Nanopesticides in plant protection: Potentials, mechanistic insights, and future perspectives against phytopathogens and insect pests

The majority of pesticides are produced chemically, which might have unforeseen consequences such as excessive energy consumption, pollution, and risks to the environment and human health. Plants are emerging to be a viable, more sustainable source for the biosynthesis of nano-pesticides on a large scale. In a quick and stable single-step green synthesis process, metal ions can be bio-reduced into nanoparticles (NPs) using phytoconstituents. Nano-pesticides are more accessible, less costly, and cause less pollution while also improving environmental and human safety. Nowadays, nano-pesticides can be used to control a variety of plant pests, including bacteria, fungi, and insects. The mechanism of action of nano-pesticides affects the integrity and coloration of the cuticle, triggers immunological reactions, alters gene expression internally, and induces cellular toxicity that impairs the insect's growth and reproduction. Due to the release of reactive oxygen species and the change in their metabolic activity, insects are rendered impaired. Nanoparticles can break down the cell wall and membrane of phytopathogens, prevent spores from germinating, and interfere with bacterial replication. So, their effects go beyond only insects, and they play a big role in methods for managing both pests and diseases. This article spans research from various fields, including phytopathogens and insect pest control, plant-derived pesticides, and nano-pesticides. In terms of pest management in crop systems, this review acts as a thorough compilation, covering topics such as plant-based pesticides, green-synthesized nano-pesticides, innovative pest management strategies, NP-pest interactions, mechanisms of action of nano-pesticides, and their limitations. It highlights the ability to connect the dots between existing literature and ongoing research initiatives, with a wide range of applications for validating the use of plant extracts for pest management and developing plant-based nano-pesticides that are successful, secure, and sustainable for the environment, and widely utilized.