Advancing plant-origin bioactive compounds as nematicides –present insights and future directions

Abstract

Plant parasitic nematodes (PPNs) are a major challenge to agricultural productivity, causing global crop losses. Although chemical nematicides are still widely used due to their cost-effectiveness and immediate availability, concerns over their environmental and health risks have driven the search for eco-friendly alternatives. Plants with nematicidal properties have emerged as a sustainable option, leading to the development of botanical nematicides. However, large-scale production is constrained by the limited availability of plant material and extracts, prompting efforts to identify plant-origin bioactive compounds (POBCs) with nematicidal potential. Plant-origin bioactive compounds offer several advantages, including reduced toxicity to non-target organisms, environmental safety, and potential for integration into sustainable pest management practices. Over the past two decades, around 114 POBCs from 20 plant families have been identified, including flavonoids, isothiocyanates, saponins, coumarins, terpenes, alkaloids, ketones, glucosinolates, phenolic compounds, phthalides, limonoids, and glycosides. These compounds exhibit nematicidal, nematostatic, membrane-disruptive, egg hatch inhibitory, and developmental inhibitory effects against key PPN species such as Meloidogyne spp., Pratylenchus spp., and Heterodera spp. Effective doses for nematode control range from 11.7 to 188.3 mg/L, 3.2–500 μg/mL, 0.125–1.0 %, and 25–50 ppm. Commercial POBCs like azadirachtin, thymol, and geraniol are marketed globally, though challenges in raw material availability, extraction, and standardization remain. Bioinformatic tools and advanced formulation technologies, such as nanoemulsions and solid lipid nanoparticles, are being explored to enhance the efficacy and stability of POBC-based nematicides. This review highlights the progress in POBC research, their mechanisms of action, and emerging strategies to overcome production and formulation challenges for sustainable nematode management.