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Antimicrobial metabolites produced by antagonistic rhizobacteria are considered an important factor in reducing most root diseases. Hydrogen cyanide, protease,siderophore and some antibiotic compounds produced by fluorescent pseudomonads have been identified and structurally characterized among which 2,4-diacetylphloroglucinol is the most important antibiotic. Isolates Pf27, Pf26, Pf16, Pf15 and CHA0 strain had the most in hibitory effect on Pythium ultimum in vitro. Pf6 isolate had no effect on this species. Strains Pf8, Pf15, Pf16, Pf26, Pf27 and CHA0 demonstrated the greatest inhibition on Rhizoctonia solani. A total of 11 isolates including Pf2, Pf9, Pf15, Pf16, Pf22, Pf26, Pf27, Pf28, Pf31, Pf32 and CHA0 produced hydrogen cyanide. Fourteen isolates including Pf1, Pf2, Pf6, Pf12, Pf15, Pf21, Pf27, Pf 32 and CHA0 produced protease. Most of the bacteria produced siderophore. Bacterial isolates that generated the gratest amounts of siderophore included Pf1, Pf16, Pf26, Pf27, Pf32 and CHA0. None of the bacterial isolates were able to produce cellulase, being evident from the fact that there was no change of color on filter paper in a tube containing cellulose. Neither Bacillus subtilis isolates nor those belonging to P. fluorescens, Pf11, Pf17, Pf20 and Pf23, produced any siderophore. Among 19 strains of bacteria tested, only 15 produced detectable levels of 2, 4-diacetylphloroglucinol. Strain CHA0 produced 11.4 mg/ml of the antibiotic, the highest level among P. fluorescent studied. Strains Pf29 and Pf31 produced very low amounts of antibiotic and strains Pf3 and Pf21 produced none at all. The effects of growth condition were studied on four strains producing low, intermediate, and high levels of 2, 4-diacetylphloroglucinol.