Nematicidal Activity of Moringa oleifera Water Extracts and a Novel Rhizobacterium for the Suppression of Meloidogyne incognita in Tomato

Root-knot nematodes (Meloidogyne spp.) are major pests of vegetable crops, causing significant yield losses in numerous species worldwide. Their widespread distribution and polyphagous nature make them particularly challenging to manage effectively. The use of biological agents and botanical extracts has emerged as a sustainable alternative to chemical nematicides. The present study evaluated the effectiveness of aqueous extracts from Moringa oleifera and a novel strain of plant growth-promoting rhizobacteria, Bacillus australimaris strain LWD73, native to Florida, in reducing Meloidogyne incognita infection and enhancing plant growth. The combined application of M. oleifera extracts and B. australimaris LWD73 significantly reduced the number of galls, eggs per root system, second-stage juveniles (J2) per 60 cc of soil, and the nematode reproduction factor. Moreover, it improved key growth parameters in tomato cultivar HM1824. Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS) analyses of M. oleifera extracts identified antimicrobial and nematicidal phytochemicals. Similarly, solid-phase microextraction GC-MS (SPME-GC/MS) analysis of B. australimaris LWD73 revealed the presence of volatile organic compounds (VOCs), including 2-nonanone and 2-undecanone, which are known for their potent nematicidal properties. The synergistic application of M. oleifera and B. australimaris LWD73 demonstrated enhanced nematode suppression and improved plant growth, offering a promising, eco-friendly approach to managing root-knot nematodes in vegetable crops.