Influence of storage conditions on the shelf-life of microbial inoculants and their biocontrol activity towards damping-off pathogens

Abstract

Select microbial inoculants (Ral-3, 64-3, 63-28, and G8-32) were produced in proprietary liquid formulation, placed into commercial packages and stored at different temperature regimes. Shelflife of bacteria and level of antagonism were evaluated against the damping-off pathogens Pythium paracondrium, Rhizoctonia solani, Fusarium solani, and Cylindrocarpon destructans when retreived from the commercial packages after storage. Although differing in their antibiosis mechanisms, strains Ral-3 and 63-28 were significantly consistent in their antagonistic activity towards the fungi tested, irrespective of their storage conditions. Strains 64-3 and G8-32 did differ in their activity against the fungi. The storage temperature of 40°C affected the shelf-life of 64-3 by reducing it to Log 4.3 cfu/ml and the antagonistic activity of G8-32 was low against R. solani at all temperatures. However, the storage temperature of -20°C did not affect the activity or shelf-life of the strains.