Reduction of pesticide dosage and off-target drift with enhanced control efficacy in unmanned aerial vehicle-based application using lecithin adjuvants.

Background: Unmanned aerial vehicles (UAVs) are increasingly used in precision agriculture, particularly for pesticide application in rice cultivation. One challenge is off-target pesticide drift, which raises environmental concerns and reduces pesticide efficiency. Lecithin adjuvants have been suggested to enhance droplet stability, reduce drift, and improve control efficacy. This study aims to evaluate the efficiency of lecithin adjuvants in reducing pesticide drift and improving deposition during UAV-based pesticide application under various paddy field conditions.

Results: The addition of 1% lecithin adjuvants in 75% dosage of tricyclazole and ferimzone dual active ingredient formulations reduced off-target drift by 2.62 to 3.16 times compared to the 100% and 75% dosage of standard formulations, with deposition efficiency along the spray path increasing by up to 155%. Wind direction and speed were found to be the primary environmental factor affecting deposition efficiency and drift rate. The control efficacy against leaf blast disease was significantly improved, with a maximum efficacy of 73.7% observed in the adjuvant-treated group. Initial pesticide residues on rice plants were the highest in treatments with adjuvants, but their harvest products, brown rice and dried straw, were still within safe limits for human consumption.

Conclusion: Lecithin adjuvants significantly reduce off-target drift and enhance pesticide deposition during UAV-based application. This method allowed for lower pesticide dosages without compromising control efficacy, contributing to more sustainable agricultural practices. These findings highlight the potential of adjuvants to improve UAV pesticide application and reduce the environmental impact of pesticide use. © 2024 Society of Chemical Industry.