Selection of the least drifting spray nozzles for pesticide application to protect insect pollinators

Authors: Kannan, Narayanan; Read, Quentin

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2025
Publication Date: 2/10/2026
Citation: Kannan, N., Read, Q.D. 2026. Selection of the least drifting spray nozzles for pesticide application to protect insect pollinators. Journal of the ASABE, 69(1), 77-91.https://doi.org/10.13031/ja.16415.
DOI: https://doi.org/10.13031/ja.16415

Interpretive Summary: Previous studies have found that pesticide drift can harm honeybees and other pollinators. This is a growing concern for beekeepers in Mississippi and this risk can be reduced by using spray nozzles that minimize drifting. This study aimed to find the best nozzles for reducing pesticide drift with the following objectives a) Examine the size, speed, and flow of liquid spray from 17 different nozzles. b) Measure how much of the spray is made up of tiny droplets that can drift, c) Study the relationship between droplet size and speed for each nozzle. d) Identify nozzles that are least likely to cause drift. The flow rate for each nozzle was measured via a SpotOn spray calibrator. A custom-built spray system was used to conduct the experiment. Droplet size and speed were observed with an image analyzer. The observations were analyzed to quantify three important metrics of droplet size and speed—small (10th percentile), medium (50th percentile), and large (90th percentile). The study also calculated the percentage of spray made up of very fine droplets (smaller than 150 micrometers). Additionally, statistical analysis was used to examine how the nozzle type, pressure, and height affect spray performance. The results show that the size of the spray nozzle’s entry opening controls how much liquid comes out of the nozzle. The ratio between the entry and exit openings affects how much spray can drift away. Based on the Of the nozzles tested in the study, some such as air induction nozzles and the AITTJ60—110025 were best at reducing the amounts of liquid spray that can drift. Others, such as DG8002, DG8003, DG8004, TT11001, and AIXR11002 created a moderate amount of liquid that can drift away. These findings can help producers choose the right nozzle to reduce amounts of liquid spray that drifts away from the intended target, improving application efficiency, and protecting pollinators.

Technical Abstract: Pesticide exposure, including off-target drift, is troubling the thriving beekeeping industry in Mississippi. The selection of the least drifting spray nozzle(s) is one way to protect insect pollinators. The major goal of this study is to identify nozzles with low drift for pesticide spray applications. The specific objectives include (a) observing the size, speed,and flow rate data from seventeen broadcast nozzles; (b) estimating the proportion of spray volume with driftable size droplets; (c) estimating the size and speed relationships for all the nozzles; and (d) identifying the nozzles that are less likely to drift during pesticide applications. The flow rate for each nozzle was obtained using a SpotOn spray calibrator. The spray equipment was designed in-house to carry out the experiment. The droplet size and speed were measured via a VisiSize P15 image analyzer. The diameter and speed quantiles were calculated at the 10th, 50th, and 90th volume percentiles. The proportion of spray volume with droplets < 150 µm and < 100 µm and the Sauter mean diameter (d32) were also calculated. ANOVA tables corresponding to the results were also generated to identify the interactions between the nozzle, pressure, and height. The results suggest that the nozzle entry orifice area determines the nozzle flow rate and that the ratio of the nozzle entry orifice to the exit orifice affects the driftable spray volume. The air induction nozzles and nozzle AITTJ60-110025 appear to minimize off-target drift to protect pollinators. Drift guard nozzles DG8002, DG8003, DG8004, Turbo TeeJet nozzle TT11001 and the extended range nozzle AIXR11002 produce moderate driftable size spray volumes, while the remaining nozzles produce high drift. Given the scenario of chemical application and the target application rate, the results from this study can guide stakeholders in identifying the most suitable spray nozzle to minimize off-target drift, improve application efficiency, and protect insect pollinators.