Devi, GitanjaliBhuyan, Prerana2024-07-112024-07-112023https://krishikosh.egranth.ac.in/handle/1/5810211829A survey of plant-parasitic nematode, Rotylenchulus reniformis Linford & Oliveira, 1940 was carried out at the Experimental field of Department of Horticulture, AAU, Jorhat during Rabi and Kharif season, 2022-2023. Analysis of 200 soil and root samples collected from the root rhizosphere of different vegetable, fruit and ornamental crops showed the presence of Rotylenchulus reniformis with 54.2% Frequency of occurrence with 123 mean population density/ 250 cc of soil in vegetable crops, 40.0% Frequency of occurrence with 86 mean population density 250 cc of soil in fruit crops, and 35.0% Frequency of occurrence with 59 mean population density 250 cc of soil in ornamental crops. Pathogenicity of reniform nematode, R.reniformis, was investigated on tomato var. Pusa Ruby by inoculating 10, 100, 500, 1000, 5000 and 10000 nematodes per kg autoclaved soil in root zone of 10 days-old plants. Observations on growth parameters of plants and nematode numbers were recorded at 60 days following inoculation. There was a progressive decrease in the plant growth parameters as the inoculum level of R. reniformis increased. Significant reduction in growth parameters were recorded at 1000 and above nematodes/kg soil. There was a gradual increase in the number of females, egg masses per root system, and nematode population of R. reniformis as the inoculum level increased. The rate of multiplication decreased with increase in the level of inoculation. The threshold level of R. reniformis was found to be 1000 nematodes per kg soil. Investigations were carried out to evaluate the efficacy of two chemical viz., Fluensulfone and Fluopyrum for the management of R. reniformis on tomato (var. Pusa Ruby) under net house condition. All the treatments with chemicals differed significantly from the untreated control. The maximum plant growth parameters in tomato var. Pusa Ruby were recorded in the treatment with Nimitz® (Fluensulfone) @2.5kg/ha followed by, treatment with Carbofuran CG @3.0 kg a.i./ha, treatment with Velum Prime (Fluopyrum) @1000 ml/ha, and treatment with Nimitz® (Fluensulfone) @2.00 kg/ha , treatment with Velum Prime (Fluopyrum) @750 ml/ha. The chemicals suppressed nematode reproduction as indicated by the lower nematode population and lower numbers of eggs found on the roots of tomato as compared to control. The minimum populations of R. reniformis were recorded with the treatment Nimitz® (Fluensulfone) @2.5kg/ha followed by treatment with Carbofuran CG @3.0 kg a.i./ha, treatment with Velum Prime (Fluopyrum) @1000 ml/ha, treatment with Nimitz® (Fluensulfone) @2.00 kg/ha , treatment with Velum Prime (Fluopyrum) @750 ml/ha.EnglishThesis