Interactions of foliar nanopesticides with insect cuticle facilitated through plant cuticle: Effects of surface chemistry and roughness-topography-texture

In response to the growing worldwide demand for enhanced agricultural output and sustainable farming practices, nanopesticides have become a significant area of investigation in agricultural research. Importantly, the fate, distribution, and efficacy of any nanopesticide is linked to the interfacial attributes and dynamic interactions between the outer surfaces – cuticle – of plants and insects. This review starts with an outline of the diverse pathways facilitating the accumulation of nanopesticides on plant cuticles, including their eventual transfer to the cuticles of insect pests. Subsequently, a comprehensive overview is provided of the micro- and nano-scale morphological features characteristic of plant and insect cuticles, along with the implications these features hold for their interactions with various nanopesticides. The review then focuses on interactions between nanopesticides and insect cuticles mediated through the plant cuticle. Finally, nanoscale mechanistic processes are discussed, with an emphasis on aspects such as wetting dynamics, critical length scales (e.g., inter-crystal spacing of waxes and surface wavelengths), and interdigitation and molecular adhesion processes of long-chain and macromolecular nanocarriers. Collectively, the review elucidates the essential interfacial processes governing the transfer and adhesion of nanopesticides between entities. The concluding section provides an overview of the prevailing challenges and potential avenues for understanding the transport and deposition mechanisms of nanopesticides to plants and insects.