Antifungal activity of different strains of Pseudomonas fluorescens were tested against some plant pathogens such as Alternaria cajanL Curvularia lunata, Fusarium sp.. Bipolaris sp. and Helminthosporium sp. in invitro. Different concentrations (1000,2000, 3000,4000 and 5000 pg/ml) of Pseudomonas fluorescens were used and maximum spore germination of fungus was inhibited at 4000 and 5000 pg/ml. The result indicated that all the strains of Pseudomonas fluorescens presented a most significant value against Alternaria cajani and Curvularia lunata. Out of the five strains studied, the best result was shown by Strain 1, which showed almost complete inhibition against pathogenic fungi such as Curvularia lunata and Fusarium sp. at 4000 and 5000 pg/ml while Strain - 5 was resistant against Fusarium sp. and Helminthosporium sp. at 5000 pg/ml. Among the fungus tested, bacterial strains Strain - 2 and Strain - 5 were found to be more sensitive to Fusarium sp. and Helminthosporium sp.

Keywords: Plant pathogen, Antifungal activity, Strain, Bio pesticides