A comparison of modeled spray deposition with measurements in UASS mosquito adulticiding

Authors: THISTLE, HAROLD - Teals, Llc; THISTLE, ANDREW - Mdot Technologies; BONDS, JANE - Bonds Consulting Group; Fritz, Bradley

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: The use of drones to apply mosquito sprays is growing rapidly, but existing models used to predict how sprays move and settle in the environment may not accurately reflect real-world conditions for these unique aircraft and application methods. In this study, researchers compared predictions from the widely used AGDISPpro spray model with actual data collected during drone-based mosquito spraying trials. While the model sometimes predicted spray deposition within acceptable ranges, it often placed droplets too close to the spray line and generally overestimated how much material reached the ground. The research highlighted important limitations in using current modeling tools—especially for very fine sprays released from high altitudes—as well as the challenges of validating a proprietary model without full access to its code. These findings are important for public health programs and regulatory agencies relying on models to assess spray safety and effectiveness. By identifying where the models fall short, this work supports the future development of more accurate, transparent tools for evaluating mosquito control applications conducted with small drones.

Technical Abstract: A comparison is run between deposition data collected downwind of UASS mosquito adulticide spraying and simulated values generated using AGDISPpro. AGDISPpro is a proprietary model. Therefore, to gain insight into UASS modeling, a detailed discussion of current numerical and simulation techniques described in the literature is given. UASS adulticide spraying offers a difficult case for AGDISPpro simulation as very fine droplets are sprayed from relatively small UAVs at greater height than in other application scenarios. The AGDISPpro Lagrangian model often simulates within a factor of two (considered successful) but tends towards over estimation and tends to bring material down closer to the flightline than shown by the data. Data and model limitations are discussed. A longer range model available in the AGDISPpro toolbox using straight-line Gaussian techniques to extend beyond the Lagrangian approach was also included in comparisons.