature, our comparison demonstrated that UASS spray drift is lower than aerial, higher than ground boom, and similar to orchard airblast applications. However, this comparison is based on limited data and needs further confirmation. Individual use cases and other application variables will need to be considered to determine if this generalization applies (e.g., adjuvant use, rotor and nozzle configuration, etc.). For operator exposure, this work supported the current consensus that applications with UASS have less potential for exposure in some respects (e.g., compared to backpack applications), but for other job steps that are unique to UASS (such as mixing and loading) more information is needed. With respect to crop residue, UASS applicators follow the label for conventional application techniques with the same directions for use (i.e., application rate, pre-harvest interval, and number of applications), but there is no evidence that pesticide residues resulting from a UASS application are any different to conventional application techniques. In terms of efficacy, applications with UASS tend to be equivalent to conventional methods; however, more information is needed, especially where good coverage is a requirement. The assessment of published literature on UASS demonstrates potential equivalency in certain key areas and supports the responsible use of this emerging technology, while more information on spray distribution within the target zone, off-target droplet movement, operator and bystander exposure, and pesticidal efficacy continues to be generated. Keywords: Drone, Efficacy, Emerging technology, Operator exposure, Pesticide, Residue, Spray drift, UASS.