Evaluation of nematicidal potential of Moringa oleifera extracts and novel rhizobacteria against Meloidogyne incognita in tomato

Wajahat Azeem ^1* Tariq Mukhtar ^1* Muhammad Inam Ul Haq ¹ Dr Muhammad Azam Khan ² Muhammad Suhail Ibrahim ² Ahmad Hassan ³ Homan Regmi ⁴ Larry Wayne Duncan ⁴

• ¹ Department of Plant Pathology, Faculty of Crop and Food Sciences, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan
• ² Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Punjab, Pakistan
• ³ Institute of Biochemistry & Biotechnology, University of the Punjab, Lahore, Punjab, Pakistan
• ⁴ Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States

The present study evaluated the effects of Moringa oleifera aqueous extracts and rhizobacterial strains, Bacillus australimaris (BA-LWD73) and B. thuringiensis (BT-WAG41), applied singly and in combination, on tomato growth and Meloidogyne incognita infection. Growth parameters, including plant height, root length, shoot and root biomass (fresh and dry), were significantly improved in most treatments compared to the control. The combined treatment of BA-LWD73 + M. oleifera showed the highest plant height (96.94 cm) and root length (30.48 cm), while BT-WAG41 + M. oleifera recorded the lowest values. 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 infection parameters, root gall rating, number of eggs per root system, second stage juveniles (J2) per 60 cm³ soil, and reproduction factor, were significantly reduced, particularly 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. aurtralimaris 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 synergistic potential of rhizobacteria and plant extracts in promoting tomato growth and suppressing M. incognita infection.