Indian Journal of Nematology

The enzymatic activities of selected strains of Pseudomonas fluorescens were assayed in tomato roots infested with the root knot nematode, Meloidogyne incognita under field conditions in Coimbatore, Tamil Nadu, India. Application of strains of P. fluorescens as liquid formulation through drip irrigation @ 500 ml/ha increased the level of peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) in tomato roots thereby reduced the root knot nematode infestation in the roots indicating the systemic resistance induced by the bacterial formulations. Consortial formulation of biocontrol agents viz., P. fluorescens, Pf 128 and Bacillus subtilis, Bbv 57 recorded the highest enzymatic activity and lowest nematode population in tomato roots compared to other strains either alone or in consortium. The results showed that plant growth promoting rhizobacterium (PGPR) P. fluorescens is capable of inducing systemic resistance against Meloidogyne incognita in tomato by the accumulation of the defense enzymes like PO, PPO and PAL.