Botanical Biopesticides for Climate Resilient Agriculture: From Phytochemicals to Agroecosystems-A Review

Global agricultural systems face mounting pressure from climate change and insect pest damage, which destroys 20–40% of global crop production annually. Synthetic chemical pesticides, the conventional response, have incurred high ecological costs through environmental contamination, toxicity to non-target organisms and the rapid evolution of resistance in pest populations. Botanical biopesticides, derived from the rich phytochemical arsenals of medicinal plants, offer a scientifically validated alternative for building climate-resilient agricultural systems. This review synthesises current knowledge on three critical dimensions: (1) the chemical complexity of plant secondary metabolites, including terpenoids, alkaloids and phenolics, which confer multi-target mechanisms of action against pests; (2) advanced formulation technologies such as microencapsulation and nano-formulations that enhance field persistence and climate resilience; and (3) strategic integration into integrated pest management (IPM) systems for insecticide resistance management. Evidence demonstrates that botanical biopesticides, when formulated and deployed strategically, provide broad-spectrum efficacy across insect pests, fungal pathogens and nematodes. Significant barriers, including climate-driven variability in phytochemical composition, inherent instability under environmental stressors and regulatory frameworks designed for single-molecule synthetics, currently limit widespread adoption. A coordinated advance across molecular biology, formulation science and regulatory reform is essential to realise the full potential of botanical biopesticides in sustainable, climate-adaptive agriculture.