Biocontrol-mediated alleviation of root-knot nematode-induced stress in groundnut (Arachis hypogaea L.): Effects on plant growth and yield

Management of root-knot nematode remains a major challenge in organic farming, where synthetic nematicides are avoided. A pot culture experiment was conducted at the College of Agriculture, Odisha University of Agriculture and Technology, Chiplima, during 2023–24 to evaluate the efficacy of different biocontrol agents and neem oilcake against Meloidogyne incognita in groundnut cv. Kalinga Groundnut-101 under organic production. Six treatments were evaluated in a completely randomised design with 5 replications. Biocontrol treatments significantly improved plant growth, yield and reduced nematode infestation compared with the inoculated check. T₃ (Rhizobium spp. + Paecilomyces lilacinus) recorded the highest numerical values for plant growth, chlorophyll content and biomass, whereas T₁ (Rhizobium spp. + P. lilacinum + Trichoderma harzianum) produced the highest yield, root nitrogen and crude protein content. Among the biological treatments, T₂ (Rhizobium spp.+ T. harzianum) reduced root galls by 30.00 %, while T₃ reduced the soil nematode population by 14.96 % over the inoculated check. Overall, the integrated application of Rhizobium spp. with biocontrol agents showed promising potential as an eco-friendly alternative for improving groundnut growth and suppressing root-knot nematodes under pot conditions, although field validation is required before large-scale recommendation.