An α-Cyclodextrin and Polyethylene Glycol-Based Hydrogel for Herbicide Delivery under Host–Guest Recognition: Achieving Precise Application and Reduced Environmental Risk by Antidrift Control

Abstract

Glyphosate isopropylamine salt (GIS) is widely used, but spray drift reduces efficacy and threatens nontarget ecosystems. To suppress drift and enhance deposition, we developed a hydrogel (α-CD@PEG@GIS) based on host–guest complexation between α-cyclodextrin and polyethylene glycol. Characterization confirmed successful fabrication. The hydrogel improved foliar adhesion by suppressing droplet splashing. Wind tunnel data revealed that at 4 m from the nozzle, drift volume was 55.7% and 36.6% lower than GIS solution (GISS) and commercial GIS aqueous formulation (GISA), respectively, with reduced deposition in nontarget areas. The hydrogel showed good herbicidal activity against barnyardgrass and biosafety in glyphosate-resistant cotton, and the carrier materials were safe for maize. Overall, this biocompatible system offers antidrift and high deposition, with broad prospects in precision agriculture.