Evaluation of bacterial formulations as potential biocontrol agents against the southern root-knot nematode, Meloidogyne incognita

Abstract

BackgroundBacterial bioagents, Pseudomonas fluorescens, P. putida, Bacillus amyloliquifaciens, and B. megaterium, have management potential against root-knot nematode (RKN), Meloidogyne incognita, in bottle gourd.ResultsField and laboratory experiments were conducted to evaluate the effect of bacterial bioagents Bacillus megaterium 1% WP (2 × 106 CFU/g), B. amyloliquifaciens 1% WP (2 × 108 CFU/g), Pseudomonas putida 1% WP (2 × 108 CFU/g), P. fluorescens 1% WP (2 × 109 CFU/g) on egg hatching and juvenile mortality of root-knot nematode, M. incognita. All the bacterial species inhibited the egg hatching in M. incognita and caused juvenile mortality. The lowest mean egg hatching in 120 h. after treatment was observed in P. putida (20.9% mean egg hatching), followed by P. fluorescens (21.1%), B. amyloliquifaciens (23.7%), and B. megaterium (24.7%) at 4% concentration of the formulated product against (47%) egg hatching in control. The juvenile mortality was found highest (57.1% mean mortality) in P. fluorescens in 120 h. of exposure, followed by P. putida (56.13%), B. megaterium (54.46%), and B. amyloliquifaciens (53.13%) at 4% concentration against 0.46 mean juvenile mortality in control, where distilled water was used. Under field conditions, the bottle gourd seeds that were treated either with B. amyloliquefaciens, B. megaterium, P. fluorescens, or P. putida at 10 g/kg seed along with the application of neem cake (1t/ha) significantly resulted in reduced root gall index and the number of nematode juveniles in soil and roots than the non-treated control.ConclusionThis study revealed that the tested bacterial bioagents, namely B. amyloquefaciens, B. megaterium, P. fluorescens, and P. putida, showed the potential for controlling of root knot nematode (RKN) in the laboratory as well as in field conditions in bottle gourd.