Occurrence and distribution of plant-parasitic nematodes associated with rice in the south-eastern Agro-climatic Zone (IIIA) of Bihar, India.

Rice (Oryza sativa L.) is a major staple cereal crop that sustains nearly two-thirds of the global population, particularly in Asia. India is one of the leading producers and consumers of rice, with the state of Bihar playing a significant role in national rice production. However, rice productivity is constrained by several biotic and abiotic factors, among which plant-parasitic nematodes (PPNs) represent an important yet often overlooked limitation. Rice grown under waterlogged conditions is vulnerable to infestation by various PPNs, resulting in substantial yield losses. The present study was conducted to assess the occurrence, distribution, and community structure of PPN's associated with rice cropping systems across six districts of agro-climatic zone IIIA of Bihar. Nematodes were extracted from both root and soil samples and analyzed for population density and community parameters. The results revealed that Meloidogyne spp. were the pre-dominant nematodes in both root and soil samples. Community analysis further demonstrated that the frequency, density, and dominance of the root-knot nematode (Meloidogyne spp.) were significantly higher than those of other PPNs in the rice ecosystem. These findings highlight the widespread prevalence of Meloidogyne spp. in rice fields of Bihar and provide a scientific basis for developing region-specific nematode management strategies to enhance rice productivity.