Title : Harnessing potential of deoiled seed cakes for the management of phytonematodes
Abstract:
Plant-parasitic nematodes (phytonematodes) are responsible for annual crop losses exceeding US$125 billion worldwide and continue to threaten food security by reducing crop productivity and quality. Although synthetic nematicides provide effective control, their increasing regulatory restrictions, environmental concerns, adverse effects on non-target organisms and mostly expensive have accelerated the search for sustainable alternatives. Among various organic amendments, deoiled seed cakes, the nutrient-rich by-products obtained after oil extraction from oilseed crops, have emerged as promising bio-based inputs for cost effective integrated phytonematode management in crops. This review critically compiles and synthesizes more than six decades (1960–2026) of research conducted in India on the utilization of deoiled seed cakes against economically important phytonematodes. The review integrates evidence from peer-reviewed publications, institutional reports and M.Sc. and Ph.D. theses. Major deoiled seed cakes evaluated include neem (Azadirachta indica), mustard (Brassica juncea), castor (Ricinus communis), karanj (Pongamia pinnata), groundnut (Arachis hypogaea), sesame (Sesamum indicum), mahua (Madhuca longifolia), cottonseed, linseed, and other indigenous oilseed residues. Their effectiveness has been documented against Meloidogyne spp., Rotylenchulus reniformis, Pratylenchus spp., Radopholus similis, Tylenchorhynchus spp., Hoplolaimus spp., and several other economically important nematodes in vegetable fields, fruits, plantation, spice, medicinal and ornamental crops. The compiled evidence demonstrates that neem and mustard deoiled cakes consistently provide superior nematode suppression through the release of ammonia, glucosinolate-derived isothiocyanates, limonoids, phenolics, and other bioactive compounds generated during decomposition. Besides direct nematicidal activity, these amendments also improve soil organic carbon, nutrient availability, microbial diversity, root development and plant health while stimulating beneficial microorganisms that contribute to biological suppression. Integration of deoiled seed cakes with biological control agents, including Purpureocillium lilacinum, Pochonia chlamydosporia, Trichoderma spp. and Pseudomonas fluorescens has consistently resulted in enhanced nematode suppression and constantly improved crop productivity compared with individual treatments. The review further identifies critical research gaps concerning standardization of deoiled seed cake quality, optimization of application rates, characterization of bioactive metabolites and validation under protected cultivation, climate-resilient agriculture and natural farming systems. The available evidences indicate that deoiled seed cakes constitute an environmentally safe, economically viable and scientifically validated component of sustainable phytonematode management, offering significant potential to reduce dependence on synthetic nematicides while improving soil health and agricultural sustainability.
