Plant-parasitic nematodes are severe soil-borne pathogens that cause significant damage to agricultural products each year, resulting in substantial financial losses globally. Thus, there is an urgent need to identify novel biological control agents or nematicides. The nematicidal potential of Bacillus subtilis-derived lipopeptides against Meloidogyne incognita was investigated at various concentrations (35 ppm, 25 ppm, 15 ppm, 5 ppm) under in vitro conditions. Egg hatching inhibition and mortality of second-stage juveniles (J2s) of M. incognita were analyzed after exposure for 6, 12, 24, 48, and 96 hours. Data showed that with the increase in concentration and exposure period, egg hatching inhibition and percent mortality increases. Maximum percent mortality of J2s was reported at 35ppm i.e., 45%, 55%, 67.75%, 77% and 85% at 6, 12, 24, 48 and 96 hrs, respectively. The maximum ovicidal activity was reported at 35ppm concentration, with 84.61% of eggs hatching inhibition on 96 hrs of the exposure period. The bacterial culture suspension of Bacillus subtilis and Pseudomonas putida at1.2x108cfu/ml, and the crude lipopeptide (35ppm) was also investigated as a biological control agent against M. incognita on tomato in a pot experiment under glasshouse condition. Combinational treatment of P. putida and B. subtilis culture, prior to inoculation of M. incognita on tomato plant caused a significant increase in plant growth attributes and in biochemical parameters over the inoculated control. In the same treatment, the maximum reduction in nematode population and root galling was recorded. However, in the crude lipopeptide experiment study, root dip and inoculation of crude lipopeptide in tomato after the introduction of M. incognita caused a major augment in all the parameters over the inoculated control. MALDI-TOF MS analysis of crude lipopeptide shows surfactin like molecules at m/z 1058 [M+Na]+. It is concluded that crude lipopeptide or combinational treatment of B. subtilis and P. putida culture suspension can be employed as a biocontrol agent against M. incognita and may act as a source of a novel nematicidal agent of bacterial origin.
