Volatile organic compounds and individual compounds of Asarum sieboldii roots exhibit fumigant activity against Meloidogyne incognita

BACKGROUND: Root-knot nematodes (Meloidogyne incognita) pose a persistent threat to global agriculture. The widespread use of chemical nematicides for their controlling has raised environmental safety and human health concerns, highlighting the urgent need for sustainable and eco-friendly alternatives. Asarum sieboldii, a medicinal plant with documented bioactive properties, is a potential source of eco-friendly biocontrol agents. In this study, the nematicidal efficacy of A. sieboldii root volatile organic compounds (VOCs) against M. incognita was evaluated, and the mechanisms underlying the reduction in the number of root galls and egg masses by VOCs was elucidated. RESULTS: VOCs from A. siebedii roots exhibited significant nematicidal activity, causing 76.31% and 96.89% mortality of second-stage M. incognita juveniles after 24 and 48 h, respectively, and effectively inhibited egg hatching by 72.94%. Activated carbon adsorption experiments confirmed VOCs as the primary bioactive agents. VOCs reduced the number of root galls and egg masses in tomato. We identified and screened three effective VOCs, namely 3,5-dimethoxytoluene, 4-methoxyacetophenone and β-pinene, that exhibited direct-contact and fumigant activity, and outperformed the commercial nematicide dazomet, reducing root galls on tomato by 65.5%, 55.3% and 44.4%, respectively, while enhancing the growth. These compounds triggered the accumulation of reactive oxygen species in nematodes, leading to oxidative stress and concurrent inhibition of peroxidase and catalase activities. CONCLUSIONS: Three compounds from A. sieboldii exhibited fumigant activity against M. incognita and promoted tomato growth, highlighting their dual advantage over traditional chemical nematicides. These findings should contribute to the development of plant-based, environmentally-friendly strategies for integrated pest management. © 2025 Society of Chemical Industry.