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The present investigation was carried out to evaluate the potential of chitosan alone and in combination with various agricultural wastes for the management of rootknot nematode, Meloidogyne incognita on eggplant cv. ‘BR-112’ under greenhouse conditions. The results showed that chitosan as a single or joint treatment with agricultural wastes significantly (p ≤ 0.05) reduced root-knot indices, and the nematode population in soil. As a result, of this, the growth and growth yielding attributes of eggplant were remarkably augmented. Chitosan as an elicitor induced plant mediated systemic resistance against M. incognita in eggplant. The results of the study demonstrated that maximum reduction in eggmass/root, eggs/eggmasses, nematode population and root-knot indices, was acquired by the treatments: chitosan + onion and chitosan + mentha. It was followed by chitosan + Brassica, chitosan + urad and chitosan + coconut whereas, chitosan combined with corn cob waste was found to be the least effective when compared to the control. The application of chitosan alone was effective but not very satisfactory. Compared to the control applications of all the treatments significantly increased plant growth in terms of length, fresh and dry weights, pollen fertility, yield and biochemical parameters such as chlorophyll, carotenoid content and antioxidant enzymes. This may have been due to the eliciting activity of chitosan, causing systemic resistance in the plant and the release of various toxic chemical compounds during decomposition which have lethal effects against the second stage juveniles of M. incognita and nematode multiplication.

Root-knot nematode, Meloidogyne incognita (Kofoid and White) is one of most damaging pathogen of vegetables, including carrot (Daucus carota L.). We evaluated nematicidal potential of chitosan in combination with chopped leaves of Argemone mexicana L., Achyranthes aspera L., and Ricinus communis L. against infestation caused by M. incognita on carrot under both in vitro and in vivo. Infectious stage (J2s) and egg masses of M. incognita were exposed to different concentrations (2500, 2000, 1500, 1000, and 500 ppm) of chitosan and botanical extracts separately. Maximum mortality of J2s and the highest inhibition in egg hatching was observed at 2500 ppm of chitosan after 36 h and days incubation period, respectively and minimum found in 500 ppm of A. aspera after 12 h of incubation period. Furthermore, pots treated with 1 g chitosan and 30 g of freshly chopped leaves of all three tested botanicals significantly reduced pathological parameters and improved growth and photosynthetic attributes of carrot. In combination with botanicals, chitosan showed a synergistic effect against M. incognita on carrot as compared to chitosan alone. This study proves that chitosan's bio-efficacy, combined with selected three botanicals, could be utilised to manage M. incognita on the carrot as a potential sustainable treatment. [ABSTRACT FROM AUTHOR]