Native Bacillus amyloliquefaciens W2 as a potential biocontrol for Fusarium oxysporum R1 causing corm rot of Crocus sativus

Fusarium corm rot is the major destructive disease of Crocus sativus, a perennial herb whose stigma forms the commercially important spice “saffron”. In the present study we isolated a native Bacillus strain with antagonistic activity against a Fusarium oxysporum isolate causing the disease. Three fungi, Fusarium oxysporum, F. solani and Penicillium sp., were isolated from the corms showing classical symptoms of rot collected from saffron fields in the valley of Kashmir, India. The fungi were characterized using conidial morphology and molecular phylogeny. Among 400 bacterial isolates selected randomly from the rhizosphere and bulk soil of saffron fields, Bacillus amyloliquefaciens strain W2 was found effective against corm rot caused by F. oxysporum R1. Antagonistic activity of B. amyloliquefaciens W2 was confirmed in vitro using well diffusion and dual culture assay as well as in vivo by pot trials. The disease incidence in pot assays was 93 and 40 % in absence and presence of B. amyloliquefaciens W2 respectively. B. amyloliquefaciens W2 can be used as a potent biofungicide for corm rot diseases in C. sativus.