Tomato (Lycopersicon esculentum. Mill) is an important and most popular vegetable crop worldwide. Among the various insect pests responsible for lowering the yield of tomato, the fruitworm, Helicoverpa armigera (Hubner) is a highly destructive pest causing serious damage. The present study was undertaken to analyse the role of certain microbial inoculants in enhancing insect resistance and in the selected tomato accession with the objective, to study the biochemical and biophysical factors of resistance against the fruit worm, H. armigera as influenced by microbial inoculants. Among the various microbial inoculants treatments, Pseudomonas + K-solubilizer (T9) nourished plants had higher biochemical and biophsical factors of resistance against H. armigera .