Bio-efficacy of Pseudomonas fluorescens isolates against foliar and soil borne pathogens

Abstract

This study assessed the antagonistic activity of five Pseudomonas fluorescens isolates (PF1-PF5) against key foliar and soil-borne pathogens, including Fusarium oxysporum f. sp. ciceri, Colletotrichum capsici, Alternaria alternata, and Rhizoctonia bataticola, using the dual culture method. The isolates showed significant variation in their ability to suppress pathogen growth. Among them, PF4 was most effective against F. oxysporum f. sp. ciceri, followed by PF5 and PF3, achieving inhibition rates of 70.96% and 70.67%, respectively. For R. bataticola, PF4 again showed the highest inhibition (72.50%), followed by PF5 (70.00%). Against C. capsici, PF4 recorded the greatest suppression (72.50%), with PF5 close behind at 69.48%. In the case of A. alternata, PF5 was the most effective, inhibiting up to 73.38% of pathogen growth. Overall, all P. fluorescens isolates significantly outperformed the control, with isolates PF1 through PF5 demonstrating strong and consistent biocontrol activity. These outcomes align with previous research supporting the role of P. fluorescens in biological disease management, attributed to mechanisms like antifungal compound production, competitive exclusion, and rhizosphere colonization. The findings underscore the potential of isolates PF4 and PF5 as promising biocontrol agents for managing diseases such as anthracnose, leaf blight, wilt, and dry root rot in