Here we report the effects of aqueous extracts of the plant Moringa oleifera and rhizobacterial strains, Bacillus australimaris (BA-LWD73) and B. thuringiensis (BT-WAG41), applied singly and in combination, on tomato growth and Meloidogyne incognita infection. Plant height, root length, shoot and root biomass (fresh and dry), were significantly increased by most treatments compared to the control. The combined treatment of BA-LWD73 + M. oleifera produced the highest plant height (96.94 cm) and root length (30.48 cm). The highest shoot biomass was observed in BA-LWD73 alone treatment while root biomass was generally lower in all treatments than in the control. M. incognita induced, root gall rating, number of eggs per root system, second stage juveniles (J2), and reproduction rate, were significantly reduced in treatments involving M. oleifera and BA-LWD73, either alone or in combination. The lowest root gall rating (2.67) and J2 count (680) were observed in B. australimaris LWD73 + M. oleifera treatment. FTIR analysis of M. oleifera extract indicated the presence of functional groups such as hydroxyl, C=C, S=O, and C–O, suggesting bioactive potential. GC-MS analysis revealed six phytocompounds, with 5-Hydroxymethylfurfural (71.76%) as the dominant component, all known for antimicrobial and nematicidal activities. Moreover, volatile organic compounds from BA-LWD73 included 1H-Indole (87.46%) and 2-Nonanone (6.54%), known for their nematicidal properties. These findings highlight the potential of rhizobacteria and plant extracts in promoting tomato growth and suppressing M. incognita infection.

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.