Sustainable Management Strategies for Plant Parasitic Nematodes in Subtropical Agriculture

Abstract: Across the subtropical belt, plant parasitic nematodes persist as one of the most economically destructive, yet chronically underestimated, threats to crop production. This chapter synthesizes current knowledge on nematode biology, host-parasite molecular interactions and the full spectrum of management options from conventional chemistry through biological agents, genetic resistance and precision sensing with particular focus on subtropical agricultural systems and the often-overlooked nematode problems of India and Northeast India. The core argument is that integrated nematode management (INM), combining complementary tactics targeting different life stages and operating through distinct mechanisms, consistently outperforms any single-strategy approach. Field data drawn from participatory trials in Karnataka, India, quantified root gall index reductions of 65-78% and marketable yield gains of 35-42% in tomato and chilli under an INM package combining the Mi-1-gene cultivars, Purpureocillium lilacinum bioformulations and neem cake amendments. Brazilian soybean trials integrating resistant cultivars, non-host rotation and Bacillus firmus reduced Heterodera glycines cyst populations by 85-92% over three seasons, generating a net economic return 35% above conventional nematicide programmes. Across East Africa and Southeast Asia, analogous INM frameworks delivered banana and rice yield increases of 40-60% and 18-32%, respectively. CRISPR-based susceptibility-gene editing, host-delivered RNA interference and metagenomics-guided microbiome engineering are reshaping what is achievable within a decade. The chapter also introduces a focused regional analysis of nematode pressure on tea, ginger, turmeric, black pepper and rice across Northeast India's eight states. The chapter focuses on climate-resilient resistance, AI-assisted population forecasting and rhizosphere consortia engineering as the most tractable priorities for sustainable subtropical nematode management. Keywords: Plant Parasitic Nematodes, INM, Biological Control, Northeast India, Molecular Resistance