Effectively enhancing topical delivery of agrochemicals onto plant leaves with nanocelluloses

Topical spray of agrochemical formulations is a convenient and popular approach to protecting the plant and enhancing the crop yield. However, agrochemical utilization efficiency remains relatively low due to the runoff of sprayed drops from leaves. To address this issue, we developed cellulose-incorporated formulations to enhance droplet adhesion and mitigate the runoff. We examined the effect of surface functionalities and morphologies of the nanocelluloses on water retention across three plant species. Remarkably, nanocelluloses significantly enhanced water retention on the foliage, with up to 200-300% increase in the amount, primarily attributed to the increased viscosity and improved wettability on leaf surfaces. The practical implications were demonstrated by the substantial increase in topical delivery of three model pesticides on chickpea leaves, ranging from 70% to 150%. Moreover, the nanocellulose-based formulations after drying on the cotton leaf surface effectively resisted wash-off during moderate rainfall. These formulations are compatible with existing spray facilities, and thus would offer significant economic and environmental benefits for topical delivery of pesticides, potentially revolutionizing the agricultural spraying industry. Nanocellulose-contained suspensions significantly enhance the wettability of three plant leaves, increase the water adhesion onto the foliage, improve topical delivery of three model pesticides, and effectively resist rain wash-off from leaves.