Investigating the Effect of Pseudomonas Fluorescens on Fusarium oxysporum f.sp. Gladioli Causing Corm Rot Disease of Gladiolus

A detailed study was conducted to find out the efficacy of Pseudomonas fluorescens on fusarial corm
rot pathogen Fusarium oxysporum f. sp. gladioli in Department of Plant Protection, Allahabad
Agricultural Institute Deemed-University, Allahabad. The most destructive disease of gladiolus
throughout the world is Fusarium wilt caused by Fusarium oxysporum f. sp. gladioli; Gladiolus suffers
annually serious losses due to wilt and storage rot caused by F. oxysporum f. sp. gladioli. The strains
of P. fluorescens isolates from gladiolus rhizosphere had significantly inhibited the growth of F.
oxysporum f. sp. gladioli. Among the strains, PsL-4 of P. fluorescens has higher inhibitory action in
comparison with other strains. The strains of P. fluorescens also produced hydrogen cyanide (HCN)
which limited the growth of pathogen. The study also indicated the involvement of Siderophoremediated
antagonism in P. fluorescens. The metabolite production by the strain PsL-4 of P.
fluorescens had shown the antifungal activity against F. oxysporum f. sp. gladioli. The antibiotics
namely phenazine, phocyanine, pyreolnitrin and phoroglucinol were produced by some strains of P.
fluorescens against various diseases.