Eco-friendly Management of Root Knot Nematode (Meloidogyne graminicola) of Basmati Rice

Abstract

Rice is the most promising cereal worldwide since it provides staple food for more than half of the world’s population. Several biotic and abiotic factors limit the rice productivity. Among the biotic factors, rice root knot nematode (Meloidogyne graminicola) is a major constraint to decreasing rice production. Present investigation was carried out in Nematology lab and field condition for the management of Meloidogyne graminicola. The efficacy of cow urine, neem cake extracts at different concentrations @5%, 10% and 15% were tested against larval mortality and egg hatching of M. graminicola. At 5% concentration, maximum (100%) larval mortality was found in cow urine after 72 hours of inoculation. At 10% and 15% concentration, maximum (100%) larval mortality was found in cow urine and cartap hydrochloride after 72hrs of inoculation. In case of egg hatching inhibition, at 5%, 10% and 15% concentration, minimum egg hatching was recorded in cow urine (43.35%), (33.35%) and (21.65%) respectively after 72hrs of inoculation. In another experiment, efficacy of cow urine was tested in vitro at 5%, 10%, and 15% concentrations on mycelial growth of different isolates of Trichoderma sp. In Trichoderma S13, after 72hrs of inoculation, maximum mycelial growth (9.00cm) was observed at 5% concentration and minimum mycelial growth (6.23cm) was recorded at 15% concentration. In Trichoderma S7, after 72hrs of inoculation, maximum mycelial growth (8.90cm) was observed at 5% concentration and minimum mycelial growth (6.50cm) was recorded at 15% concentration. In Trichoderma S32, after 72hrs of inoculation, maximum mycelial growth (9.00cm) was observed at 5% concentration and minimum mycelial growth (6.17cm) was recorded at 15% concentration. A pot experiment was conducted to test the efficacy of required concentration of cow urine against root knot nematode. Minimum (4.00 galls/ plant) was recorded in (T9) SA of cow urine @25ml at 10 DAS with maximum shoot length (19.00cm), root length (5.67cm) and chlorophyll content (30.67 SPAD Value). Another experiment to test the efficacy of different isolates of Trichoderma viz; S13, S7 and S32 against rice root knot nematode was conducted. Minimum (1.00) galls/plant was recorded in (T11) SA of cartap hydrochloride 4G @ 0.3g a.i. /kg of soil with maximum shoot length (19.33cm) and root length (6.17cm) followed by (1.33 galls/plant) in (T7) SA of Trichoderma isolate S13 @6g/kg of soil + neem cake @20g/kg of soil with shoot length (19.33cm) and root length (5.83cm). Twenty promising rice varieties were screened against rice root knot nematode under pot conditions. Maximum number of galls/plant were recorded in Pusa basmati-1121 followed by Vallabh basmati-22, Vallabh basmati-24 and Pusa basmati-1638 with Root gall index (RGI) = 3. Hence, the present investigation proved that the use of cow urine and an antagonistic fungi Trichoderma is effective in the management of M. graminicola.