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Soil amendment with biochar is widely used to improve soil fertility and crop productivity. However, its effect on plant nematodes has not been examined properly. The present study investigates the effects of biochar on root knot nematode, Meloidogyne incognitaunder in planta conditions. In pots experiment, biochar (45 g) when paired with oil cakes (15 g) suppressed the M. incognitaand improved the plant growth of tested plant. Significant suppression in nematode infestation in terms of egg masses and eggs by (56.0 and 52.7%) and maximum improvement in plant growth in plant length and dry weight by 74.1 and 63.8%, respectively was observed when combined soil application of biochar and mustard cake was applied in the soil. The effect was least when biochar was applied alone. The study has suggested that biochar amendment along with mustard oil cake can control root knot nematode infestation in lentil.

Root-knot nematodes pose a significant threat to agricultural production all over the world. They are ubiquitous, polyphagous, sedentary endoparasites and belong to genus, Meloidogyne. These biotrophic pathogens establish and maintain an intimate interaction with their host plants. Effectors are crucial for the entry of RKNs to the root of plants, subsequently leading to the formation of the specialized hypertrophied and multinucleate feeding sites for nematode growth and development. During the establishment and maintenance of nematode feeding sites, effectors are considered to play a critical role in the modulation of developmental and defence signaling pathways in host cells. Chemical nematicides are widely used in RKNs management strategies, despite their threat to environmental and human health. Recently, restrictions on using some chemicals have been enforced. So, there is a need of potential environmentally benign strategies to the management of RKNs. We will highlight most the effective strategies viz.,biological control by bacteria and fungi and organic amendment by botanicals and oil cakes. Also taken into account are traditional strategies like cultural method, soil solarization and resistant cultivars. One of the best alternatives to chemical control of RKNs is biological control, which involves the use of predators and parasites to reduce the RKNs at various life stages (eggs, juveniles and adults), as well as the secretion of poisonous diffusible inhibitory metabolites which hamper the reproduction ability of RKNs. Here, we provide a brief review of the biology of the genus, Meloidogyne, plant-nematode interactions and various environmentally benign strategies.

Induced resistance techniques for plant disease management are one of the robust and constructive approaches against plant pests. The present study conducted to trigger the plant-mediated resistance in tomato cv. “K-21” against Meloidogyne incognitaby the involvement of dl-β aminobutyric acid (BABA) under salt stress conditions. Results indicate that seedlings elicitors (dl-β aminobutyric acid) strongly suppressed multiplication of nematode population. At the same time, we could not observe this effect in an inoculated control. Additionally, treated tomato roots with BABA and BABA, coupled with NaCl, showed significant improvement in growth parameters and phenolic compounds. Application of BABA (1.21 mM) + NaCl (100 mM) in combination significantly reduced the root-knot index by 48%. Whereas the same combination significantly improved the phenolic compounds and dry weight content up to 75% and 64% respectively. The minute amount of BABA, in combination with salt stress, resulted in greater efficacy as compared to the higher quantity of BABA (2.42 mM) that might be the cause of synergistic interaction. However, the lowest % increase in phenolic compounds by 60% and decrease of the root-knot index by 40% as we observed in the highest dose of BABA (4.84 mM). Findings of our study suggest that the application of BABA alone and in combination with salt is a promising tactic to inflate the tomato resistance against M. incognitathat might be associated with the enhanced defence response in tomato. Moreover, the stress modulation reaction of BABA under salt stress would be linked with resistance in plants.