Alpha-terthienyl (A novel marigold derivative): An overview on nematicidal potential

Alpha-terthienyl (α-T), a plant-derived compound primarily found in the root exudates and leaves of marigold (Tagetes spp.), has shown strong potential as a sustainable alternative to chemical nematicides for managing plant-parasitic nematodes (PPNs) such as Meloidogyne, Heterodera and Pratylenchus species. Acting as a phototoxic agent, α-T generates reactive oxygen species (ROS) under ultraviolet (UV) light, leading to nematode mortality through oxidative stress. Its broad-spectrum efficacy, persistence in the rhizosphere and low toxicity to non-target organisms make it a promising candidate for integrated pest management. Studies indicate that α-T induces high mortality in Caenorhabditis elegans and Meloidogyne incognita, disrupts key metabolic enzymes like cholinesterase and glucose-6-phosphate dehydrogenase and exhibits strong photo-larvicidal effects in Aedes aegypti (LC₅₀: 0.002 ppm under UV light), as well as insecticidal activity against Lepidoptera and fire ants. Future research should aim to improve its formulation for field stability, explore synergistic effects with other biopesticides, investigate resistance mechanisms and assess its broader applicability in pest and vector control.