Vol. 9, Special Issue 1, Part G (2025)

Turmeric (Curcuma longa) is a crucial spice crop in India, recognized for its culinary, medicinal, and cosmetic benefits. However, challenges such as pest infestations, particularly from root-knot nematodes, soil erosion, and fluctuating market prices hinder the yield and profitability of turmeric farming. To investigate the impact of root-knot nematodes, replicated pathogenicity and yield loss trials were conducted for two consecutive years (2020-2022) at the College of Agriculture, Chiplima, focusing on the turmeric variety Rajendra Sonia. Pathogenicity tests involved inoculating earthen pots with varying densities of Meloidogyne incognita (0, 10, 100, 1000, and 10,000 J2/kg soil). Results showed a progressive decline in relative water content, leaf water potential, and proline content of leaves as the inoculum density increased, while relative water deficit increased. Statistical analysis indicated significant differences among treatments, with pooled analysis showing highly significant effects. Histopathological examinations of infected roots revealed disorganization of xylem vessels and other cellular changes due to nematode invasion, impacting water uptake and reducing plant health. Yield loss trials in infested fields included treatments with carbofuran (2.0 kg a.i/ha) compared to untreated plots. Carbofuran-treated plots exhibited significant increases in plant height, leaf dimensions, shoot and root dry weight, and rhizome yield, alongside reductions in root-knot index and nematode populations by 45.76% in soil and 35.51% in roots. The avoidable loss in rhizome yield was estimated at 23.66% in the first year and 20.00% in the second, with reductions in yield attributing characters such as plant height, number of leaves, length, and breadth of leaf, number of tillers, shoot, and root dry weight irrespective of the year of investigation.