Biological Control of Rice Root-Knot Nematode, Meloidogyne graminicola in Transplanted Rice

The current study is designed for the management of rice root-knot nematode, Meloidogyne graminicola in rice (Oryza sativa L.) under laboratory, nursery and field conditions. Under laboratory conditions, all the substances viz., phytotherapeutic substances, rhizobacteria and chemicals inhibited the juvenile mortality of M. graminicola at all dilution levels at each interval of exposure periods. Among the rhizobacterial strains and plant extracts, the maximum juvenile mortality was observed in Azotobacter chroococcum (HT 54) which is statistically at par with aqueous extracts of Azadirachta indica and only 65.2 and 61.8% juvenile mortality was observed in this case, respectively. However, A. chroococcum, A. indica and carbosulfan gave maximum mortality at 1:5 and 1:10 dilutions irrespective of period of exposure. Under nursery conditions, treatments of neem cake @ 50g/pot (5 kg soil capacity) in combination with Pseudomonas fluorescens @ 50 g/pot significantly reduced the nematode reproduction and multiplication and improved the plant growth parameters of rice (var. PB 1121). In main field experiment, where treated nursery treatments were integrated with main field treatments, significantly highest and maximum yield (51.25 q/ha) was obtained in combination of treated nursery (neem cake @ 50g/pot+ P. fluorescens @ 50 g/pot) and two deep summer ploughing during the month of June also significantly reduced the nematode reproduction and multiplication. So, combination of treated nursery with neem cake and P. fluorescens along with deep summer ploughing in the main field before transplanting has reduced the nematode population and enhanced rice yield.