Development of a performance-matched oxaziclomefone nanosuspension based on the hydrophobic surface characteristics of barnyardgrass for unmanned aerial vehicle sprayers to improve herbicidal activity in direct-seeded rice fields

The explosive increase in the use of unmanned aerial vehicle (UAV) sprayers has put forward new requirements for pesticide formulations, and there is an imperative necessity to develop targeted, precise, and efficient pesticide formulations based on the surface characteristics of targets to meet the demand for low-volume spraying by UAVs. Herein, a performance-matched oxaziclomefone nanosuspension (NS) was constructed based on the hydrophobic surface characteristics of barnyardgrass for UAV sprayers. The results showed that the solid surface free energy of the adaxial and abaxial surfaces of barnyardgrass at different growth stages ranged from 23.73 to 28.00 mJ m^–2 and was dominated by dispersive components. The average sizes of micro-nanostructures on the barnyardgrass surfaces ranged from 251.7 to 266.8 nm, and the oxaziclomefone nanoparticles in the NS could be suitably embedded into the micro-nanostructures of the barnyardgrass surface. The atomization test showed that the NS could significantly decrease the percentage of spray droplets with sizes for droplet drift. Due to the precise regulation of the formulation components, the NS exhibited superior wetting, spreading, and adhesion performance on the barnyardgrass surface. Moreover, the NS remarkably enhanced the uptake and translocation of oxaziclomefone in barnyardgrass. Field trials showed that, compared to the commercial formulation, the NS could significantly improve the control efficacy against barnyardgrass in direct-seeded rice fields while demonstrating acceptable safety for rice. Our research provides a novel, promising, and feasible strategy for the development of pesticide formulations based on target surface characteristics and for improving the physicochemical properties of dilutions, which is valuable for enhancing dosage delivery efficiency and improving control efficiency against pests for UAV sprayers.