Plant-Parasitic Nematodes in Indian Agriculture: Assessing Evidence for Crop Losses, Species Assemblages, Diagnostic Capacity, and Management Interventions

Abstract

Plant-parasitic nematodes are a persistent yet inconsistently quantified biotic constraint in Indian cropping systems. National estimates of nematode-related crop losses are frequently cited in the Indian literature and provide a useful perspective on the importance of the problem. At the same time, there has been limited discussion of the methodologies and data sources used to generate these estimates. This review assesses the available evidence on plant-parasitic nematodes in Indian agriculture, focusing on four interconnected areas: crop loss estimation, changes in damaging species assemblages, diagnostic capacity, and the evidence supporting management recommendations. Literature published between 2001 and May 2026 was identified through openly accessible bibliographic indexes and metadata registries, supplemented by backward citation tracking from recent reviews and by verification of bibliographic identity against publisher and registry records. The review indicates that the most commonly cited national loss estimate is derived from the data collected through coordinated research programmes. Much of the supporting field evidence comes from nematicide-based paired-plot studies, which have been valuable for assessing crop responses and estimating the contribution of nematodes to yield loss. Further, contemporary nationwide surveys could complement these efforts by providing updated information on the distribution, incidence, and economic impact of plant-parasitic nematodes across diverse cropping systems. The species assemblage associated with economic damage appears to be changing, with the rice root-knot nematode gaining importance in irrigated and aerobic rice systems and a virulent root-knot species being reported from an increasing range of hosts. Current evidence is based largely on localized surveys and species reports, highlighting the need for broader and repeated assessments to better understand distribution patterns and changes over time. Diagnostic capacity remains an important component of effective nematode surveillance and management. Morphological identification can be challenging for closely related species, while molecular and community-profiling approaches provide improved resolution but are currently available in a limited number of laboratories and require standardised methodologies. Management research has generated substantial information across a range of interventions, although much of the available evidence is derived from pot studies and short-term field evaluations. Future priorities include standardised loss assessment, distributed diagnostic capacity, and long-term field validation of biological and integrated management strategies.