Concentration-dependent nematicidal activity of Millettia pachyloba extract against the root-knot nematode Meloidogyne incognita in banana (Musa spp.)

Abstract

Root-knot nematodes (Meloidogyne spp.) are among the most destructive plant-parasitic nematodes affecting banana (Musa spp.), causing substantial yield losses worldwide. This study evaluated the concentration-dependent nematicidal activity of Millettia pachyloba ethanolic extract (MP-EA) against Meloidogyne incognita. LC-MS/MS profiling indicated that MP-EA was rich in flavonoids, terpenoids, and polyphenols. The extract was evaluated at concentrations ranging from 50 to 500 ppm using in vitro bioassays and greenhouse experiments to assess egg-hatching inhibition, juvenile mortality, enzymatic biomarkers, nematode infestation, and photosynthetic pigment content. Under in vitro conditions, MP-EA inhibited egg hatching by up to 52% relative to the negative control and induced more than 70% juvenile mortality after 72 h. In greenhouse experiments, the highest concentration reduced the root-knot index and soil nematode populations by more than 60% compared with the nematode-inoculated untreated control, while increasing catalase activity and carotenoid content by up to 28% and 24%, respectively. These findings indicate that MP-EA can suppress M. incognita and is associated with recovery of host physiological traits under greenhouse conditions. Collectively, the results highlight the potential of MP-EA as a botanical nematicide for sustainable management of root-knot nematodes in banana. However, further studies on formulation optimization, non-target safety, and field validation are required before practical application can be considered.