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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.

The current experiment was performed to determine the nematicidal behaviour of aqueous extract of various weed plants viz., Parthenium hysterophorus, Cymbopogon citratus, Eichhornia crassipes, Monstera deliciosa and Tinospora cardifolia against hatching, mortality and penetration rate of Meloidogyne incognita under in vitro condition. The eggs and second stage juveniles were exposed to various concentrations (250, 500, 1000, 1500, 2000 and 2500 µg/ml) for 5 days and 12, 24 and 48 h respectively. During the experiment, all plant extracts displayed nematicidal potential. Comparison of LC50 values of different plant extracts showed that P. hysterophorus was found to be most effective with LC50 664.9 µg/ml, while T. cardifolia was less effective at 48h of LC50 1419.0 µg/ml. Aqueous extracts of P. hysterophorus at 2500 µg/ml was highly effective against hatching and mortality after 5 days and 72h exposure period respectively. Whereas T. cardifolia was found least effective. The macerated leaves of P. hysterophorus applied at 0.3 g/kg sand showed the lowest penetration of M. incognita in brinjal roots while T. cardifolia displayed highest after 3 and 5 days' post inoculation. This study suggests that aqueous extract of the selected plants having nematistatic and nematicidal properties that can be used for the management of M. incognita in an eco-friendly manner and sustainable agriculture. [ABSTRACT FROM AUTHOR]

This study was conducted on tomato (Solanum lycopersicum cv. K-21) to investigate the bioprotective nature of Pseudomonas fluorescens and its interactive effects with Meloidogyne incognita in terms of growth biomarkers, changes in biochemical attributes and modulation in antioxidant enzymes of the tomato plant. In this study, we grew tomato plants with M. incognita and P. fluorescens in separate pots, simultaneously and sequentially (15 days prior or post) after 15 days of seed sowing. The sequential inoculation of Mi15→Pf maximally increased the root-knot index and decreased the nematode population. It was also noted that inoculation suppressed the plant growth biomarkers in comparison to control. However, maximum suppression in nematode reproduction and increment in growth and physiological attributes were observed when P. fluorescens was applied 15 days prior to the nematode (Pf15→Mi) as compared to control. All the treatments showed an increase in antioxidant enzymes. Expression of phenol content and defensive enzymes such as peroxidase (POX) and superoxide dismutase (SOD) increased, in contrast to a significant reduction in malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents when compared with the untreated inoculated plants. However, the highest levels of POX and SOD, and a lowest of phenol, MDA and H2O2 were displayed in the treatment Pf15→Mi, followed by Mi+Pf and Mi15→Pf. [ABSTRACT FROM AUTHOR]