Star polycation nanocarrier selectively enhances mesotrione control efficacy via reduced particle size and improved...

Nanocarrier-based formulations offer a superior means of enhancing control efficacy and increasing utilization. Star polycation (SPc) was an efficient nanocarrier of insecticides and fungicides. However, whether it could serve as an herbicide nanocarrier needs further study.

Here, we evaluated the nanoformulation, permeability, and herbicidal efficacy of SPc assembled with herbicides. Results showed that SPc could spontaneously assemble with each of the three herbicides via electrostatic interactions. Only mesotrione technical concentrate (TC) and formulation (FM) could be effectively nanosized by SPc, while the particle sizes of atrazine and quizalofop-p-ethyl showed only a marginal decrease. Mesotrione self-assembled with SPc mainly through specific hydrogen bonding, achieving a loading capacity of 38.8%. SPc reversed the zeta potential of mesotrione from negative to positive (with a negligible change in absolute value), reduced the contact angle of TC and FM by 10.5% and 7.8%, respectively, increased the retention on leaves by ranges of 24.3%-65.7%, and significantly enhanced the foliar absorption of mesotrione by 12.4% after treated for 7 days. Compared with the SPc-free treatment, the fresh weight inhibition rates of mesotrione TC + SPc and FM + SPc against Digitaria sanguinalis, Setaria viridis, and Amaranthus retroflexus were increased by ranges of 17.24%-54.05% and 31.32%-39.60%, respectively. The nanosized mesotrione caused no influence on the maize biomass even at 1.5 times the recommended dose (562.5 mg/L).

This study establishes SPc as a high-performance delivery platform for enhancing the bioavailability of certain herbicides, and offers a theoretical basis for the application of SPc as a tank-mix adjuvant in weed management. © 2026 Society of Chemical Industry.