Incidence of Nematode Diseases in Makhana and their Possible Control in Katihar District of North Bihar

Euryale ferox Salisb. commonly known as makhana is an important aquatic annual seed propagating cash crop in shallow water bodies in north Bihar and lower Assam regions of India. On account of being fatless, aphrodisiac, spermatogenic and with high carbohydrate and protein contents, makhana is in high demand in western and gulf countries. Plant parasitic nematodes causes a considerable damage to agricultural crops. Rhizospheres of makhana plant arealso infected by several nematodes which cause a significant loss in crop production. Very little information is available on the parasitic nematodes of makhana crop. In a nematological study conductedin Katihar district of North Bihar altogether 6 species of nematodes belonging to 6 genera associated with rhizospheres of makhana were identified. Hirschmanniella oryzae were the most abundant species dominatingother nematodes in all the months and seasonswithan average of 238 per 100g soil. Maximum population density of nematodes was recorded during September to October and minimum during January to February. In reducing the population of nematodes use of different plant leaves such as Azadirachtaindica, Carica papaya, Thevetia peruviana, Tinospora cordifolia and Ricinus communis were found effective in makhana cultivated ponds. Herbal leaves were found to be more effective in controlling nematode population as compared to nematicide which in turn affects the production of fish in integrated culture.