Nematode problems of rice in India

Abstract

Abstract Many species of nematodes were reported in association with rice culture in India. The potential of a few stylet‐bearing plant parasitic nematodes as pests of rice has been investigated. Among those affecting the foliage, the white‐tip nematode Aphelenchoides besseyi is widely prevalent but severe in Southern and Eastern States causing yield losses of up to 20%. The stem or ufra nematode Ditylenchus angustus is restricted to the Northeastern States, Assam and West Bengal, inflicting losses of up to 30% Among the root infesting forms, the rice root nematodes, Hirschmanniella spp., prevail throughout the country in varying densities but the damage depends upon the density of the nematode populations in relation to the stage of the crop growth. These pests are endemic in multicropped rice areas and can cause 40% losses. The root‐lesion nematode, Pratylenchus indicus and lance nematode, Hoplolaimus indicus are common in uplands and in areas where other cereals are grown in rice based cropping system, causing losses up to 28% and 18% respectively in rice. Of special importance among the soil borne nematodes are the root‐knot nematode, Meloidogyne graminicola and cyst nematode, Heterodera oryzicola which can cause up to 21% and 38% yield losses respectively in rainfed or well drained soils throughout the country. The distribution, endemic areas and symptoms of damage and problems in rice due to these and other parasitic nematodes of rice are discussed.