MSc

The objectives of the study entitled ‘Management of root knot nematode in rice’ was to identify the species of rice root knot nematode and to study the management of this nematode by different bio agents, chemical pesticides and a neem formulation. A survey was conducted for the collection of soil and root samples from the rice growing tracts, already infected with root knot nematodes. The species of root knot nematode attacking rice plant was identified as Meloidogyne graminicola Golden and Birchfield.

Pot culture experiments were conducted to study the management of rice root knot nematode under flooded and non flooded condition by different bio agents, chemicals and a neem formulation The effect of the treatments on the shoot characters, yield, root characters and nematode population were tested.

Seed treatment with B. subtilis, P. fluorescens, T. viride and P. fluorescens + T. viride produced more vigorous seedlings with more number of leaves and height compared to other treatments. At the time of harvest also B. subtilis was superior. All other treatments except carbosulfan showed significant effect on the number of leaves, tillers and height of the plant.

In non flooded condition, B. subtilis followed by AMF and carbofuran showed superior effect in terms of root characters (length and weight of roots). In flooded condition also B. subtilis showed its superior effect. This was closely followed by AMF, carbofuran and P. fluorescens. Carbosulfan was the least effective treatment in both the conditions. Control plants showed poor root growth with only very short roots.


The yield attributes (days to flowering, days to harvest, number of panicles, number of grains per panicle, wet weight of grains, dry weight of grains and straw weight) in both flooded and non flooded conditions were superior in plants treated with B. subtilis. This was followed by carbofuran, AMF and P. fluorescens in non flooded condition and AMF, carbofuran, P. fluorescens and neem granules in flooded condition. There was no effect for enhancing the yield characters by carbosulfan. Plants in control pots were dwarf with only less number of leaves and tillers.

The nematode population characters with reference to reduction in number of nematodes in soil and root and gall count in root was superior in carbofuran treated plants in non flooded condition with 99.08, 99.26 and 97.50 percent reduction over the control respectively. B. subtilis treated plants showed superiority in flooded condition with 98.36, 98.79 and 95.56 per cent reduction over the control. There was statistically significant reduction in nematode population in all the other treatments (AMF, P. fluorescens, neem granules, T. viride and P. fluorescens + T. viride) except carbosulfan.