Botanical extracts modulate egg hatching, juvenile mortality, and population dynamics of root-knot nematodes in rice seedlings

The root-knot nematode, Meloidogyne graminicola, presents a significant threat to rice Production necessitating sustainable management approaches. This study investigates the nematicidal potential of botanical extracts against Meloidogyne graminicola, a significant pest in rice agroecosystems. Aqueous leaf extracts of Melia azedarach, Phyllanthus amarus, Azadirachta indica, and Tridax procumbens were tested for their efficacy in inhibiting egg hatching and inducing juvenile mortality under laboratory and greenhouse conditions. Results indicated that M. azedarach exhibited the highest nematicidal activity, with up to 90% egg hatching inhibition and 82% juvenile mortality at 1500 ppm after 72 hours. P. amarus and A. indica also demonstrated significant suppression, while T. procumbens showed the least effect. LC₅₀ values decreased over time, highlighting the concentration- and time-dependent efficacy of the extracts. Greenhouse trials further confirmed that M. azedarach significantly reduced root gall formation, egg mass production, and nematode populations. This research emphasizes the potential of botanical extracts as sustainable alternatives to synthetic nematicides, contributing to eco-friendly nematode management in rice cultivation.