A study related to different formulations of vegetative cell of Pseudomonas fluorescence (Pseu-4) and Bacillus polymyxa (B.pol-15) together with challenge inoculation of pyricularia oryzae in the enhancement of IRS in Rice. Pyricularia oryzae disease patho systems was studied under pot culture with ADT-36. “It was observed that the application of (Pseu-4), (B.pol-15) as co-aggregates altered the biochemical and physiological parameters viz., reducing sugar and non-reducing sugars, Phenol content and defence mechanism by means of producing enzymes such as perocidase, polyphenol oxidase, (PPO) of rice plant to a significant level followed by co-inoculation and vegetative cell applications of PGPR”. When compare to that the co-aggregates of PGPR was found to augment all enzymes for the defence enzymes of rice plant, where as reduction and non-reducing sugar level also recorded, there by leads to reduction in Pyricularia oryzae incidence in rice grown of Tanjore regions of Tamil Nadu. EPS biosynthesis of PGPR cells during co-aggregation process might act as the defense mechanism of ISR, pathosystem, where as vegetative forms and co-inoculation processes does not produced of EPS and also responded poorly for the ISR pathosystem.