Evaluation of Rhizosphere Bacterial Antagonists for the Management of Fusarium Wilt in Tomato Plants

Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici is a serious problem limiting tomato production worldwide. The intent of the study was to evaluate potential of bacterial antagonists to suppress fusarium wilt disease development and evaluate the role of the strains as plant growth-promoting rhizobacteria (PGPR) in tomato. Among fifty-two bacterial strains isolated from rhizoplane and rhizosphere of healthy tomato roots, five isolates viz. isolate-01, isolate-17, isolate-23, isolate-24 and isolate-32 were found highly inhibitory against mycelial growth of Fusarium sp., in dual cultures. Highest inhibition of radial mycelial growth of pathogen in dual culture was induced by isolate-24 (72.2%) followed by isolate-32 (71.9%). In greenhouse experiments percent disease incidence (PDI) was lower in artificially inoculated tomato plants treated with isolate-32 (7.8%) and isolate-24 (8.9%), with percent disease reduction over control of 85.6% and 83.6%, respectively. These isolates also exhibited significant difference in seed germination percentage under artificial inoculation along with pathogen, highest germination percentage was recorded by isolate-32 (91%) followed by isolate-24 (89%) as compared to pathogen inoculated control (24%). The study concluded that the two native rhizobacteria isolated from root zone of healthy tomato plants could successfully protect the tomato plants from the lethal infection by Fusarium sp. while enhancing the germination of the treated plants.