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Aqueous and ethanol extracts of Avicennia marina (Forsk.) Vierh. plant parts, namely leaves, stem and pneumatophore, were tested for their nematicidal activity against root knot nematode Meloidogyne javanica (Treub) Chitwood. Results showed that A. marina exerted more lethal effect in mortality of juveniles compared to hatching of juveniles. Stem showed more nematicidal effect compared to leaves and pneumatophore in aqueous extract, whereas pneumatophore showed more nematicidal activity in ethanol extract. Soil amendment at the rates of 0.1, 1 and 5% w/w was carried out with dried powder of leaves, stem and pneumatophore of A. marina for the control of root knot nematode on mash bean and okra plants. The results pertaining to seed germination percentage, shoot length, root length, shoot weight and root weight showed improvement with maximum inhibition in root knot indices in both mash bean and okra when A. marina plant parts, namely leaves, stem and pneumatophore powder, were used at 5% w/w. Maximum root and shoot weight were observed in mash bean when A. marina plant parts powder was used at 5% w/w. All plant parts of A. marina powder were effective in the control of root knot nematodes.

Rhizosphere soil of mangrove plants (Avicennia marina, Rhizophora mucronata, Aegiceras corniculatum, and Ceriops tagal) was collected from coastal areas. Almost all samples showed a sandy to sandy loam texture. pH of the soil samples ranged from 7 to 10 and water content ranged from 8% to 9%. In all, 18 species of fungi belonging to 11 genera were isolated from the rhizosphere soil of all the mangrove species by direct plating method, whereas 20 fungal species belonging to 11 genera were isolated by serial dilution. Results showed that the greatest number of fungi was isolated by serial dilution. The maximum number of species was obtained from the rhizosphere soil of A. marina, whereas the lowest number of fungi was obtained from the rhizosphere soil of A. corniculatum.