The Meloidogyne or root-knot species are obligate endoparasites having a wide range of hosts including rice. Meloidogyne graminicola is the most widely distributed serious nematode pest of the rice in India and has been considered economically important next to Hirschmanniella spp. The commonly found species in India, M. graminicola does not produce galls on rice roots growing in flooded soils but may survive within roots for about five weeks. Groundnut, sweet potato, maize, soybean and many other crops have been confirmed as non-host crops for M. graminicola. The root-knot infestation of rice is mainly found in upland regions because the nematodes are poorly adapted to flooded conditions. Since the root-knot nematodes are poorly adapted to the flooded conditions, flooding the fields by irrigation water for more than 30 days also brings down the Meloidogyne population and increases the yield significantly.