Implementing sustainable practices to combat root knot nematode infestation in tomato farming from Meghalaya

Root-knot nematodes (Meloidogyne spp.) are significant pests that cause considerable damage to crops, prompting a need for sustainable control methods. This study evaluated the nematicidal potential of fungal culture filtrates and botanicals as eco-friendly alternatives. In vitro tests demonstrated that Lemongrass oil (LG) (0.2%) achieved the highest mortality of nematode juveniles (J₂s) at 99.44% within 48 h, while Pochonia chlamydosporia (Pc) (2%) and Purpuricillium lilacinum (Pl) (2%) reduced egg hatching rates to 9.57% and 11.43%, respectively. Neem oil (NM) (0.2%) was the most effective in preventing J₂ root penetration (4.42%). In vivo, a combination treatment (T₇) of NM (0.2%), Trichoderma harzianum (Tz) (2%), Pl (2%), and LG (0.2%) applied at 10 day intervals significantly reduced the nematode reproduction factor to 0.035, comparable to the chemical control Bayer Velum Prime^® (Fluopyram 34.48% W/W SC) (0.031). T₅ (NM and Tz) resulted in the highest shoot biomass (236.73 ± 1.38 g), while Bayer Velum Prime^® (Fluopyram 34.48% W/W SC) increased root biomass (31.75 ± 1.24 g). Additionally, T₇ produced the longest shoots (63.37 ± 0.74 cm) and roots (36.80 ± 0.3 cm), with fewer root galls (55.67 ± 1.53) and egg masses (4 ± 0.01). T₇ also minimized the final soil nematode population to 106.33 ± 1.01 per 100 g, closely followed by T₈ (94.67 ± 0.89). These results indicate that combining NM, Tz, Pl and LG provide effective nematode control without phytotoxic effects, enhancing plant growth and offering a promising sustainable alternative to chemical nematicides.