Development and characterization of Artemisia argyi essential oil-loaded nanoemulsion for sustainable weed control: Enhanced stability, amplified activity, protected non-target

Nanotechnology contributes to the development of biopesticides with reduced toxicity, increased stability, improved biosafety, and higher activity against targets. It has demonstrated great potential as a solution for practical applications of essential oils. Herein, the HLB method developed two Artemisia argyi essential oil-loaded nanoemulsions (AEOnano). Further systematically optimizing the ratio led to small droplet size (<200 nm) and low PDI (<0.3). As anticipated, the AEOnano demonstrated robust physical stability when subjected to various stressors. Notably, both indoor and outdoor pot experiments demonstrated that AEOnano outperformed ordinary A. argyi essential oil aqueous emulsions (AEOAE) in weed control. These nanoemulsions allowed a 2-4 times reduction in AEO dosage while maintaining the same weed-killing efficacy. The superior improvement attributed to the nanoemulsions enhanced leaf-wetting capability, improved leaf retention, and resistance to wash-off. In addition, biosafety assessment indicated that AEOnano did not affect the plants (Artemisia argyi, Chrysanthemum morifolium, cotton), which provide orientation for its practical application. Therefore, this study introduces a promising approach to enhance the effectiveness of AEO-based herbicides, which will have a broad application prospect in sustainable agriculture.