Effect of bioinoculants on rhizome rot disease of turmeric (Curcuma longa L.)

Abstract

Pythium sp. induced rhizome rot is a serious constraint throughout all turmeric-growing regions. Application of fungicides for rhizome rot has decreased the soil microbial biodiversity, which has resulted in the emergence of pathogen strains that are resistant to management. Under glasshouse conditions, the potential of bioagents isolated from the rhizosphere soil to control rhizome rot in turmeric was assessed. The lowest incidence of rhizome rot disease (14.60%) resulted by applying bioformulation P. chlororaphis PA23 and B. subtilis CBE4 as rhizome dip and soil on 3rd and 5th month. Turmeric height, girth and number of leaves per clump were all significantly improved by applying the consortial bioformulation. When B. subtilis CBE4 and P. chlororaphis PA23 were applied as consortial formulation against P. aphanidermatum, defense-related gene products including chitinase, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, b-1,3 glucanase, phenols, and proteins were induced which led to suppression of the incidence of rhizome rot disease.