Population and Effect of Rice Root Knot Nematode in Diseased and Healthy Looking Rice Plants and Their Distribution in Rice Field

Abstract

A field survey was carried out to discover the population of M. graminicola in diseased and healthy looking rice plants and its impact on yield and yield attributing characters of rice during 2000 in Chitwan, Nepal. Root and soil samples were collected from ten upland rice fields. Modified Baermann Tray Method was used to extract the juveniles (J2) from soil and root samples. The survey revealed that the diseased root samples had the highest Meloidogyne graminicola J2 population. However, the nematode population in root and soil and root knot intensities did not differ significantly between diseases and healthy looking plants. Diseased rice plants had lower number of total and effective tillers, filled grains per panicle and grain yield. Yield reduction in diseased plants was 40.5% as compared to healthy plants in the variety 'Masuli' M. graminicola, even if a new pathogen, seems to be already established in sandy loam to loamy sand soil and reducing rice yield considerably in Nepal.

J. Inst. Agric. Anim. Sci. 23:9-14.