EFFECT OF DIFFERENT CROPPING SEQUENCES ON ROOT-KNOT NEMATODE, MELOIDOGYNE GRAMINICOLA, AND YIELD OF DEEPWATER RICE
AbstractThe rice root knot nematode, Meloidogyne graminicola Golden et Birchfield, is an important pest in deepwater rice (DWR) in Bangladesh. Several cropping sequences were followed in an infested field to investigate their effects on M. graminicola and yield of DWR. Crops included in the sequences were mustard (Brassica campestris subsp. oleifera L.), sesame (Sesamum indicum L.), millet (Setaria italica L.), guzitil (Guizotia abbysinica L.F.), khesari (Lathyrus sativus L.) and marigold (Tagetes patula L.). Numbers of M. graminicola juveniles were reduced by 85% when mustard and guzitil were mixed sown in winter followed by mixed sowing of DWR with sesame. There was 65% reduction when mustard was grown alone followed by DWR mixed with millet. Reductions of 18 and 14% were obtained when khesari and mustard respectively preceded DWR. Although different cropping sequences did not affect the yield of deepwater rice, the total economic return in a year was the highest in mustard + guzitil followed by DWR + sesame cropping sequence.